/*-------------------------------------------------------------------------
This source file is a part of OGRE
(Object-oriented Graphics Rendering Engine)

For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2014 Torus Knot Software Ltd
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE

You may alternatively use this source under the terms of a specific version of
the OGRE Unrestricted License provided you have obtained such a license from
Torus Knot Software Ltd.
-------------------------------------------------------------------------*/
#ifndef __SceneManager_H__
#define __SceneManager_H__

// Precompiler options
#include "OgrePrerequisites.h"

#include "OgrePlane.h"
#include "OgreQuaternion.h"
#include "OgreColourValue.h"
#include "OgreCommon.h"
#include "OgreSceneQuery.h"
#include "OgreAutoParamDataSource.h"
#include "OgreAnimationState.h"
#include "OgreRenderQueue.h"
#include "OgreRenderQueueSortingGrouping.h"
#include "OgreResourceGroupManager.h"
#include "OgreInstanceManager.h"
#include "OgreManualObject.h"
#include "OgreRenderSystem.h"
#include "OgreLodListener.h"
#include "OgreHeaderPrefix.h"
#include "OgreNameGenerator.h"

namespace Ogre {
    /** \addtogroup Core
    *  @{
    */
    /** \addtogroup Scene
    *  @{
    */

    typedef std::vector<TexturePtr> ShadowTextureList;

    /** Structure containing the configuration for one shadow texture. */
    struct ShadowTextureConfig
    {
        unsigned int width;
        unsigned int height;
        PixelFormat format;
        unsigned int fsaa;
        uint16      depthBufferPoolId;

        ShadowTextureConfig() : width(512), height(512), format(PF_BYTE_RGBA), fsaa(0), depthBufferPoolId(1) {}
    };

    typedef std::vector<ShadowTextureConfig> ShadowTextureConfigList;
    typedef ConstVectorIterator<ShadowTextureConfigList> ConstShadowTextureConfigIterator;

    _OgreExport bool operator== ( const ShadowTextureConfig& lhs, const ShadowTextureConfig& rhs );
    _OgreExport bool operator!= ( const ShadowTextureConfig& lhs, const ShadowTextureConfig& rhs );

    /** Structure for holding a position & orientation pair. */
    struct ViewPoint
    {
        Vector3 position;
        Quaternion orientation;
    };

    // Forward declarations
    class CompositorChain;
    class InstancedGeometry;
    class Rectangle2D;
    class LodListener;
    struct MovableObjectLodChangedEvent;
    struct EntityMeshLodChangedEvent;
    struct EntityMaterialLodChangedEvent;

    /** Structure collecting together information about the visible objects
    that have been discovered in a scene.
    */
    struct _OgreExport VisibleObjectsBoundsInfo
    {
        /// The axis-aligned bounds of the visible objects
        AxisAlignedBox aabb;
        /// The axis-aligned bounds of the visible shadow receiver objects
        AxisAlignedBox receiverAabb;
        /// The closest a visible object is to the camera
        Real minDistance;
        /// The farthest a visible objects is from the camera
        Real maxDistance;
        /// The closest a object in the frustum regardless of visibility / shadow caster flags
        Real minDistanceInFrustum;
        /// The farthest object in the frustum regardless of visibility / shadow caster flags
        Real maxDistanceInFrustum;

        VisibleObjectsBoundsInfo();
        void reset();
        void merge(const AxisAlignedBox& boxBounds, const Sphere& sphereBounds, 
            const Camera* cam, bool receiver=true);
        /** Merge an object that is not being rendered because it's not a shadow caster, 
            but is a shadow receiver so should be included in the range.
        */
        void mergeNonRenderedButInFrustum(const AxisAlignedBox& boxBounds, 
            const Sphere& sphereBounds, const Camera* cam);


    };

    struct ShadowTextureListener
    {
        ShadowTextureListener() {}
        virtual ~ShadowTextureListener() {}
        /** Event raised after all shadow textures have been rendered into for
            all queues / targets but before any other geometry has been rendered
            (including main scene geometry and any additional shadow receiver
            passes).
        @remarks
            This callback is useful for those that wish to perform some
            additional processing on shadow textures before they are used to
            render shadows. For example you could perform some filtering by
            rendering the existing shadow textures into another alternative
            shadow texture with a shader.
        @note
            This event will only be fired when texture shadows are in use.
        @param numberOfShadowTextures The number of shadow textures in use
        */
        virtual void shadowTexturesUpdated(size_t numberOfShadowTextures)
                    { (void)numberOfShadowTextures; }

        /** This event occurs just before the view & projection matrices are
            set for rendering into a shadow texture.
        @remarks
            You can use this event hook to perform some custom processing,
            such as altering the camera being used for rendering the light's
            view, including setting custom view & projection matrices if you
            want to perform an advanced shadow technique.
        @note
            This event will only be fired when texture shadows are in use.
        @param light Pointer to the light for which shadows are being rendered
        @param camera Pointer to the camera being used to render
        @param iteration For lights that use multiple shadow textures, the iteration number
        */
        virtual void shadowTextureCasterPreViewProj(Light* light,
            Camera* camera, size_t iteration)
                    { (void)light; (void)camera; (void)iteration; }

        /** This event occurs just before the view & projection matrices are
            set for re-rendering a shadow receiver.
        @remarks
            You can use this event hook to perform some custom processing,
            such as altering the projection frustum being used for rendering
            the shadow onto the receiver to perform an advanced shadow
            technique.
        @note
            This event will only be fired when texture shadows are in use.
        @param light Pointer to the light for which shadows are being rendered
        @param frustum Pointer to the projection frustum being used to project
            the shadow texture
        */
        virtual void shadowTextureReceiverPreViewProj(Light* light,
            Frustum* frustum)
                    { (void)light; (void)frustum; }

        /** Hook to allow the listener to override the ordering of lights for
            the entire frustum.

            Whilst ordinarily lights are sorted per rendered object
            (@ref MovableObject::queryLights), texture shadows adds another issue
            in that, given there is a finite number of shadow textures, we must
            choose which lights to render texture shadows from based on the entire
            frustum. These lights should always be listed first in every objects
            own list, followed by any other lights which will not cast texture
            shadows (either because they have shadow casting off, or there aren't
            enough shadow textures to service them).

            This hook allows you to override the detailed ordering of the lights
            per frustum. The default ordering is shadow casters first (which you
            must also respect if you override this method), and ordered
            by distance from the camera within those 2 groups. Obviously the closest
            lights with shadow casting enabled will be listed first. Only lights
            within the range of the frustum will be in the list.
        @param lightList The list of lights within range of the frustum which you
            may sort.
        @return true if you sorted the list, false otherwise.
        */
        virtual bool sortLightsAffectingFrustum(LightList& lightList)
                    { (void)lightList; return false; }
    };

    /** Manages the organisation and rendering of a 'scene': a collection of objects and potentially world geometry.

        This class defines the interface and the basic behaviour of a 
        'Scene Manager'. A SceneManager organises the culling and rendering of
        the scene, in conjunction with the RenderQueue. This class is designed 
        to be extended through subclassing in order to provide more specialised
        scene organisation structures for particular needs. The default 
        SceneManager culls based on a hierarchy of node bounding boxes, other
        implementations can use an octree (see OctreeSceneManager), a BSP
        tree (see BspSceneManager), and many other options. New SceneManager
        implementations can be added at runtime by plugins, see 
        SceneManagerEnumerator for the interfaces for adding new SceneManager
        types.

        There is a distinction between 'objects' (which subclass MovableObject, 
        and are movable, discrete objects in the world), and 'world geometry',
        which is large, generally static geometry. World geometry tends to 
        influence the SceneManager organisational structure (e.g. lots of indoor
        static geometry might result in a spatial tree structure) and as such
        world geometry is generally tied to a given SceneManager implementation,
        whilst MovableObject instances can be used with any SceneManager.
        Subclasses are free to define world geometry however they please.

        Multiple SceneManager instances can exist at one time, each one with 
        a distinct scene. Which SceneManager is used to render a scene is
        dependent on the Camera, which will always call back the SceneManager
        which created it to render the scene. 
     */
    class _OgreExport SceneManager : public SceneMgtAlloc
    {
    public:
        enum QueryTypeMask : uint32
        {
            /// Query type mask which will be used for world geometry @see SceneQuery
            WORLD_GEOMETRY_TYPE_MASK = 0x80000000,
            /// Query type mask which will be used for entities @see SceneQuery
            ENTITY_TYPE_MASK = 0x40000000,
            /// Query type mask which will be used for effects like billboardsets / particle systems @see SceneQuery
            FX_TYPE_MASK = 0x20000000,
            /// Query type mask which will be used for StaticGeometry  @see SceneQuery
            STATICGEOMETRY_TYPE_MASK = 0x10000000,
            /// Query type mask which will be used for lights  @see SceneQuery
            LIGHT_TYPE_MASK = 0x08000000,
            /// Query type mask which will be used for frusta and cameras @see SceneQuery
            FRUSTUM_TYPE_MASK = 0x04000000,
            /// User type mask limit
            USER_TYPE_MASK_LIMIT = FRUSTUM_TYPE_MASK
        };
        /** Comparator for material map, for sorting materials into render order (e.g. transparent last).
        */
        struct materialLess
        {
            _OgreExport bool operator()(const Material* x, const Material* y) const;
        };
        /// Comparator for sorting lights relative to a point
        struct lightLess
        {
            _OgreExport bool operator()(const Light* a, const Light* b) const;
        };

        /// Describes the stage of rendering when performing complex illumination
        enum IlluminationRenderStage
        {
            /// No special illumination stage
            IRS_NONE,
            /// Render to texture stage, used for texture based shadows
            IRS_RENDER_TO_TEXTURE,
            /// Render from shadow texture to receivers stage
            IRS_RENDER_RECEIVER_PASS
        };

        /** Enumeration of the possible modes allowed for processing the special case
        render queue list.
        @see SceneManager::setSpecialCaseRenderQueueMode
        */
        enum SpecialCaseRenderQueueMode
        {
            /// Render only the queues in the special case list
            SCRQM_INCLUDE,
            /// Render all except the queues in the special case list
            SCRQM_EXCLUDE
        };

        struct SkyDomeGenParameters
        {
            Real skyDomeCurvature;
            Real skyDomeTiling;
            Real skyDomeDistance;
            int skyDomeXSegments; 
            int skyDomeYSegments;
            int skyDomeYSegments_keep;
        };

        struct SkyPlaneGenParameters
        {
            Real skyPlaneScale;
            Real skyPlaneTiling; 
            Real skyPlaneBow; 
            int skyPlaneXSegments; 
            int skyPlaneYSegments; 
        };

        struct SkyBoxGenParameters
        {
            Real skyBoxDistance;
        };

        /** Class that allows listening in on the various stages of SceneManager
            processing, so that custom behaviour can be implemented from outside.
        */
        class Listener
        {
        public:
            Listener() {}
            virtual ~Listener() {}

            /** Called prior to updating the scene graph in this SceneManager.
            @remarks
                This is called before updating the scene graph for a camera.
            @param source The SceneManager instance raising this event.
            @param camera The camera being updated.
            */
            virtual void preUpdateSceneGraph(SceneManager* source, Camera* camera)
                        { (void)source; (void)camera; }

            /** Called after updating the scene graph in this SceneManager.
            @remarks
                This is called after updating the scene graph for a camera.
            @param source The SceneManager instance raising this event.
            @param camera The camera being updated.
            */
            virtual void postUpdateSceneGraph(SceneManager* source, Camera* camera)
                        { (void)source; (void)camera; }

            /** Called prior to searching for visible objects in this SceneManager.
            @remarks
                Note that the render queue at this stage will be full of the last
                render's contents and will be cleared after this method is called.
            @param source The SceneManager instance raising this event.
            @param irs The stage of illumination being dealt with. IRS_NONE for 
                a regular render, IRS_RENDER_TO_TEXTURE for a shadow caster render.
            @param v The viewport being updated. You can get the camera from here.
            */
            virtual void preFindVisibleObjects(SceneManager* source, 
                IlluminationRenderStage irs, Viewport* v)
                        { (void)source; (void)irs; (void)v; }

            /** Called after searching for visible objects in this SceneManager.
            @remarks
                Note that the render queue at this stage will be full of the current
                scenes contents, ready for rendering. You may manually add renderables
                to this queue if you wish.
            @param source The SceneManager instance raising this event.
            @param irs The stage of illumination being dealt with. IRS_NONE for 
                a regular render, IRS_RENDER_TO_TEXTURE for a shadow caster render.
            @param v The viewport being updated. You can get the camera from here.
            */
            virtual void postFindVisibleObjects(SceneManager* source, 
                IlluminationRenderStage irs, Viewport* v)
                        { (void)source; (void)irs; (void)v; }

            /** Event notifying the listener of the SceneManager's destruction. */
            virtual void sceneManagerDestroyed(SceneManager* source)
                        { (void)source; }
        };

        /** Inner helper class to implement the visitor pattern for rendering objects
            in a queue. 
        */
        class _OgreExport SceneMgrQueuedRenderableVisitor : public QueuedRenderableVisitor
        {
        private:
            /// Pass that was actually used at the grouping level
            const Pass* mUsedPass;
        public:
            SceneMgrQueuedRenderableVisitor() 
                :transparentShadowCastersMode(false) {}
            ~SceneMgrQueuedRenderableVisitor() {}
            void visit(const Pass* p, RenderableList& rs);
            void visit(RenderablePass* rp);

            /// Target SM to send renderables to
            SceneManager* targetSceneMgr;
            /// Are we in transparent shadow caster mode?
            bool transparentShadowCastersMode;
            /// Automatic light handling?
            bool autoLights;
            /// Manual light list
            const LightList* manualLightList;
            /// Scissoring if requested?
            bool scissoring;

        };
        /// Allow visitor helper to access protected methods
        friend class SceneMgrQueuedRenderableVisitor;

        typedef std::map<String, Camera* > CameraList;
        typedef std::map<String, Animation*> AnimationList;
        typedef std::map<String, MovableObject*> MovableObjectMap;
    protected:

        /// Subclasses can override this to ensure their specialised SceneNode is used.
        virtual SceneNode* createSceneNodeImpl(void);
        /// Subclasses can override this to ensure their specialised SceneNode is used.
        virtual SceneNode* createSceneNodeImpl(const String& name);

        /// Instance name
        String mName;

        /// Queue of objects for rendering
        std::unique_ptr<RenderQueue> mRenderQueue;

        /// The rendering system to send the scene to
        RenderSystem *mDestRenderSystem;

        /** Central list of cameras - for easy memory management and lookup.
        */
        CameraList mCameras;

        typedef std::map<String, StaticGeometry* > StaticGeometryList;
        StaticGeometryList mStaticGeometryList;
        typedef std::map<String, InstancedGeometry* > InstancedGeometryList;
        InstancedGeometryList mInstancedGeometryList;

        typedef std::map<String, InstanceManager*> InstanceManagerMap;
        InstanceManagerMap  mInstanceManagerMap;

        typedef std::vector<SceneNode*> SceneNodeList;

        /** Central list of SceneNodes - for easy memory management.
            @note
                Note that this list is used only for memory management; the structure of the scene
                is held using the hierarchy of SceneNodes starting with the root node. However you
                can look up nodes this way.
        */
        SceneNodeList mSceneNodes;

        /// additional map to speed up lookup by name
        std::map<String, SceneNode*> mNamedNodes;

        /// Camera in progress
        Camera* mCameraInProgress;
        /// Current Viewport
        Viewport* mCurrentViewport;

        /// Root scene node
        std::unique_ptr<SceneNode> mSceneRoot;

        /// Autotracking scene nodes
        typedef std::set<SceneNode*> AutoTrackingSceneNodes;
        AutoTrackingSceneNodes mAutoTrackingSceneNodes;

        // Sky params
        class _OgreExport SkyRenderer : public Listener, public Node::Listener
        {
        protected:
            SceneManager* mSceneManager;
            virtual void _updateRenderQueue(RenderQueue* queue) = 0;
            void nodeDestroyed(const Node*);
        public:
            enum BoxPlane
            {
                BP_FRONT = 0,
                BP_BACK = 1,
                BP_LEFT = 2,
                BP_RIGHT = 3,
                BP_UP = 4,
                BP_DOWN = 5
            };

            SkyRenderer(SceneManager* owner);

            SceneNode* mSceneNode;
            bool mEnabled;

            void setEnabled(bool enable);
            void postFindVisibleObjects(SceneManager* source, IlluminationRenderStage irs, Viewport* vp);
        };

        class _OgreExport SkyPlaneRenderer : public SkyRenderer
        {
            Entity* mSkyPlaneEntity;
            Plane mSkyPlane;
            void _updateRenderQueue(RenderQueue* queue);
        public:
            SkyPlaneRenderer(SceneManager* owner) : SkyRenderer(owner), mSkyPlaneEntity(0) {}
            SkyPlaneGenParameters mSkyPlaneGenParameters;
            void setSkyPlane(bool enable, const Plane& plane, const String& materialName,
                             Real scale, Real tiling, uint8 renderQueue, Real bow, int xsegments,
                             int ysegments, const String& groupName);
        } mSkyPlane;

        class _OgreExport SkyBoxRenderer : public SkyRenderer
        {
            std::unique_ptr<ManualObject> mSkyBoxObj;

            Quaternion mSkyBoxOrientation;
            void _updateRenderQueue(RenderQueue* queue);
        public:
            SkyBoxRenderer(SceneManager* owner) : SkyRenderer(owner) {}
            SkyBoxGenParameters mSkyBoxGenParameters;
            void setSkyBox(bool enable, const String& materialName, Real distance,
                           uint8 renderQueue, const Quaternion& orientation,
                           const String& groupName);
        } mSkyBox;

        class _OgreExport SkyDomeRenderer : public SkyRenderer
        {
            std::array<Entity*, 5> mSkyDomeEntity;
            Quaternion mSkyDomeOrientation;

            MeshPtr createSkydomePlane(
                BoxPlane bp,
                Real curvature, Real tiling, Real distance,
                const Quaternion& orientation,
                int xsegments, int ysegments, int ySegmentsToKeep,
                const String& groupName);
            void _updateRenderQueue(RenderQueue* queue);
        public:
            SkyDomeRenderer(SceneManager* owner)  : SkyRenderer(owner) {}
            SkyDomeGenParameters mSkyDomeGenParameters;
            void setSkyDome(bool enable, const String& materialName, Real curvature, Real tiling,
                            Real distance, uint8 renderQueue, const Quaternion& orientation,
                            int xsegments, int ysegments, int ysegments_keep,
                            const String& groupName);
        } mSkyDome;

        // Fog
        FogMode mFogMode;
        ColourValue mFogColour;
        Real mFogStart;
        Real mFogEnd;
        Real mFogDensity;

        typedef std::set<uint8> SpecialCaseRenderQueueList;
        SpecialCaseRenderQueueList mSpecialCaseQueueList;
        SpecialCaseRenderQueueMode mSpecialCaseQueueMode;
        uint8 mWorldGeometryRenderQueue;
        
        unsigned long mLastFrameNumber;
        bool mResetIdentityView;
        bool mResetIdentityProj;

        bool mNormaliseNormalsOnScale;
        bool mFlipCullingOnNegativeScale;
        CullingMode mPassCullingMode;

    protected:

        /** Visible objects bounding box list.
            @remarks
                Holds an ABB for each camera that contains the physical extends of the visible
                scene elements by each camera. The map is crucial for shadow algorithms which
                have a focus step to limit the shadow sample distribution to only valid visible
                scene elements.
        */
        typedef std::map< const Camera*, VisibleObjectsBoundsInfo> CamVisibleObjectsMap;
        CamVisibleObjectsMap mCamVisibleObjectsMap; 

        /// Cached light information, used to tracking light's changes
        struct _OgreExport LightInfo
        {
            Light* light;       /// Just a pointer for comparison, the light might destroyed for some reason
            int type;           /// Use int instead of Light::LightTypes to avoid header file dependence
            Real range;         /// Sets to zero if directional light
            Vector3 position;   /// Sets to zero if directional light
            uint32 lightMask;   /// Light mask

            bool operator== (const LightInfo& rhs) const
            {
                return light == rhs.light && type == rhs.type &&
                    range == rhs.range && position == rhs.position && lightMask == rhs.lightMask;
            }

            bool operator!= (const LightInfo& rhs) const
            {
                return !(*this == rhs);
            }
        };

        typedef std::vector<LightInfo> LightInfoList;

        LightList mLightsAffectingFrustum;
        LightInfoList mCachedLightInfos;
        LightInfoList mTestLightInfos; // potentially new list
        ulong mLightsDirtyCounter;

        /// Simple structure to hold MovableObject map and a mutex to go with it.
        struct MovableObjectCollection
        {
                    MovableObjectMap map;
                    OGRE_MUTEX(mutex);
        };
        typedef std::map<String, MovableObjectCollection*> MovableObjectCollectionMap;
        MovableObjectCollectionMap mMovableObjectCollectionMap;
        NameGenerator mMovableNameGenerator;
        /** Gets the movable object collection for the given type name.
        @remarks
            This method create new collection if the collection does not exist.
        */
        MovableObjectCollection* getMovableObjectCollection(const String& typeName);
        /** Gets the movable object collection for the given type name.
        @remarks
            This method throw exception if the collection does not exist.
        */
        const MovableObjectCollection* getMovableObjectCollection(const String& typeName) const;
        /// Mutex over the collection of MovableObject types
        OGRE_MUTEX(mMovableObjectCollectionMapMutex);

        /** Internal method for initialising the render queue.
        @remarks
            Subclasses can use this to install their own RenderQueue implementation.
        */
        virtual void initRenderQueue(void);

        struct _OgreExport ShadowRenderer
        {
            typedef std::vector<Camera*> CameraList;
            typedef std::map< const Camera*, const Light* > ShadowCamLightMapping;

            ShadowRenderer(SceneManager* owner);
            ~ShadowRenderer();

            SceneManager* mSceneManager;
            RenderSystem* mDestRenderSystem;

            ShadowTechnique mShadowTechnique;
            ColourValue mShadowColour;

            /// A pass designed to let us render shadow colour on white for texture shadows
            Pass* mShadowCasterPlainBlackPass;
            /// A pass designed to let us render shadow receivers for texture shadows
            Pass* mShadowReceiverPass;

            Pass* mShadowModulativePass;

            Pass* mShadowDebugPass;
            Pass* mShadowStencilPass;
            HardwareIndexBufferSharedPtr mShadowIndexBuffer;
            size_t mShadowIndexBufferSize;
            size_t mShadowIndexBufferUsedSize;
            static GpuProgramParametersSharedPtr msInfiniteExtrusionParams;
            static GpuProgramParametersSharedPtr msFiniteExtrusionParams;

            Pass* mShadowTextureCustomCasterPass;
            Pass* mShadowTextureCustomReceiverPass;

            SamplerPtr mBorderSampler;

            TexturePtr mNullShadowTexture;
            CameraList mShadowTextureCameras;
            LightList mShadowTextureCurrentCasterLightList;
            // ShadowCamera to light mapping
            ShadowCamLightMapping mShadowCamLightMapping;
            // Array defining shadow texture index in light list.
            std::vector<size_t> mShadowTextureIndexLightList;

            std::unique_ptr<Rectangle2D> mFullScreenQuad;

            ShadowTextureList mShadowTextures;

            bool mShadowAdditiveLightClip;
            bool mDebugShadows;
            bool mShadowMaterialInitDone;
            bool mShadowUseInfiniteFarPlane;
            Real mShadowDirLightExtrudeDist;

            Real mDefaultShadowFarDist;
            Real mDefaultShadowFarDistSquared;
            Real mShadowTextureOffset; /// Proportion of texture offset in view direction e.g. 0.4
            Real mShadowTextureFadeStart; /// As a proportion e.g. 0.6
            Real mShadowTextureFadeEnd; /// As a proportion e.g. 0.9
            bool mShadowTextureSelfShadow;
            bool mShadowTextureConfigDirty;
            bool mShadowCasterRenderBackFaces;

            ShadowTextureConfigList mShadowTextureConfigList;

            /// Array defining shadow count per light type.
            size_t mShadowTextureCountPerType[3];

            /// default shadow camera setup
            ShadowCameraSetupPtr mDefaultShadowCameraSetup;

            void setShadowTechnique(ShadowTechnique technique);

            /// Internal method for creating shadow textures (texture-based shadows)
            void ensureShadowTexturesCreated();
            void prepareShadowTextures(Camera* cam, Viewport* vp, const LightList* lightList);
            /// Internal method for destroying shadow textures (texture-based shadows)
            void destroyShadowTextures(void);

            /** Internal method for turning a regular pass into a shadow caster pass.
            @remarks
                This is only used for texture shadows, basically we're trying to
                ensure that objects are rendered solid black.
                This method will usually return the standard solid black pass for
                all fixed function passes, but will merge in a vertex program
                and fudge the AutoParamDataSource to set black lighting for
                passes with vertex programs.
            */
            const Pass* deriveShadowCasterPass(const Pass* pass);
            /** Internal method for turning a regular pass into a shadow receiver pass.
            @remarks
            This is only used for texture shadows, basically we're trying to
            ensure that objects are rendered with a projective texture.
            This method will usually return a standard single-texture pass for
            all fixed function passes, but will merge in a vertex program
            for passes with vertex programs.
            */
            const Pass* deriveShadowReceiverPass(const Pass* pass);

            void initShadowVolumeMaterials();
            void setShadowTextureCasterMaterial(const MaterialPtr& mat);
            void setShadowTextureReceiverMaterial(const MaterialPtr& mat);
            void setShadowColour(const ColourValue& colour);
            void render(RenderQueueGroup* group, QueuedRenderableCollection::OrganisationMode om);

            /** Render a group with the added complexity of additive stencil shadows. */
            void renderAdditiveStencilShadowedQueueGroupObjects(RenderQueueGroup* group,
                QueuedRenderableCollection::OrganisationMode om);
            /** Render a group with the added complexity of modulative stencil shadows. */
            void renderModulativeStencilShadowedQueueGroupObjects(RenderQueueGroup* group,
                QueuedRenderableCollection::OrganisationMode om);
            /** Render a group rendering only shadow casters. */
            void renderTextureShadowCasterQueueGroupObjects(RenderQueueGroup* group,
                QueuedRenderableCollection::OrganisationMode om);
            /** Render a group rendering only shadow receivers. */
            void renderTextureShadowReceiverQueueGroupObjects(RenderQueueGroup* group,
                QueuedRenderableCollection::OrganisationMode om);
            /** Render a group with the added complexity of modulative texture shadows. */
            void renderModulativeTextureShadowedQueueGroupObjects(RenderQueueGroup* group,
                QueuedRenderableCollection::OrganisationMode om);

            /** Render a group with additive texture shadows. */
            void renderAdditiveTextureShadowedQueueGroupObjects(RenderQueueGroup* group,
                QueuedRenderableCollection::OrganisationMode om);

            /**  Returns the shadow caster AAB for a specific light-camera combination */
            const VisibleObjectsBoundsInfo& getShadowCasterBoundsInfo(const Light* light, size_t iteration) const;

            /** Internal method for rendering all the objects for a given light into the
                stencil buffer.
            @param light The light source
            @param cam The camera being viewed from
            @param calcScissor Whether the method should set up any scissor state, or
                false if that's already been done
            */
            void renderShadowVolumesToStencil(const Light* light, const Camera* cam,
                bool calcScissor);

            /** Internal utility method for setting stencil state for rendering shadow volumes.
            @param secondpass Is this the second pass?
            @param zfail Should we be using the zfail method?
            @param twosided Should we use a 2-sided stencil?
            */
            void setShadowVolumeStencilState(bool secondpass, bool zfail, bool twosided);
            /** Render a set of shadow renderables. */
            void renderShadowVolumeObjects(const ShadowCaster::ShadowRenderableList& shadowRenderables,
                Pass* pass, const LightList *manualLightList, unsigned long flags,
                bool secondpass, bool zfail, bool twosided);

            size_t getShadowTexIndex(size_t lightIndex);

            void setShadowIndexBufferSize(size_t size);

            const TexturePtr& getShadowTexture(size_t shadowIndex);

            void resolveShadowTexture(TextureUnitState* tu, size_t shadowIndex, size_t shadowTexUnitIndex) const;

            void setShadowTextureSettings(uint16 size, uint16 count, PixelFormat fmt, uint16 fsaa,
                                          uint16 depthBufferPoolId);
            void setShadowTextureSize(unsigned short size);
            void setShadowTextureCount(size_t count);
            void setShadowTexturePixelFormat(PixelFormat fmt);
            void setShadowTextureFSAA(unsigned short fsaa);
            void setShadowTextureConfig(size_t shadowIndex, const ShadowTextureConfig& config);
            void setShadowTextureConfig(size_t shadowIndex, uint16 width, uint16 height, PixelFormat format,
                                        uint16 fsaa, uint16 depthBufferPoolId);

            typedef std::vector<ShadowCaster*> ShadowCasterList;
            ShadowCasterList mShadowCasterList;
            std::unique_ptr<SphereSceneQuery> mShadowCasterSphereQuery;
            std::unique_ptr<AxisAlignedBoxSceneQuery> mShadowCasterAABBQuery;

            typedef std::vector<ShadowTextureListener*> ListenerList;
            ListenerList mListeners;

            /// Inner class to use as callback for shadow caster scene query
            class _OgreExport ShadowCasterSceneQueryListener : public SceneQueryListener, public SceneMgtAlloc
            {
            protected:
                SceneManager* mSceneMgr;
                ShadowCasterList* mCasterList;
                bool mIsLightInFrustum;
                const PlaneBoundedVolumeList* mLightClipVolumeList;
                const Camera* mCamera;
                const Light* mLight;
                Real mFarDistSquared;
            public:
                ShadowCasterSceneQueryListener(SceneManager* sm) : mSceneMgr(sm),
                    mCasterList(0), mIsLightInFrustum(false), mLightClipVolumeList(0),
                    mCamera(0), mFarDistSquared(0) {}
                // Prepare the listener for use with a set of parameters
                void prepare(bool lightInFrustum, const PlaneBoundedVolumeList* lightClipVolumes,
                             const Light* light, const Camera* cam, ShadowCasterList* casterList,
                             Real farDistSquared)
                {
                    mCasterList = casterList;
                    mIsLightInFrustum = lightInFrustum;
                    mLightClipVolumeList = lightClipVolumes;
                    mCamera = cam;
                    mLight = light;
                    mFarDistSquared = farDistSquared;
                }
                bool queryResult(MovableObject* object);
                bool queryResult(SceneQuery::WorldFragment* fragment);
            };

            std::unique_ptr<ShadowCasterSceneQueryListener> mShadowCasterQueryListener;

            /** Internal method for locating a list of shadow casters which
                could be affecting the frustum for a given light.
            */
            const ShadowCasterList& findShadowCastersForLight(const Light* light, const Camera* camera);
            /// Internal method for firing the texture shadows updated event
            void fireShadowTexturesUpdated(size_t numberOfShadowTextures);
            /// Internal method for firing the pre caster texture shadows event
            void fireShadowTexturesPreCaster(Light* light, Camera* camera, size_t iteration);
            /// Internal method for firing the pre receiver texture shadows event
            void fireShadowTexturesPreReceiver(Light* light, Frustum* f);
            void sortLightsAffectingFrustum(LightList& lightList);
        } mShadowRenderer;

        /** Internal method to validate whether a Pass should be allowed to render.
        @remarks
            Called just before a pass is about to be used for rendering a group to
            allow the SceneManager to omit it if required. A return value of false
            skips this pass. 
        */
        bool validatePassForRendering(const Pass* pass);

        /** Internal method to validate whether a Renderable should be allowed to render.
        @remarks
        Called just before a pass is about to be used for rendering a Renderable to
        allow the SceneManager to omit it if required. A return value of false
        skips it. 
        */
        bool validateRenderableForRendering(const Pass* pass, const Renderable* rend);

        /// Flag indicating whether SceneNodes will be rendered as a set of 3 axes
        bool mDisplayNodes;
        std::unique_ptr<DebugDrawer> mDebugDrawer;

        /// Storage of animations, lookup by name
        AnimationList mAnimationsList;
        OGRE_MUTEX(mAnimationsListMutex);
        AnimationStateSet mAnimationStates;
        
        /** Internal method used by _renderSingleObject to set the world transform */
        void setWorldTransform(Renderable* rend);

        /** Internal method used by _renderSingleObject to render a single light pass */
        void issueRenderWithLights(Renderable* rend, const Pass* pass,
                                   const LightList* pLightListToUse,
                                   bool lightScissoringClipping);

        /** Internal method used by _renderSingleObject to deal with renderables
            which override the camera's own view / projection matrices. */
        void resetViewProjMode();

        typedef std::vector<RenderQueueListener*> RenderQueueListenerList;
        RenderQueueListenerList mRenderQueueListeners;

        typedef std::vector<RenderObjectListener*> RenderObjectListenerList;
        RenderObjectListenerList mRenderObjectListeners;
        typedef std::vector<Listener*> ListenerList;
        ListenerList mListeners;
        /// Internal method for firing the queue start event
        void firePreRenderQueues();
        /// Internal method for firing the queue end event
        void firePostRenderQueues();
        /// Internal method for firing the queue start event, returns true if queue is to be skipped
        virtual bool fireRenderQueueStarted(uint8 id, const String& invocation);
        /// Internal method for firing the queue end event, returns true if queue is to be repeated
        virtual bool fireRenderQueueEnded(uint8 id, const String& invocation);
        /// Internal method for firing when rendering a single object.
        void fireRenderSingleObject(Renderable* rend, const Pass* pass, const AutoParamDataSource* source,
            const LightList* pLightList, bool suppressRenderStateChanges);
        /// Internal method for firing pre update scene graph event
        void firePreUpdateSceneGraph(Camera* camera);
        /// Internal method for firing post update scene graph event
        void firePostUpdateSceneGraph(Camera* camera);
        /// Internal method for firing find visible objects event
        void firePreFindVisibleObjects(Viewport* v);
        /// Internal method for firing find visible objects event
        void firePostFindVisibleObjects(Viewport* v);
        /// Internal method for firing destruction event
        void fireSceneManagerDestroyed();
        /** Internal method for setting the destination viewport for the next render. */
        void setViewport(Viewport *vp);

        /** Flag that indicates if all of the scene node's bounding boxes should be shown as a wireframe. */
        bool mShowBoundingBoxes;      

        /** Internal method for rendering all objects using the default queue sequence. */
        void renderVisibleObjectsDefaultSequence(void);
        /** Internal method for preparing the render queue for use with each render. */
        void prepareRenderQueue(void);


        /** Internal utility method for rendering a single object. 
        @remarks
            Assumes that the pass has already been set up.
        @copydetail _injectRenderWithPass
        @param lightScissoringClipping If true, passes that have the getLightScissorEnabled
        and/or getLightClipPlanesEnabled flags will cause calculation and setting of
        scissor rectangle and user clip planes.
        */
        void renderSingleObject(Renderable* rend, const Pass* pass,
            bool lightScissoringClipping, bool doLightIteration, const LightList* manualLightList = 0);

        /** Internal method for creating the AutoParamDataSource instance. */
        AutoParamDataSource* createAutoParamDataSource(void) const
        {
            return OGRE_NEW AutoParamDataSource();
        }

        /// Utility class for calculating automatic parameters for gpu programs
        std::unique_ptr<AutoParamDataSource> mAutoParamDataSource;

        GpuProgramParametersPtr mFixedFunctionParams;

        CompositorChain* mActiveCompositorChain;
        bool mLateMaterialResolving;

        IlluminationRenderStage mIlluminationStage;

        /// Struct for caching light clipping information for re-use in a frame
        struct LightClippingInfo
        {
            RealRect scissorRect;
            PlaneList clipPlanes;
            bool scissorValid;
            unsigned long clipPlanesValid;
            LightClippingInfo() : scissorValid(false), clipPlanesValid(false) {}

        };
        typedef std::map<Light*, LightClippingInfo> LightClippingInfoMap;
        LightClippingInfoMap mLightClippingInfoMap;
        unsigned long mLightClippingInfoMapFrameNumber;

        /** Default sorting routine which sorts lights which cast shadows
            to the front of a list, sub-sorting by distance.
        @remarks
            Since shadow textures are generated from lights based on the
            frustum rather than individual objects, a shadow and camera-wise sort is
            required to pick the best lights near the start of the list. Up to 
            the number of shadow textures will be generated from this.
        */
        struct lightsForShadowTextureLess
        {
            _OgreExport bool operator()(const Light* l1, const Light* l2) const;
        };


        /** Internal method for locating a list of lights which could be affecting the frustum.
        @remarks
            Custom scene managers are encouraged to override this method to make use of their
            scene partitioning scheme to more efficiently locate lights, and to eliminate lights
            which may be occluded by world geometry.
            If the list of lights is different to the list returned by
            SceneManager::_getLightsAffectingFrustum before this method was called, then this
            method should update that cached list and call SceneManager::_notifyLightsDirty to
            mark that the internal light cache has changed.
        */
        virtual void findLightsAffectingFrustum(const Camera* camera);
        /// Internal method for setting up materials for shadows
        virtual void initShadowVolumeMaterials(void);
        /// Internal method for creating shadow textures (texture-based shadows)
        virtual void ensureShadowTexturesCreated();
        /// Internal method for destroying shadow textures (texture-based shadows)
        virtual void destroyShadowTextures(void);

        typedef std::vector<InstanceManager*>      InstanceManagerVec;
        InstanceManagerVec mDirtyInstanceManagers;
        InstanceManagerVec mDirtyInstanceMgrsTmp;

        /** Updates all instance managaers with dirty instance batches. @see _addDirtyInstanceManager */
        void updateDirtyInstanceManagers(void);
        
        void _destroySceneNode(SceneNodeList::iterator it);
    public:
        //A render context, used to store internal data for pausing/resuming rendering
        struct RenderContext
        {
            RenderQueue* renderQueue;   
            Viewport* viewport;
            Camera* camera;
            CompositorChain* activeChain;
            RenderSystem::RenderSystemContext* rsContext;
        };

        /** Pause rendering of the frame. This has to be called when inside a renderScene call
            (Usually using a listener of some sort)
        */
        RenderContext* _pauseRendering();
        /** Resume rendering of the frame. This has to be called after a _pauseRendering call
        @param context The rendring context, as returned by the _pauseRendering call
        */
        void _resumeRendering(RenderContext* context);

    protected:
        /// Visibility mask used to show / hide objects
        uint32 mVisibilityMask;
        bool mFindVisibleObjects;

        /** Render a group in the ordinary way */
        void renderBasicQueueGroupObjects(RenderQueueGroup* pGroup,
            QueuedRenderableCollection::OrganisationMode om);
        /** Render a set of objects, see renderSingleObject for param definitions
            @remarks
            transparentShadowCastersMode is intended to be used to render the shadows of transparent objects which have
            transparency_casts_shadows set to 'on' in their material
        */
        void renderObjects(const QueuedRenderableCollection& objs,
            QueuedRenderableCollection::OrganisationMode om, bool lightScissoringClipping,
            bool doLightIteration, const LightList* manualLightList = 0, bool transparentShadowCastersMode = false);

        /** Update the state of the global render queue splitting based on a shadow
        option change. */
        void updateRenderQueueSplitOptions(void);
        /** Update the state of the render queue group splitting based on a shadow
        option change. */
        void updateRenderQueueGroupSplitOptions(RenderQueueGroup* group,
            bool suppressShadows, bool suppressRenderState);

        /// Set up a scissor rectangle from a group of lights
        ClipResult buildAndSetScissor(const LightList& ll, const Camera* cam);
        /// Update a scissor rectangle from a single light
        void buildScissor(const Light* l, const Camera* cam, RealRect& rect);
        void resetScissor();
        /// Build a set of user clip planes from a single non-directional light
        ClipResult buildAndSetLightClip(const LightList& ll);
        void buildLightClip(const Light* l, PlaneList& planes);
        void resetLightClip();
        void checkCachedLightClippingInfo(bool forceScissorRectsInvalidation = false);

        /// The active renderable visitor class - subclasses could override this
        SceneMgrQueuedRenderableVisitor* mActiveQueuedRenderableVisitor;
        /// Storage for default renderable visitor
        SceneMgrQueuedRenderableVisitor mDefaultQueuedRenderableVisitor;

        /// Whether to use camera-relative rendering
        bool mCameraRelativeRendering;
        Affine3 mCachedViewMatrix;

        /// Last light sets
        uint32 mLastLightHash;
        /// Gpu params that need rebinding (mask of GpuParamVariability)
        uint16 mGpuParamsDirty;

        void useLights(const LightList* lights, ushort limit);
        void bindGpuProgram(GpuProgram* prog);
        void updateGpuProgramParameters(const Pass* p);

        /// Set of registered LOD listeners
        typedef std::set<LodListener*> LodListenerSet;
        LodListenerSet mLodListeners;

        /// List of movable object LOD changed events
        typedef std::vector<MovableObjectLodChangedEvent> MovableObjectLodChangedEventList;
        MovableObjectLodChangedEventList mMovableObjectLodChangedEvents;

        /// List of entity mesh LOD changed events
        typedef std::vector<EntityMeshLodChangedEvent> EntityMeshLodChangedEventList;
        EntityMeshLodChangedEventList mEntityMeshLodChangedEvents;

        /// List of entity material LOD changed events
        typedef std::vector<EntityMaterialLodChangedEvent> EntityMaterialLodChangedEventList;
        EntityMaterialLodChangedEventList mEntityMaterialLodChangedEvents;

    public:
        /** Constructor.
        */
        SceneManager(const String& instanceName);

        /** Default destructor.
        */
        virtual ~SceneManager();


        /** Mutex to protect the scene graph from simultaneous access from
            multiple threads.
        @remarks
            If you are updating the scene in a separate thread from the rendering
            thread, then you should lock this mutex before making any changes to 
            the scene graph - that means creating, modifying or deleting a
            scene node, or attaching / detaching objects. It is <b>your</b> 
            responsibility to take out this lock, the detail methods on the nodes
            will not do it for you (for the reasons discussed below).
        @par
            Note that locking this mutex will prevent the scene being rendered until 
            it is unlocked again. Therefore you should do this sparingly. Try
            to create any objects you need separately and fully prepare them
            before doing all your scene graph work in one go, thus keeping this
            lock for the shortest time possible.
        @note
            A single global lock is used rather than a per-node lock since 
            it keeps the number of locks required during rendering down to a 
            minimum. Obtaining a lock, even if there is no contention, is not free
            so for performance it is good to do it as little as possible. 
            Since modifying the scene in a separate thread is a fairly
            rare occurrence (relative to rendering), it is better to keep the 
            locking required during rendering lower than to make update locks
            more granular.
        */
        OGRE_MUTEX(sceneGraphMutex);

        /** Return the instance name of this SceneManager. */
        const String& getName(void) const { return mName; }

        /** Retrieve the type name of this scene manager.
        @remarks
            This method has to be implemented by subclasses. It should
            return the type name of this SceneManager which agrees with 
            the type name of the SceneManagerFactory which created it.
        */
        virtual const String& getTypeName(void) const = 0;

        typedef MapIterator<CameraList> CameraIterator;
        /// @name Cameras
        /// @{
        /** Creates a camera to be managed by this scene manager.
            @remarks
                This camera must be added to the scene at a later time using
                the attachObject method of the SceneNode class.
            @param
                name Name to give the new camera.
        */
        virtual Camera* createCamera(const String& name);

        /** Retrieves a pointer to the named camera.
        @note Throws an exception if the named instance does not exist
        */
        Camera* getCamera(const String& name) const;

        /** Returns whether a camera with the given name exists.
        */
        bool hasCamera(const String& name) const;

        /** Removes a camera from the scene.
            @remarks
                This method removes a previously added camera from the scene.
                The camera is deleted so the caller must ensure no references
                to it's previous instance (e.g. in a SceneNode) are used.
            @param
                cam Pointer to the camera to remove
        */
        virtual void destroyCamera(Camera *cam);

        /** Removes a camera from the scene.
            @remarks
                This method removes an camera from the scene based on the
                camera's name rather than a pointer.
        */
        virtual void destroyCamera(const String& name);

        /** Removes (and destroys) all cameras from the scene.
            @remarks
                Some cameras are internal created to dealing with texture shadow,
                their aren't supposed to destroy outside. So, while you are using
                texture shadow, don't call this method, or you can set the shadow
                technique other than texture-based, which will destroy all internal
                created shadow cameras and textures.
        */
        virtual void destroyAllCameras(void);

        /** Set whether to use camera-relative co-ordinates when rendering, ie
            to always place the camera at the origin and move the world around it.
        @remarks
            This is a technique to alleviate some of the precision issues associated with
            rendering far from the origin, where single-precision floats as used in most
            GPUs begin to lose their precision. Instead of including the camera
            translation in the view matrix, it only includes the rotation, and
            the world matrices of objects must be expressed relative to this.
        @note
            If you need this option, you will probably also need to enable double-precision
            mode in Ogre (OGRE_DOUBLE_PRECISION), since even though this will
            alleviate the rendering precision, the source camera and object positions will still
            suffer from precision issues leading to jerky movement.
        */
        void setCameraRelativeRendering(bool rel) { mCameraRelativeRendering = rel; }

        /** Get whether to use camera-relative co-ordinates when rendering, ie
            to always place the camera at the origin and move the world around it.
        */
        bool getCameraRelativeRendering() const { return mCameraRelativeRendering; }

        /** Returns a specialised MapIterator over all cameras in the scene.
        @deprecated use getCameras()
        */
        OGRE_DEPRECATED CameraIterator getCameraIterator(void) {
            return CameraIterator(mCameras.begin(), mCameras.end());
        }
        /** Returns a const version of the camera list.
        */
        const CameraList& getCameras() const { return mCameras; }
        /// @}

        /// @name Lights
        /// @{
        /** Creates a light for use in the scene.
            @remarks
                Lights can either be in a fixed position and independent of the
                scene graph, or they can be attached to SceneNodes so they derive
                their position from the parent node. Either way, they are created
                using this method so that the SceneManager manages their
                existence.
            @param
                name The name of the new light, to identify it later.
        */
        virtual Light* createLight(const String& name);

        /// @overload
        Light* createLight(const String& name, Light::LightTypes type)
        {
            auto l = createLight(name);
            l->setType(type);
            return l;
        }

        /** Creates a light with a generated name. */
        virtual Light* createLight();

        /// @overload
        Light* createLight(Light::LightTypes type)
        {
            auto l = createLight();
            l->setType(type);
            return l;
        }

        /** Returns a pointer to the named Light which has previously been added to the scene.
        @note Throws an exception if the named instance does not exist
        */
        virtual Light* getLight(const String& name) const;

        /** Returns whether a light with the given name exists.
        */
        virtual bool hasLight(const String& name) const;

        /** Retrieve a set of clipping planes for a given light. 
        */
        const PlaneList& getLightClippingPlanes(Light* l);

        /** Retrieve a scissor rectangle for a given light and camera. 
        */
        const RealRect& getLightScissorRect(Light* l, const Camera* cam);

        /** Scissor rects are cached during frame, and this cache should be explicitly invalidated
            if several renders are done during one frame using different projections matrices,
            for example for tiled, stereo or multiview orthographic projection rendering.
        */
        virtual void invalidatePerFrameScissorRectCache();

        /** Removes the named light from the scene and destroys it.
            @remarks
                Any pointers held to this light after calling this method will be invalid.
        */
        virtual void destroyLight(const String& name);

        /** Removes the light from the scene and destroys it based on a pointer.
            @remarks
                Any pointers held to this light after calling this method will be invalid.
        */
        virtual void destroyLight(Light* light);
        /** Removes and destroys all lights in the scene.
        */
        virtual void destroyAllLights(void);

        /** Advanced method to increase the lights dirty counter due to lights having changed.
        @remarks
            The SceneManager tracks the list of lights affecting the current frustum, and if
            changes are detected (including changes to the light list itself or to a light's
            position or attenuation range) then it increases the lights dirty counter.
        @par
            You could call this method to force all the objects in the scene to re-populate
            their light list, but doing so may harm performance so should be avoided if possible.
        */
        void _notifyLightsDirty(void);

        /** Advanced method to gets the lights dirty counter.
        @remarks
            The SceneManager tracks the list of lights affecting the current frustum, and if
            changes are detected (including changes to the light list itself or to a light's
            position or attenuation range) then it increases the lights dirty counter.
        */
        ulong _getLightsDirtyCounter(void) const { return mLightsDirtyCounter; }

        /** Get the list of lights which could be affecting the frustum.
        @remarks
            This returns a cached light list which is populated when rendering the scene.
        */
        const LightList& _getLightsAffectingFrustum(void) const;

        /** Populate a light list with an ordered set of the lights which are closest
        to the position specified.
        @remarks
            Note that since directional lights have no position, they are always considered
            closer than any point lights and as such will always take precedence.
            The returned lights are those in the cached list of lights (i.e. those
            returned by SceneManager::_getLightsAffectingFrustum) sorted by distance.
        @par
            The number of items in the list may exceed the maximum number of lights supported
            by the renderer, but the extraneous ones will never be used. In fact the limit will
            be imposed by Pass::getMaxSimultaneousLights.
        @param position The position at which to evaluate the list of lights
        @param radius The bounding radius to test
        @param destList List to be populated with ordered set of lights; will be cleared by
            this method before population.
        @param lightMask The mask with which to include / exclude lights
        */
        void _populateLightList(const Vector3& position, Real radius, LightList& destList, uint32 lightMask = 0xFFFFFFFF);

        /// @overload
        void _populateLightList(const SceneNode* sn, Real radius, LightList& destList, uint32 lightMask = 0xFFFFFFFF);
        /// @}

        /// @name Scene Nodes
        /// @{
        /** Creates an instance of a SceneNode.
            @remarks
                Note that this does not add the SceneNode to the scene hierarchy.
                This method is for convenience, since it allows an instance to
                be created for which the SceneManager is responsible for
                allocating and releasing memory, which is convenient in complex
                scenes.
            @par
                To include the returned SceneNode in the scene, use the addChild
                method of the SceneNode which is to be it's parent.
            @par
                Note that this method takes no parameters, and the node created is unnamed (it is
                actually given a generated name, which you can retrieve if you want).
                If you wish to create a node with a specific name, call the alternative method
                which takes a name parameter.
        */
        virtual SceneNode* createSceneNode(void);

        /// @overload
        virtual SceneNode* createSceneNode(const String& name);

        /** Destroys a SceneNode.
        @remarks
            This allows you to physically delete an individual SceneNode if you want to.
            Note that this is not normally recommended, it's better to allow SceneManager
            to delete the nodes when the scene is cleared.
        */
        virtual void destroySceneNode(SceneNode* sn);

        /// @overload
        virtual void destroySceneNode(const String& name);

        /** Gets the SceneNode at the root of the scene hierarchy.
            @remarks
                The entire scene is held as a hierarchy of nodes, which
                allows things like relative transforms, general changes in
                rendering state etc (See the SceneNode class for more info).
                In this basic SceneManager class, the application using
                Ogre is free to structure this hierarchy however it likes,
                since it has no real significance apart from making transforms
                relative to each node (more specialised subclasses will
                provide utility methods for building specific node structures
                e.g. loading a BSP tree).
            @par
                However, in all cases there is only ever one root node of
                the hierarchy, and this method returns a pointer to it.
        */
        SceneNode* getRootSceneNode(void);

        /** Retrieves a named SceneNode from the scene graph.

            If you chose to name a SceneNode as you created it, you can look it
            up wherever it is in the scene graph using this method.
            @param name
            @param throwExceptionIfNotFound Throws an exception if the named instance does not exist
        */
        SceneNode* getSceneNode(const String& name, bool throwExceptionIfNotFound = true) const;

        /** Returns whether a scene node with the given name exists.
        */
        bool hasSceneNode(const String& name) const { return getSceneNode(name, false) != NULL; }

        /** Tells the SceneManager whether it should render the SceneNodes which
            make up the scene as well as the objects in the scene.
        @remarks
            This method is mainly for debugging purposes. If you set this to 'true',
            each node will be rendered as a set of 3 axes to allow you to easily see
            the orientation of the nodes.
        */
        void setDisplaySceneNodes(bool display);
        /** Returns true if all scene nodes axis are to be displayed */
        bool getDisplaySceneNodes(void) const {return mDisplayNodes;}

        /** Allows all bounding boxes of scene nodes to be displayed. */
        void showBoundingBoxes(bool bShow);

        /** Returns if all bounding boxes of scene nodes are to be displayed */
        bool getShowBoundingBoxes() const;

        DebugDrawer* getDebugDrawer() const { return mDebugDrawer.get(); }
        /// @}

        /** Prefab shapes available without loading a model.
            @note
                Minimal implementation at present.
            @todo
                Add more prefabs (teapots, teapots!!!)
        */
        enum PrefabType {
            PT_PLANE,
            PT_CUBE,
            PT_SPHERE
        };
        /// @name Entities
        /// @{
        /** Create an Entity (instance of a discrete mesh).
            @param
                entityName The name to be given to the entity (must be unique).
            @param
                meshName The name of the Mesh it is to be based on (e.g. 'knot.oof'). The
                mesh will be loaded if it is not already.
            @param groupName The resource name where the mesh lives
        */
        Entity* createEntity(const String& entityName, const String& meshName, const String& groupName = ResourceGroupManager::AUTODETECT_RESOURCE_GROUP_NAME );

        /** Create an Entity (instance of a discrete mesh).
            @param
                entityName The name to be given to the entity (must be unique).
            @param
                pMesh The pointer to the Mesh it is to be based on.
        */
        Entity* createEntity(const String& entityName, const MeshPtr& pMesh );

        /** Create an Entity (instance of a discrete mesh) with an autogenerated name.
            @param
                meshName The name of the Mesh it is to be based on (e.g. 'knot.oof'). The
                mesh will be loaded if it is not already.
        */
        Entity* createEntity(const String& meshName);

        /** Create an Entity (instance of a discrete mesh) with an autogenerated name.
            @param
                pMesh The pointer to the Mesh it is to be based on.
        */
        Entity* createEntity(const MeshPtr& pMesh);

        /** Create an Entity (instance of a discrete mesh) from a range of prefab shapes.
            @param
                entityName The name to be given to the entity (must be unique).
            @param
                ptype The prefab type.
        */
        Entity* createEntity(const String& entityName, PrefabType ptype);

        /** Create an Entity (instance of a discrete mesh) from a range of prefab shapes, generating the name.
            @param ptype The prefab type.
        */
        Entity* createEntity(PrefabType ptype);
        /** Retrieves a pointer to the named Entity. 
        @note Throws an exception if the named instance does not exist
        */
        Entity* getEntity(const String& name) const;
        /** Returns whether an entity with the given name exists.
        */
        bool hasEntity(const String& name) const;

        /** Removes & destroys an Entity from the SceneManager.
            @warning
                Must only be done if the Entity is not attached
                to a SceneNode. It may be safer to wait to clear the whole
                scene if you are unsure use clearScene.
            @see
                SceneManager::clearScene
        */
        void destroyEntity(Entity* ent);

        /// @overload
        void destroyEntity(const String& name);

        /** Removes & destroys all Entities.
            @warning
                Again, use caution since no Entity must be referred to
                elsewhere e.g. attached to a SceneNode otherwise a crash
                is likely. Use clearScene if you are unsure (it clears SceneNode
                entries too.)
            @see
                SceneManager::clearScene
        */
        virtual void destroyAllEntities(void);
        /// @}

        /// @name Manual Objects
        /// @{
        /** Create a ManualObject, an object which you populate with geometry
            manually through a GL immediate-mode style interface.
        @param
            name The name to be given to the object (must be unique).
        */
        ManualObject* createManualObject(const String& name);
        /** Create a ManualObject, an object which you populate with geometry
        manually through a GL immediate-mode style interface, generating the name.
        */
        ManualObject* createManualObject();
        /** Retrieves a pointer to the named ManualObject. 
        @note Throws an exception if the named instance does not exist
        */
        ManualObject* getManualObject(const String& name) const;
        /** Returns whether a manual object with the given name exists.
        */
        bool hasManualObject(const String& name) const;

        /** Removes & destroys a ManualObject from the SceneManager.
        */
        void destroyManualObject(ManualObject* obj);
        /// @overload
        void destroyManualObject(const String& name);
        /** Removes & destroys all ManualObjects from the SceneManager.
        */
        void destroyAllManualObjects(void);
        /// @}

        /// @name Billboard Chains
        /// @{
        /** Create a BillboardChain, an object which you can use to render
            a linked chain of billboards.
        @param
            name The name to be given to the object (must be unique).
        */
        BillboardChain* createBillboardChain(const String& name);
        /** Create a BillboardChain, an object which you can use to render
        a linked chain of billboards, with a generated name.
        */
        BillboardChain* createBillboardChain();
        /** Retrieves a pointer to the named BillboardChain. 
        @note Throws an exception if the named instance does not exist
        */
        BillboardChain* getBillboardChain(const String& name) const;
        /** Returns whether a billboard chain with the given name exists.
        */
        bool hasBillboardChain(const String& name) const;

        /** Removes & destroys a BillboardChain from the SceneManager.
        */
        void destroyBillboardChain(BillboardChain* obj);
        /// @overload
        void destroyBillboardChain(const String& name);
        /** Removes & destroys all BillboardChains from the SceneManager.
        */
        void destroyAllBillboardChains(void);
        /** Create a RibbonTrail, an object which you can use to render
            a linked chain of billboards which follows one or more nodes.
        @param
            name The name to be given to the object (must be unique).
        */
        RibbonTrail* createRibbonTrail(const String& name);
        /** Create a RibbonTrail, an object which you can use to render
        a linked chain of billboards which follows one or more nodes, generating the name.
        */
        RibbonTrail* createRibbonTrail();
        /** Retrieves a pointer to the named RibbonTrail. 
        @note Throws an exception if the named instance does not exist
        */
        RibbonTrail* getRibbonTrail(const String& name) const;
        /** Returns whether a ribbon trail with the given name exists.
        */
        bool hasRibbonTrail(const String& name) const;

        /** Removes & destroys a RibbonTrail from the SceneManager.
        */
        void destroyRibbonTrail(RibbonTrail* obj);
        /// @overload
        void destroyRibbonTrail(const String& name);
        /** Removes & destroys all RibbonTrails from the SceneManager.
        */
        void destroyAllRibbonTrails(void);
        /// @}

        /// @name Particle System
        /// @{
        /** Creates a particle system based on a template.
        @remarks
            This method creates a new ParticleSystem instance based on the named template
            (defined through ParticleSystemManager::createTemplate) and returns a 
            pointer to the caller. The caller should not delete this object, it will be freed at system shutdown, 
            or can be released earlier using the destroyParticleSystem method.
        @par
            Each system created from a template takes the template's settings at the time of creation, 
            but is completely separate from the template from there on. 
        @par
            Creating a particle system does not make it a part of the scene. As with other MovableObject
            subclasses, a ParticleSystem is not rendered until it is attached to a SceneNode. 
        @par
            This is probably the more useful particle system creation method since it does not require manual
            setup of the system. Note that the initial quota is based on the template but may be changed later.
        @param 
            name The name to give the new particle system instance.
        @param 
            templateName The name of the template to base the new instance on.
        */
        ParticleSystem* createParticleSystem(const String& name,
            const String& templateName);
        /** Create a blank particle system.
        @remarks
            This method creates a new, blank ParticleSystem instance and returns a pointer to it.
            The caller should not delete this object, it will be freed at system shutdown, or can
            be released earlier using the destroyParticleSystem method.
        @par
            The instance returned from this method won't actually do anything because on creation a
            particle system has no emitters. The caller should manipulate the instance through it's 
            ParticleSystem methods to actually create a real particle effect. 
        @par
            Creating a particle system does not make it a part of the scene. As with other MovableObject
            subclasses, a ParticleSystem is not rendered until it is attached to a SceneNode. 
        @param
            name The name to give the ParticleSystem.
        @param 
            quota The maximum number of particles to allow in this system. 
        @param
            resourceGroup The resource group which will be used to load dependent resources
        */
        ParticleSystem* createParticleSystem(const String& name,
            size_t quota = 500, 
            const String& resourceGroup = ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);

        /** Create a blank particle system with a generated name.
        @remarks
            This method creates a new, blank ParticleSystem instance and returns a pointer to it.
            The caller should not delete this object, it will be freed at system shutdown, or can
            be released earlier using the destroyParticleSystem method.
        @par
            The instance returned from this method won't actually do anything because on creation a
            particle system has no emitters. The caller should manipulate the instance through it's 
            ParticleSystem methods to actually create a real particle effect. 
        @par
            Creating a particle system does not make it a part of the scene. As with other MovableObject
            subclasses, a ParticleSystem is not rendered until it is attached to a SceneNode. 
        @param 
            quota The maximum number of particles to allow in this system. 
        @param
            resourceGroup The resource group which will be used to load dependent resources
        */
        ParticleSystem* createParticleSystem(size_t quota = 500,
            const String& resourceGroup = ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);
        /** Retrieves a pointer to the named ParticleSystem. 
        @note Throws an exception if the named instance does not exist
        */
        ParticleSystem* getParticleSystem(const String& name) const;
        /** Returns whether a particle system with the given name exists.
        */
        bool hasParticleSystem(const String& name) const;

        /** Removes & destroys a ParticleSystem from the SceneManager.
        */
        void destroyParticleSystem(ParticleSystem* obj);
        /** Removes & destroys a ParticleSystem from the SceneManager.
        */
        void destroyParticleSystem(const String& name);
        /** Removes & destroys all ParticleSystems from the SceneManager.
        */
        void destroyAllParticleSystems(void);
        /// @}

        /** Empties the entire scene, inluding all SceneNodes, Entities, Lights, 
            BillboardSets etc. Cameras are not deleted at this stage since
            they are still referenced by viewports, which are not destroyed during
            this process.
        */
        virtual void clearScene(void);

        /** Sets the ambient light level to be used for the scene.
            @remarks
                This sets the colour and intensity of the ambient light in the scene, i.e. the
                light which is 'sourceless' and illuminates all objects equally.
                The colour of an object is affected by a combination of the light in the scene,
                and the amount of light that object reflects (in this case based on the Material::ambient
                property).
            @remarks
                By default the ambient light in the scene is ColourValue::Black, i.e. no ambient light. This
                means that any objects rendered with a Material which has lighting enabled (see Material::setLightingEnabled)
                will not be visible unless you have some dynamic lights in your scene.
        */
        void setAmbientLight(const ColourValue& colour);

        /** Returns the ambient light level to be used for the scene.
        */
        const ColourValue& getAmbientLight(void) const;

        /// @name World Geometry
        /// @{
        /** Sets the source of the 'world' geometry, i.e. the large, mainly static geometry
            making up the world e.g. rooms, landscape etc.
            @remarks
                Depending on the type of SceneManager (subclasses will be specialised
                for particular world geometry types) you have requested via the Root or
                SceneManagerEnumerator classes, you can pass a filename to this method and it
                will attempt to load the world-level geometry for use. If you try to load
                an inappropriate type of world data an exception will be thrown. The default
                SceneManager cannot handle any sort of world geometry and so will always
                throw an exception. However subclasses like BspSceneManager can load
                particular types of world geometry e.g. "q3dm1.bsp".
        */
        virtual void setWorldGeometry(const String& filename);

        /** @overload
            @param stream Data stream containing data to load
            @param typeName String identifying the type of world geometry
                contained in the stream - not required if this manager only 
                supports one type of world geometry.
        */
        virtual void setWorldGeometry(DataStreamPtr& stream, 
            const String& typeName = BLANKSTRING);

        /** Estimate the number of loading stages required to load the named
            world geometry. 
        @remarks
            This method should be overridden by SceneManagers that provide
            custom world geometry that can take some time to load. They should
            return from this method a count of the number of stages of progress
            they can report on whilst loading. During real loading (setWorldGeometry),
            they should call ResourceGroupManager::_notifyCustomStage* exactly
            that number of times when loading the geometry for real.
        @note 
            The default is to return 0, ie to not report progress. 
        */
        virtual size_t estimateWorldGeometry(const String& filename)
        { (void)filename; return 0; }

        /** @overload
        @param stream Data stream containing data to load
        @param typeName String identifying the type of world geometry
            contained in the stream - not required if this manager only 
            supports one type of world geometry.
        */      
        virtual size_t estimateWorldGeometry(DataStreamPtr& stream, 
            const String& typeName = BLANKSTRING)
        { (void)stream; (void)typeName; return 0; }
        /// @}

        /** Asks the SceneManager to provide a suggested viewpoint from which the scene should be viewed.
            @remarks
                Typically this method returns the origin unless a) world geometry has been loaded using
                SceneManager::setWorldGeometry and b) that world geometry has suggested 'start' points.
                If there is more than one viewpoint which the scene manager can suggest, it will always suggest
                the first one unless the random parameter is true.
            @param
                random If true, and there is more than one possible suggestion, a random one will be used. If false
                the same one will always be suggested.
            @return
                On success, true is returned.
            @par
                On failure, false is returned.
        */
        virtual ViewPoint getSuggestedViewpoint(bool random = false);

        /** Method for setting a specific option of the Scene Manager. These options are usually
            specific for a certain implemntation of the Scene Manager class, and may (and probably
            will) not exist across different implementations.
            @param
                strKey The name of the option to set
            @param
                pValue A pointer to the value - the size should be calculated by the scene manager
                based on the key
            @return
                On success, true is returned.
            @par
                On failure, false is returned.
        */
        virtual bool setOption( const String& strKey, const void* pValue )
        { (void)strKey; (void)pValue; return false; }

        /** Method for getting the value of an implementation-specific Scene Manager option.
            @param
                strKey The name of the option
            @param
                pDestValue A pointer to a memory location where the value will
                be copied. Currently, the memory will be allocated by the
                scene manager, but this may change
            @return
                On success, true is returned and pDestValue points to the value of the given
                option.
            @par
                On failure, false is returned and pDestValue is set to NULL.
        */
        virtual bool getOption( const String& strKey, void* pDestValue )
        { (void)strKey; (void)pDestValue; return false; }

        /** Method for verifying whether the scene manager has an implementation-specific
            option.
            @param
                strKey The name of the option to check for.
            @return
                If the scene manager contains the given option, true is returned.
            @remarks
                If it does not, false is returned.
        */
        virtual bool hasOption( const String& strKey ) const
        { (void)strKey; return false; }

        /** Method for getting all possible values for a specific option. When this list is too large
            (i.e. the option expects, for example, a float), the return value will be true, but the
            list will contain just one element whose size will be set to 0.
            Otherwise, the list will be filled with all the possible values the option can
            accept.
            @param
                strKey The name of the option to get the values for.
            @param
                refValueList A reference to a list that will be filled with the available values.
            @return
                On success (the option exists), true is returned.
            @par
                On failure, false is returned.
        */
        virtual bool getOptionValues( const String& strKey, StringVector& refValueList )
        { (void)strKey; (void)refValueList; return false; }

        /** Method for getting all the implementation-specific options of the scene manager.
            @param
                refKeys A reference to a list that will be filled with all the available options.
            @return
                On success, true is returned. On failure, false is returned.
        */
        virtual bool getOptionKeys( StringVector& refKeys )
        { (void)refKeys; return false; }

        /** Internal method for updating the scene graph ie the tree of SceneNode instances managed by this class.
            @remarks
                This must be done before issuing objects to the rendering pipeline, since derived transformations from
                parent nodes are not updated until required. This SceneManager is a basic implementation which simply
                updates all nodes from the root. This ensures the scene is up to date but requires all the nodes
                to be updated even if they are not visible. Subclasses could trim this such that only potentially visible
                nodes are updated.
        */
        virtual void _updateSceneGraph(Camera* cam);

        /** Internal method which parses the scene to find visible objects to render.
            @remarks
                If you're implementing a custom scene manager, this is the most important method to
                override since it's here you can apply your custom world partitioning scheme. Once you
                have added the appropriate objects to the render queue, you can let the default
                SceneManager objects _renderVisibleObjects handle the actual rendering of the objects
                you pick.
            @par
                Any visible objects will be added to a rendering queue, which is indexed by material in order
                to ensure objects with the same material are rendered together to minimise render state changes.
        */
        virtual void _findVisibleObjects(Camera* cam, VisibleObjectsBoundsInfo* visibleBounds, bool onlyShadowCasters);

        /** Internal method for issuing the render operation.*/
        void _issueRenderOp(Renderable* rend, const Pass* pass);

        /** Sends visible objects found in _findVisibleObjects to the rendering engine.
        */
        void _renderVisibleObjects(void);

        /** Prompts the class to send its contents to the renderer.
            @remarks
                This method prompts the scene manager to send the
                contents of the scene it manages to the rendering
                pipeline, possibly preceded by some sorting, culling
                or other scene management tasks. Note that this method is not normally called
                directly by the user application; it is called automatically
                by the Ogre rendering loop.
            @param camera Pointer to a camera from whose viewpoint the scene is to
                be rendered.
            @param vp The target viewport
            @param includeOverlays unused
        */
        virtual void _renderScene(Camera* camera, Viewport* vp, bool includeOverlays = true);

        /** Notifies the scene manager of its destination render system
            @remarks
                Called automatically by RenderSystem::addSceneManager
                this method simply notifies the manager of the render
                system to which its output must be directed.
            @param
                sys Pointer to the RenderSystem subclass to be used as a render target.
        */
        void _setDestinationRenderSystem(RenderSystem* sys);

        /** Notifies the scene manager that hardware resources were lost
            @remarks
                Called automatically by RenderSystem if hardware resources
                were lost and can not be restored using some internal mechanism.
                Among affected resources are manual meshes without loaders, 
                manual textures without loaders, ManualObjects, etc.
        */
        void _releaseManualHardwareResources();

        /** Notifies the scene manager that hardware resources should be restored
            @remarks
                Called automatically by RenderSystem if hardware resources
                were lost and can not be restored using some internal mechanism.
                Among affected resources are manual meshes without loaders, 
                manual textures without loaders, ManualObjects, etc.
        */
        void _restoreManualHardwareResources();

        /// @name Sky Rendering
        /// @{
        /** Enables / disables a 'sky plane' i.e. a plane at constant
            distance from the camera representing the sky.
            @remarks
                You can create sky planes yourself using the standard mesh and
                entity methods, but this creates a plane which the camera can
                never get closer or further away from - it moves with the camera.
                (NB you could create this effect by creating a world plane which
                was attached to the same SceneNode as the Camera too, but this
                would only apply to a single camera whereas this plane applies to
                any camera using this scene manager).
            @note
                To apply scaling, scrolls etc to the sky texture(s) you
                should use the TextureUnitState class methods.
            @param
                enable True to enable the plane, false to disable it
            @param
                plane Details of the plane, i.e. it's normal and it's
                distance from the camera.
            @param
                materialName The name of the material the plane will use
            @param
                scale The scaling applied to the sky plane - higher values
                mean a bigger sky plane - you may want to tweak this
                depending on the size of plane.d and the other
                characteristics of your scene
            @param
                tiling How many times to tile the texture across the sky.
                Applies to all texture layers. If you need finer control use
                the TextureUnitState texture coordinate transformation methods.
            @param
                drawFirst If true, the plane is drawn before all other
                geometry in the scene, without updating the depth buffer.
                This is the safest rendering method since all other objects
                will always appear in front of the sky. However this is not
                the most efficient way if most of the sky is often occluded
                by other objects. If this is the case, you can set this
                parameter to false meaning it draws <em>after</em> all other
                geometry which can be an optimisation - however you must
                ensure that the plane.d value is large enough that no objects
                will 'poke through' the sky plane when it is rendered.
            @param
                bow If zero, the plane will be completely flat (like previous
                versions.  If above zero, the plane will be curved, allowing
                the sky to appear below camera level.  Curved sky planes are 
                simular to skydomes, but are more compatible with fog.
            @param xsegments, ysegments
                Determines the number of segments the plane will have to it. This
                is most important when you are bowing the plane, but may also be useful
                if you need tessellation on the plane to perform per-vertex effects.
            @param groupName
                The name of the resource group to which to assign the plane mesh.
        */

        void setSkyPlane(
            bool enable,
            const Plane& plane, const String& materialName, Real scale = 1000,
            Real tiling = 10, bool drawFirst = true, Real bow = 0, 
            int xsegments = 1, int ysegments = 1, 
            const String& groupName = ResourceGroupManager::AUTODETECT_RESOURCE_GROUP_NAME);
        /// @overload
        void _setSkyPlane(
            bool enable,
            const Plane& plane, const String& materialName, Real scale = 1000,
            Real tiling = 10, uint8 renderQueue = RENDER_QUEUE_SKIES_EARLY, Real bow = 0, 
            int xsegments = 1, int ysegments = 1, 
            const String& groupName = ResourceGroupManager::AUTODETECT_RESOURCE_GROUP_NAME);

        /** Enables / disables a 'sky plane' */
        void setSkyPlaneEnabled(bool enable) { mSkyPlane.setEnabled(enable); }

        /** Return whether a key plane is enabled */
        bool isSkyPlaneEnabled(void) const { return mSkyPlane.mEnabled; }

        /** Get the sky plane node, if enabled. */
        SceneNode* getSkyPlaneNode(void) const { return mSkyPlane.mSceneNode; }

        /** Get the parameters used to construct the SkyPlane, if any **/
        const SkyPlaneGenParameters& getSkyPlaneGenParameters(void) const { return mSkyPlane.mSkyPlaneGenParameters; }

        /** Enables / disables a 'sky box' i.e. a 6-sided box at constant
            distance from the camera representing the sky.
            @remarks
                You could create a sky box yourself using the standard mesh and
                entity methods, but this creates a plane which the camera can
                never get closer or further away from - it moves with the camera.
                (NB you could create this effect by creating a world box which
                was attached to the same SceneNode as the Camera too, but this
                would only apply to a single camera whereas this skybox applies
                to any camera using this scene manager).
            @par
                The material you use for the skybox can either contain layers
                which are single textures, or they can be cubic textures, i.e.
                made up of 6 images, one for each plane of the cube. See the
                TextureUnitState class for more information.
            @param
                enable True to enable the skybox, false to disable it
            @param
                materialName The name of the material the box will use
            @param
                distance Distance in world coorinates from the camera to
                each plane of the box. The default is normally OK.
            @param
                drawFirst If true, the box is drawn before all other
                geometry in the scene, without updating the depth buffer.
                This is the safest rendering method since all other objects
                will always appear in front of the sky. However this is not
                the most efficient way if most of the sky is often occluded
                by other objects. If this is the case, you can set this
                parameter to false meaning it draws <em>after</em> all other
                geometry which can be an optimisation - however you must
                ensure that the distance value is large enough that no
                objects will 'poke through' the sky box when it is rendered.
            @param
                orientation Optional parameter to specify the orientation
                of the box. By default the 'top' of the box is deemed to be
                in the +y direction, and the 'front' at the -z direction.
                You can use this parameter to rotate the sky if you want.
            @param groupName
                The name of the resource group to which to assign the plane mesh.
        */
        void setSkyBox(
            bool enable, const String& materialName, Real distance = 5000,
            bool drawFirst = true, const Quaternion& orientation = Quaternion::IDENTITY,
            const String& groupName = ResourceGroupManager::AUTODETECT_RESOURCE_GROUP_NAME);

        /// @overload
        void _setSkyBox(
            bool enable, const String& materialName, Real distance = 5000,
            uint8 renderQueue = RENDER_QUEUE_SKIES_EARLY, const Quaternion& orientation = Quaternion::IDENTITY,
            const String& groupName = ResourceGroupManager::AUTODETECT_RESOURCE_GROUP_NAME);

        /** Enables / disables a 'sky box' */
        void setSkyBoxEnabled(bool enable) { mSkyBox.setEnabled(enable); }

        /** Return whether a skybox is enabled */
        bool isSkyBoxEnabled(void) const { return mSkyBox.mEnabled; }

        /** Get the skybox node, if enabled. */
        SceneNode* getSkyBoxNode(void) const { return mSkyBox.mSceneNode; }

        /** Get the parameters used to generate the current SkyBox, if any */
        const SkyBoxGenParameters& getSkyBoxGenParameters(void) const { return mSkyBox.mSkyBoxGenParameters; }

        /** Enables / disables a 'sky dome' i.e. an illusion of a curved sky.
            @remarks
                A sky dome is actually formed by 5 sides of a cube, but with
                texture coordinates generated such that the surface appears
                curved like a dome. Sky domes are appropriate where you need a
                realistic looking sky where the scene is not going to be
                'fogged', and there is always a 'floor' of some sort to prevent
                the viewer looking below the horizon (the distortion effect below
                the horizon can be pretty horrible, and there is never anyhting
                directly below the viewer). If you need a complete wrap-around
                background, use the setSkyBox method instead. You can actually
                combine a sky box and a sky dome if you want, to give a positional
                backdrop with an overlayed curved cloud layer.
            @par
                Sky domes work well with 2D repeating textures like clouds. You
                can change the apparent 'curvature' of the sky depending on how
                your scene is viewed - lower curvatures are better for 'open'
                scenes like landscapes, whilst higher curvatures are better for
                say FPS levels where you don't see a lot of the sky at once and
                the exaggerated curve looks good.
            @param
                enable True to enable the skydome, false to disable it
            @param
                materialName The name of the material the dome will use
            @param
                curvature The curvature of the dome. Good values are
                between 2 and 65. Higher values are more curved leading to
                a smoother effect, lower values are less curved meaning
                more distortion at the horizons but a better distance effect.
            @param
                tiling How many times to tile the texture(s) across the
                dome.
            @param
                distance Distance in world coorinates from the camera to
                each plane of the box the dome is rendered on. The default
                is normally OK.
            @param
                drawFirst If true, the dome is drawn before all other
                geometry in the scene, without updating the depth buffer.
                This is the safest rendering method since all other objects
                will always appear in front of the sky. However this is not
                the most efficient way if most of the sky is often occluded
                by other objects. If this is the case, you can set this
                parameter to false meaning it draws <em>after</em> all other
                geometry which can be an optimisation - however you must
                ensure that the distance value is large enough that no
                objects will 'poke through' the sky when it is rendered.
            @param
                orientation Optional parameter to specify the orientation
                of the dome. By default the 'top' of the dome is deemed to
                be in the +y direction, and the 'front' at the -z direction.
                You can use this parameter to rotate the sky if you want.
            @param groupName
                The name of the resource group to which to assign the plane mesh.
            @param xsegments, ysegments, ysegments_keep see @ref MeshManager::createCurvedIllusionPlane
                */
        void setSkyDome(
            bool enable, const String& materialName, Real curvature = 10,
            Real tiling = 8, Real distance = 4000, bool drawFirst = true,
            const Quaternion& orientation = Quaternion::IDENTITY,
            int xsegments = 16, int ysegments = 16, int ysegments_keep = -1,
            const String& groupName = ResourceGroupManager::AUTODETECT_RESOURCE_GROUP_NAME);

        /// @overload
        void _setSkyDome(
            bool enable, const String& materialName, Real curvature = 10,
            Real tiling = 8, Real distance = 4000, uint8 renderQueue = RENDER_QUEUE_SKIES_EARLY,
            const Quaternion& orientation = Quaternion::IDENTITY,
            int xsegments = 16, int ysegments = 16, int ysegments_keep = -1,
            const String& groupName = ResourceGroupManager::AUTODETECT_RESOURCE_GROUP_NAME);

        /** Enables / disables a 'sky dome' */
        void setSkyDomeEnabled(bool enable) { mSkyDome.setEnabled(enable); }

        /** Return whether a skydome is enabled */
        bool isSkyDomeEnabled(void) const { return mSkyDome.mEnabled; }

        /** Get the sky dome node, if enabled. */
        SceneNode* getSkyDomeNode(void) const { return mSkyDome.mSceneNode; }

        /** Get the parameters used to generate the current SkyDome, if any */
        const SkyDomeGenParameters& getSkyDomeGenParameters(void) const { return mSkyDome.mSkyDomeGenParameters; }
        /// @}

        /// @name Fogging
        /// @{
        /** Sets the fogging mode applied to the scene.
            @remarks
                This method sets up the scene-wide fogging effect. These settings
                apply to all geometry rendered, UNLESS the material with which it
                is rendered has it's own fog settings (see Material::setFog).
            @param
                mode Set up the mode of fog as described in the FogMode
                enum, or set to FOG_NONE to turn off.
            @param
                colour The colour of the fog. Either set this to the same
                as your viewport background colour, or to blend in with a
                skydome or skybox.
            @param
                expDensity The density of the fog in FOG_EXP or FOG_EXP2
                mode, as a value between 0 and 1. The default is 0.001. 
            @param
                linearStart Distance in world units at which linear fog starts to
                encroach. Only applicable if mode is
                FOG_LINEAR.
            @param
                linearEnd Distance in world units at which linear fog becomes completely
                opaque. Only applicable if mode is
                FOG_LINEAR.
        */
        void setFog(
            FogMode mode = FOG_NONE, const ColourValue& colour = ColourValue::White,
            Real expDensity = 0.001f, Real linearStart = 0.0f, Real linearEnd = 1.0f);

        /** Returns the fog mode for the scene.
        */
        FogMode getFogMode(void) const;

        /** Returns the fog colour for the scene.
        */
        const ColourValue& getFogColour(void) const;

        /** Returns the fog start distance for the scene.
        */
        Real getFogStart(void) const;

        /** Returns the fog end distance for the scene.
        */
        Real getFogEnd(void) const;

        /** Returns the fog density for the scene.
        */
        Real getFogDensity(void) const;
        /// @}

        /// @name Billboard Sets
        /// @{
        /** Creates a new BillboardSet for use with this scene manager.

                This method creates a new BillboardSet which is registered with
                the SceneManager. The SceneManager will destroy this object when
                it shuts down or when the SceneManager::clearScene method is
                called, so the caller does not have to worry about destroying
                this object (in fact, it definitely should not do this).
            @par
                See the BillboardSet documentations for full details of the
                returned class.
            @param
                poolSize The initial size of the pool of billboards (see BillboardSet for more information)
            @see
                BillboardSet
        */
        BillboardSet* createBillboardSet(unsigned int poolSize = 20);

        /** @overload
            @copydoc createBillboardSet(unsigned int)
            @param
                name The name to give to this billboard set. Must be unique.
        */
        BillboardSet* createBillboardSet(const String& name, unsigned int poolSize = 20);

        /** Retrieves a pointer to the named BillboardSet.
        @note Throws an exception if the named instance does not exist
        */
        BillboardSet* getBillboardSet(const String& name) const;
        /** Returns whether a billboardset with the given name exists.
        */
        bool hasBillboardSet(const String& name) const;

        /** Removes & destroys an BillboardSet from the SceneManager.
            @warning
                Must only be done if the BillboardSet is not attached
                to a SceneNode. It may be safer to wait to clear the whole
                scene. If you are unsure, use clearScene.
        */
        void destroyBillboardSet(BillboardSet* set);

        /// @overload
        void destroyBillboardSet(const String& name);

        /** Removes & destroys all BillboardSets.
        @warning
        Again, use caution since no BillboardSet must be referred to
        elsewhere e.g. attached to a SceneNode otherwise a crash
        is likely. Use clearScene if you are unsure (it clears SceneNode
        entries too.)
        @see
        SceneManager::clearScene
        */
        void destroyAllBillboardSets(void);
        /// @}

        typedef MapIterator<AnimationList> AnimationIterator;
        /// @name Scene Node Animation
        /// @{
        /** Internal method for applying animations to scene nodes.
        @remarks
            Uses the internally stored AnimationState objects to apply animation to SceneNodes.
        */
        void _applySceneAnimations(void);

        /** Creates an animation which can be used to animate scene nodes.
        @remarks
            An animation is a collection of 'tracks' which over time change the position / orientation
            of Node objects. In this case, the animation will likely have tracks to modify the position
            / orientation of SceneNode objects, e.g. to make objects move along a path.
        @par
            You don't need to use an Animation object to move objects around - you can do it yourself
            using the methods of the Node in your FrameListener class. However, when you need relatively
            complex scripted animation, this is the class to use since it will interpolate between
            keyframes for you and generally make the whole process easier to manage.
        @par
            A single animation can affect multiple Node objects (each AnimationTrack affects a single Node).
            In addition, through animation blending a single Node can be affected by multiple animations,
            athough this is more useful when performing skeletal animation (see Skeleton::createAnimation).
        @par
            Note that whilst it uses the same classes, the animations created here are kept separate from the
            skeletal animations of meshes (each Skeleton owns those animations).
        @param name The name of the animation, must be unique within this SceneManager.
        @param length The total length of the animation.
        */
        Animation* createAnimation(const String& name, Real length);

        /** Looks up an Animation object previously created with createAnimation. 
        @note Throws an exception if the named instance does not exist
        */
        Animation* getAnimation(const String& name) const;
        /** Returns whether an animation with the given name exists.
        */
        bool hasAnimation(const String& name) const;

        /** Destroys an Animation. 
        @remarks
            You should ensure that none of your code is referencing this animation objects since the 
            memory will be freed.
        */
        void destroyAnimation(const String& name);

        /** Removes all animations created using this SceneManager. */
        void destroyAllAnimations(void);

        /** Create an AnimationState object for managing application of animations.
        @remarks
            You can create Animation objects for animating SceneNode obejcts using the
            createAnimation method. However, in order to actually apply those animations
            you have to call methods on Node and Animation in a particular order (namely
            Node::resetToInitialState and Animation::apply). To make this easier and to
            help track the current time position of animations, the AnimationState object
            is provided.
            So if you don't want to control animation application manually, call this method,
            update the returned object as you like every frame and let SceneManager apply 
            the animation state for you.
        @par
            Remember, AnimationState objects are disabled by default at creation time. 
            Turn them on when you want them using their setEnabled method.
        @par
            Note that any SceneNode affected by this automatic animation will have it's state
            reset to it's initial position before application of the animation. Unless specifically
            modified using Node::setInitialState the Node assumes it's initial state is at the
            origin. If you want the base state of the SceneNode to be elsewhere, make your changes
            to the node using the standard transform methods, then call setInitialState to 
            'bake' this reference position into the node.
        @par
            If the target of your animation is to be a generic AnimableValue, you
            should ensure that it has a base value set (unlike nodes this has no
            default). @see AnimableValue::setAsBaseValue.
        @param animName The name of an animation created already with createAnimation.
        */
        AnimationState* createAnimationState(const String& animName);

        /** Retrieves animation state as previously created using createAnimationState. 
        @note Throws an exception if the named instance does not exist
        */
        AnimationState* getAnimationState(const String& animName) const;
        /** Returns whether an animation state with the given name exists.
        */
        bool hasAnimationState(const String& name) const;

        /** Destroys an AnimationState. 
        @remarks
            You should ensure that none of your code is referencing this animation 
            state object since the memory will be freed.
        */
        void destroyAnimationState(const String& name);

        /** Removes all animation states created using this SceneManager. */
        void destroyAllAnimationStates(void);

        /** Returns a specialised MapIterator over all animations in the scene.
         * @deprecated use getAnimations() */
        OGRE_DEPRECATED AnimationIterator getAnimationIterator(void) {
            return AnimationIterator(mAnimationsList.begin(), mAnimationsList.end());
        }
        /** Returns a const version of the animation list.
        */
        const AnimationList& getAnimations() const { return mAnimationsList; }
        /** Returns a specialised MapIterator over all animation states in the scene.
         * @deprecated use getAnimationStates() */
        OGRE_DEPRECATED AnimationStateIterator getAnimationStateIterator(void)
        {
            return mAnimationStates.getAnimationStateIterator();
        }

        /** Returns a specialised Map over all animation states in the scene. */
        const AnimationStateMap& getAnimationStates() {
            return mAnimationStates.getAnimationStates();
        }
        /// @}

        /** Manual rendering method, for advanced users only.
        @remarks
            This method allows you to send rendering commands through the pipeline on
            demand, bypassing OGRE's normal world processing. You should only use this if you
            really know what you're doing; OGRE does lots of things for you that you really should
            let it do. However, there are times where it may be useful to have this manual interface,
            for example overlaying something on top of the scene rendered by OGRE.
        @par
            Because this is an instant rendering method, timing is important. The best 
            time to call it is from a RenderTargetListener event handler.
        @par
            Don't call this method a lot, it's designed for rare (1 or 2 times per frame) use. 
            Calling it regularly per frame will cause frame rate drops!
        @param rend A RenderOperation object describing the rendering op
        @param pass The Pass to use for this render
        @param vp Pointer to the viewport to render to, or 0 to use the current viewport
        @param worldMatrix The transform to apply from object to world space
        @param viewMatrix The transform to apply from world to view space
        @param projMatrix The transform to apply from view to screen space
        @param doBeginEndFrame If true, beginFrame() and endFrame() are called, 
            otherwise not. You should leave this as false if you are calling
            this within the main render loop.
        */
        void manualRender(RenderOperation* rend, Pass* pass, Viewport* vp,
            const Affine3& worldMatrix, const Affine3& viewMatrix, const Matrix4& projMatrix,
            bool doBeginEndFrame = false) ;

        /** Manual rendering method for rendering a single object. 
        @param rend The renderable to issue to the pipeline
        @param pass The pass to use
        @param vp Pointer to the viewport to render to, or 0 to use the existing viewport
        @param doBeginEndFrame If true, beginFrame() and endFrame() are called, 
        otherwise not. You should leave this as false if you are calling
        this within the main render loop.
        @param viewMatrix The transform to apply from world to view space
        @param projMatrix The transform to apply from view to screen space
        @param lightScissoringClipping If true, passes that have the getLightScissorEnabled
        and/or getLightClipPlanesEnabled flags will cause calculation and setting of 
        scissor rectangle and user clip planes. 
        @param doLightIteration If true, this method will issue the renderable to
        the pipeline possibly multiple times, if the pass indicates it should be
        done once per light
        @param manualLightList Only applicable if doLightIteration is false, this
        method allows you to pass in a previously determined set of lights
        which will be used for a single render of this object.
        */
        void manualRender(Renderable* rend, const Pass* pass, Viewport* vp,
            const Affine3& viewMatrix, const Matrix4& projMatrix, bool doBeginEndFrame = false, bool lightScissoringClipping = true,
            bool doLightIteration = true, const LightList* manualLightList = 0);

        /** Retrieves the internal render queue, for advanced users only.
        @remarks
            The render queue is mainly used internally to manage the scene object 
            rendering queue, it also exports some methods to allow advanced users 
            to configure the behavior of rendering process.
            Most methods provided by RenderQueue are supposed to be used 
            internally only, you should reference to the RenderQueue API for 
            more information. Do not access this directly unless you know what 
            you are doing.
        */
        RenderQueue* getRenderQueue(void);

        /** Registers a new RenderQueueListener which will be notified when render queues
            are processed.
        */
        void addRenderQueueListener(RenderQueueListener* newListener);

        /** Removes a listener previously added with addRenderQueueListener. */
        void removeRenderQueueListener(RenderQueueListener* delListener);
        
        /** Registers a new Render Object Listener which will be notified when rendering an object.     
        */
        void addRenderObjectListener(RenderObjectListener* newListener);
        /** Removes a listener previously added with addRenderObjectListener. */
        void removeRenderObjectListener(RenderObjectListener* delListener);

        /** Adds an item to the 'special case' render queue list.
        @remarks
            Normally all render queues are rendered, in their usual sequence, 
            only varying if a RenderQueueListener nominates for the queue to be 
            repeated or skipped. This method allows you to add a render queue to 
            a 'special case' list, which varies the behaviour. The effect of this
            list depends on the 'mode' in which this list is in, which might be
            to exclude these render queues, or to include them alone (excluding
            all other queues). This allows you to perform broad selective
            rendering without requiring a RenderQueueListener.
        @param qid The identifier of the queue which should be added to the
            special case list. Nothing happens if the queue is already in the list.
        */
        void addSpecialCaseRenderQueue(uint8 qid);
        /** Removes an item to the 'special case' render queue list.
        @see SceneManager::addSpecialCaseRenderQueue
        @param qid The identifier of the queue which should be removed from the
            special case list. Nothing happens if the queue is not in the list.
        */
        void removeSpecialCaseRenderQueue(uint8 qid);
        /** Clears the 'special case' render queue list.
        @see SceneManager::addSpecialCaseRenderQueue
        */
        void clearSpecialCaseRenderQueues(void);
        /** Sets the way the special case render queue list is processed.
        @see SceneManager::addSpecialCaseRenderQueue
        @param mode The mode of processing
        */
        void setSpecialCaseRenderQueueMode(SpecialCaseRenderQueueMode mode);
        /** Gets the way the special case render queue list is processed. */
        SpecialCaseRenderQueueMode getSpecialCaseRenderQueueMode(void);
        /** Returns whether or not the named queue will be rendered based on the
            current 'special case' render queue list and mode.
        @see SceneManager::addSpecialCaseRenderQueue
        @param qid The identifier of the queue which should be tested
        @return true if the queue will be rendered, false otherwise
        */
        bool isRenderQueueToBeProcessed(uint8 qid);

        /** Sets the render queue that the world geometry (if any) this SceneManager
            renders will be associated with.
        @remarks
            SceneManagers which provide 'world geometry' should place it in a 
            specialised render queue in order to make it possible to enable / 
            disable it easily using the addSpecialCaseRenderQueue method. Even 
            if the SceneManager does not use the render queues to render the 
            world geometry, it should still pick a queue to represent it's manual
            rendering, and check isRenderQueueToBeProcessed before rendering.
        @note
            Setting this may not affect the actual ordering of rendering the
            world geometry, if the world geometry is being rendered manually
            by the SceneManager. If the SceneManager feeds world geometry into
            the queues, however, the ordering will be affected. 
        */
        void setWorldGeometryRenderQueue(uint8 qid);
        /** Gets the render queue that the world geometry (if any) this SceneManager
            renders will be associated with.
        @remarks
            SceneManagers which provide 'world geometry' should place it in a 
            specialised render queue in order to make it possible to enable / 
            disable it easily using the addSpecialCaseRenderQueue method. Even 
            if the SceneManager does not use the render queues to render the 
            world geometry, it should still pick a queue to represent it's manual
            rendering, and check isRenderQueueToBeProcessed before rendering.
        */
        uint8 getWorldGeometryRenderQueue(void);

        /** Internal method for notifying the manager that a SceneNode is autotracking. */
        void _notifyAutotrackingSceneNode(SceneNode* node, bool autoTrack);

        /// @name Scene Queries
        /// @{
        /** Creates an AxisAlignedBoxSceneQuery for this scene manager. 
        @remarks
            This method creates a new instance of a query object for this scene manager, 
            for an axis aligned box region. See SceneQuery and AxisAlignedBoxSceneQuery 
            for full details.
        @par
            The instance returned from this method must be destroyed by calling
            SceneManager::destroyQuery when it is no longer required.
        @param box Details of the box which describes the region for this query.
        @param mask The query mask to apply to this query; can be used to filter out
            certain objects; see SceneQuery for details.
        */
        virtual AxisAlignedBoxSceneQuery* 
            createAABBQuery(const AxisAlignedBox& box, uint32 mask = 0xFFFFFFFF);
        /** Creates a SphereSceneQuery for this scene manager. 
        @remarks
            This method creates a new instance of a query object for this scene manager, 
            for a spherical region. See SceneQuery and SphereSceneQuery 
            for full details.
        @par
            The instance returned from this method must be destroyed by calling
            SceneManager::destroyQuery when it is no longer required.
        @param sphere Details of the sphere which describes the region for this query.
        @param mask The query mask to apply to this query; can be used to filter out
            certain objects; see SceneQuery for details.
        */
        virtual SphereSceneQuery* 
            createSphereQuery(const Sphere& sphere, uint32 mask = 0xFFFFFFFF);
        /** Creates a PlaneBoundedVolumeListSceneQuery for this scene manager. 
        @remarks
        This method creates a new instance of a query object for this scene manager, 
        for a region enclosed by a set of planes (normals pointing inwards). 
        See SceneQuery and PlaneBoundedVolumeListSceneQuery for full details.
        @par
        The instance returned from this method must be destroyed by calling
        SceneManager::destroyQuery when it is no longer required.
        @param volumes Details of the volumes which describe the region for this query.
        @param mask The query mask to apply to this query; can be used to filter out
        certain objects; see SceneQuery for details.
        */
        virtual PlaneBoundedVolumeListSceneQuery* 
            createPlaneBoundedVolumeQuery(const PlaneBoundedVolumeList& volumes, uint32 mask = 0xFFFFFFFF);


        /** Creates a RaySceneQuery for this scene manager. 
        @remarks
            This method creates a new instance of a query object for this scene manager, 
            looking for objects which fall along a ray. See SceneQuery and RaySceneQuery 
            for full details.
        @par
            The instance returned from this method must be destroyed by calling
            SceneManager::destroyQuery when it is no longer required.
        @param ray Details of the ray which describes the region for this query.
        @param mask The query mask to apply to this query; can be used to filter out
            certain objects; see SceneQuery for details.
        */
        virtual RaySceneQuery* 
            createRayQuery(const Ray& ray, uint32 mask = 0xFFFFFFFF);

        /** Creates an IntersectionSceneQuery for this scene manager. 
        @remarks
            This method creates a new instance of a query object for locating
            intersecting objects. See SceneQuery and IntersectionSceneQuery
            for full details.
        @par
            The instance returned from this method must be destroyed by calling
            SceneManager::destroyQuery when it is no longer required.
        @param mask The query mask to apply to this query; can be used to filter out
            certain objects; see SceneQuery for details.
        */
        virtual IntersectionSceneQuery* 
            createIntersectionQuery(uint32 mask = 0xFFFFFFFF);

        /** Destroys a scene query of any type. */
        void destroyQuery(SceneQuery* query);
        /// @}

        /// @name Shadow Setup
        /// @{
        /** Sets the general shadow technique to be used in this scene.
        @remarks   
            There are multiple ways to generate shadows in a scene, and each has 
            strengths and weaknesses. 
            <ul><li>Stencil-based approaches can be used to 
            draw very long, extreme shadows without loss of precision and the 'additive'
            version can correctly show the shadowing of complex effects like bump mapping
            because they physically exclude the light from those areas. However, the edges
            are very sharp and stencils cannot handle transparency, and they involve a 
            fair amount of CPU work in order to calculate the shadow volumes, especially
            when animated objects are involved.</li>
            <li>Texture-based approaches are good for handling transparency (they can, for
            example, correctly shadow a mesh which uses alpha to represent holes), and they
            require little CPU overhead, and can happily shadow geometry which is deformed
            by a vertex program, unlike stencil shadows. However, they have a fixed precision 
            which can introduce 'jaggies' at long range and have fillrate issues of their own.</li>
            </ul>
        @par
            We support 2 kinds of stencil shadows, and 2 kinds of texture-based shadows, and one
            simple decal approach. The 2 stencil approaches differ in the amount of multipass work 
            that is required - the modulative approach simply 'darkens' areas in shadow after the 
            main render, which is the least expensive, whilst the additive approach has to perform 
            a render per light and adds the cumulative effect, which is more expensive but more 
            accurate. The texture based shadows both work in roughly the same way, the only difference is
            that the shadowmap approach is slightly more accurate, but requires a more recent
            graphics card.
        @par
            Note that because mixing many shadow techniques can cause problems, only one technique
            is supported at once. Also, you should call this method at the start of the 
            scene setup. 
        @param technique The shadowing technique to use for the scene.
        */
        void setShadowTechnique(ShadowTechnique technique);
        
        /** Gets the current shadow technique. */
        ShadowTechnique getShadowTechnique(void) const { return mShadowRenderer.mShadowTechnique; }

        /** Enables / disables the rendering of debug information for shadows. */
        void setShowDebugShadows(bool debug) { mShadowRenderer.mDebugShadows = debug; }
        /** Are debug shadows shown? */
        bool getShowDebugShadows(void ) const { return mShadowRenderer.mDebugShadows; }

        /** Set the colour used to modulate areas in shadow. 
        @remarks This is only applicable for shadow techniques which involve 
            darkening the area in shadow, as opposed to masking out the light. 
            This colour provided is used as a modulative value to darken the
            areas.
        */
        void setShadowColour(const ColourValue& colour) { mShadowRenderer.setShadowColour(colour); }
        /** Get the colour used to modulate areas in shadow. 
        @remarks This is only applicable for shadow techniques which involve 
        darkening the area in shadow, as opposed to masking out the light. 
        This colour provided is used as a modulative value to darken the
        areas.
        */
        const ColourValue& getShadowColour(void) const;
        /** Sets the distance a shadow volume is extruded for a directional light.
        @remarks
            Although directional lights are essentially infinite, there are many
            reasons to limit the shadow extrusion distance to a finite number, 
            not least of which is compatibility with older cards (which do not
            support infinite positions), and shadow caster elimination.
        @par
            The default value is 10,000 world units. This does not apply to
            point lights or spotlights, since they extrude up to their 
            attenuation range.
        */
        void setShadowDirectionalLightExtrusionDistance(Real dist);
        /** Gets the distance a shadow volume is extruded for a directional light.
        */
        Real getShadowDirectionalLightExtrusionDistance(void) const;
        /** Sets the default maximum distance away from the camera that shadows
        will be visible. You have to call this function before you create lights
        or the default distance of zero will be used.
        @remarks
        Shadow techniques can be expensive, therefore it is a good idea
        to limit them to being rendered close to the camera if possible,
        and to skip the expense of rendering shadows for distance objects.
        This method allows you to set the distance at which shadows will no
        longer be rendered.
        @note
        Each shadow technique can interpret this subtely differently.
        For example, one technique may use this to eliminate casters,
        another might use it to attenuate the shadows themselves.
        You should tweak this value to suit your chosen shadow technique
        and scene setup.
        */
        void setShadowFarDistance(Real distance);
        /** Gets the default maximum distance away from the camera that shadows
        will be visible.
        */
        Real getShadowFarDistance(void) const
        { return mShadowRenderer.mDefaultShadowFarDist; }
        Real getShadowFarDistanceSquared(void) const
        { return mShadowRenderer.mDefaultShadowFarDistSquared; }

        /** Sets the maximum size of the index buffer used to render shadow
            primitives.
        @remarks
            This method allows you to tweak the size of the index buffer used
            to render shadow primitives (including stencil shadow volumes). The
            default size is 51,200 entries, which is 100k of GPU memory, or
            enough to render approximately 17,000 triangles. You can reduce this
            as long as you do not have any models / world geometry chunks which 
            could require more than the amount you set.
        @par
            The maximum number of triangles required to render a single shadow 
            volume (including light and dark caps when needed) will be 3x the 
            number of edges on the light silhouette, plus the number of 
            light-facing triangles. On average, half the 
            triangles will be facing toward the light, but the number of 
            triangles in the silhouette entirely depends on the mesh - 
            angular meshes will have a higher silhouette tris/mesh tris
            ratio than a smooth mesh. You can estimate the requirements for
            your particular mesh by rendering it alone in a scene with shadows
            enabled and a single light - rotate it or the light and make a note
            of how high the triangle count goes (remembering to subtract the 
            mesh triangle count)
        @param size The number of indexes; divide this by 3 to determine the
            number of triangles.
        */
        void setShadowIndexBufferSize(size_t size);
        /// Get the size of the shadow index buffer
        size_t getShadowIndexBufferSize(void) const { return mShadowRenderer.mShadowIndexBufferSize; }
        /** Get the shadow camera setup in use for all lights which don't have
            their own shadow camera setup.
        @see ShadowCameraSetup
        */
        const ShadowCameraSetupPtr& getShadowCameraSetup() const;

        /** Sets whether we should use an inifinite camera far plane
            when rendering stencil shadows.
        @remarks
            Stencil shadow coherency is very reliant on the shadow volume
            not being clipped by the far plane. If this clipping happens, you
            get a kind of 'negative' shadow effect. The best way to achieve
            coherency is to move the far plane of the camera out to infinity,
            thus preventing the far plane from clipping the shadow volumes.
            When combined with vertex program extrusion of the volume to
            infinity, which Ogre does when available, this results in very
            robust shadow volumes. For this reason, when you enable stencil
            shadows, Ogre automatically changes your camera settings to
            project to infinity if the card supports it. You can disable this
            behaviour if you like by calling this method; although you can
            never enable infinite projection if the card does not support it.
        @par
            If you disable infinite projection, or it is not available,
            you need to be far more careful with your light attenuation /
            directional light extrusion distances to avoid clipping artefacts
            at the far plane.
        @note
            Recent cards will generally support infinite far plane projection.
            However, we have found some cases where they do not, especially
            on Direct3D. There is no standard capability we can check to
            validate this, so we use some heuristics based on experience:
            <UL>
            <LI>OpenGL always seems to support it no matter what the card</LI>
            <LI>Direct3D on non-vertex program capable systems (including
            vertex program capable cards on Direct3D7) does not
            support it</LI>
            <LI>Direct3D on GeForce3 and GeForce4 Ti does not seem to support
            infinite projection<LI>
            </UL>
            Therefore in the RenderSystem implementation, we may veto the use
            of an infinite far plane based on these heuristics.
        */
        void setShadowUseInfiniteFarPlane(bool enable) {
            mShadowRenderer.mShadowUseInfiniteFarPlane = enable; }

        /** Is there a stencil shadow based shadowing technique in use? */
        bool isShadowTechniqueStencilBased(void) const
        { return (mShadowRenderer.mShadowTechnique & SHADOWDETAILTYPE_STENCIL) != 0; }
        /** Is there a texture shadow based shadowing technique in use? */
        bool isShadowTechniqueTextureBased(void) const
        { return (mShadowRenderer.mShadowTechnique & SHADOWDETAILTYPE_TEXTURE) != 0; }
        /** Is there a modulative shadowing technique in use? */
        bool isShadowTechniqueModulative(void) const
        { return (mShadowRenderer.mShadowTechnique & SHADOWDETAILTYPE_MODULATIVE) != 0; }
        /** Is there an additive shadowing technique in use? */
        bool isShadowTechniqueAdditive(void) const
        { return (mShadowRenderer.mShadowTechnique & SHADOWDETAILTYPE_ADDITIVE) != 0; }
        /** Is the shadow technique integrated into primary materials? */
        bool isShadowTechniqueIntegrated(void) const
        { return (mShadowRenderer.mShadowTechnique & SHADOWDETAILTYPE_INTEGRATED) != 0; }
        /** Is there any shadowing technique in use? */
        bool isShadowTechniqueInUse(void) const
        { return mShadowRenderer.mShadowTechnique != SHADOWTYPE_NONE; }
        /** Sets whether when using a built-in additive shadow mode, user clip
            planes should be used to restrict light rendering.
        */
        void setShadowUseLightClipPlanes(bool enabled) { mShadowRenderer.mShadowAdditiveLightClip = enabled; }
        /** Gets whether when using a built-in additive shadow mode, user clip
        planes should be used to restrict light rendering.
        */
        bool getShadowUseLightClipPlanes() const { return mShadowRenderer.mShadowAdditiveLightClip; }
        /// @}

        /// @name Shadow Texture Config
        /// @{

        /// Method for preparing shadow textures ready for use in a regular render
        /// Do not call manually unless before frame start or rendering is paused
        /// If lightList is not supplied, will render all lights in frustum
        virtual void prepareShadowTextures(Camera* cam, Viewport* vp, const LightList* lightList = 0);

        /** Set the size of the texture used for all texture-based shadows.
        @remarks
            The larger the shadow texture, the better the detail on 
            texture based shadows, but obviously this takes more memory.
            The default size is 512. Sizes must be a power of 2.
        @note This is the simple form, see setShadowTextureConfig for the more 
            complex form.
        */
        void setShadowTextureSize(unsigned short size) { mShadowRenderer.setShadowTextureSize(size); }

        /** Set the detailed configuration for a shadow texture.
        @param shadowIndex The index of the texture to configure, must be < the
            number of shadow textures setting
        @param width The width of the texture
        @param height The height of the texture
        @param format The pixel format of the texture
        @param fsaa The level of multisampling to use. Ignored if the device does not support it.
        @param depthBufferPoolId The pool # it should query the depth buffers from
        */
        void setShadowTextureConfig(size_t shadowIndex, uint16 width, uint16 height, PixelFormat format,
                                    uint16 fsaa = 0, uint16 depthBufferPoolId = 1)
        {
            mShadowRenderer.setShadowTextureConfig(shadowIndex, width, height, format, fsaa, depthBufferPoolId);
        }
        /** Set the detailed configuration for a shadow texture.
        @param shadowIndex The index of the texture to configure, must be < the
            number of shadow textures setting
        @param config Configuration structure
        */
        void setShadowTextureConfig(size_t shadowIndex, const ShadowTextureConfig& config)
        {
            mShadowRenderer.setShadowTextureConfig(shadowIndex, config);
        }

        /** Get the current shadow texture settings. */
        const ShadowTextureConfigList& getShadowTextureConfigList() const { return mShadowRenderer.mShadowTextureConfigList; }

        /// @deprecated use getShadowTextureConfigList
        OGRE_DEPRECATED ConstShadowTextureConfigIterator getShadowTextureConfigIterator() const;

        /** Set the pixel format of the textures used for texture-based shadows.
        @remarks
            By default, a colour texture is used (PF_X8R8G8B8) for texture shadows,
            but if you want to use more advanced texture shadow types you can 
            alter this. If you do, you will have to also call
            setShadowTextureCasterMaterial and setShadowTextureReceiverMaterial
            to provide shader-based materials to use these customised shadow
            texture formats.
        @note This is the simple form, see setShadowTextureConfig for the more 
            complex form.
        */
        void setShadowTexturePixelFormat(PixelFormat fmt)
        {
            mShadowRenderer.setShadowTexturePixelFormat(fmt);
        }
        /** Set the level of multisample AA of the textures used for texture-based shadows.
        @remarks
            By default, the level of multisample AA is zero.
        @note This is the simple form, see setShadowTextureConfig for the more 
            complex form.
        */
        void setShadowTextureFSAA(unsigned short fsaa) { mShadowRenderer.setShadowTextureFSAA(fsaa); }

        /** Set the number of textures allocated for texture-based shadows.
        @remarks
            The default number of textures assigned to deal with texture based
            shadows is 1; however this means you can only have one light casting
            shadows at the same time. You can increase this number in order to 
            make this more flexible, but be aware of the texture memory it will use.
        */
        void setShadowTextureCount(size_t count) { mShadowRenderer.setShadowTextureCount(count); }

        /// @deprecated use getShadowTextureConfigList
        OGRE_DEPRECATED size_t getShadowTextureCount(void) const {return mShadowRenderer.mShadowTextureConfigList.size(); }

        /** Set the number of shadow textures a light type uses.
        @remarks
            The default for all light types is 1. This means that each light uses only 1 shadow
            texture. Call this if you need more than 1 shadow texture per light, E.G. PSSM. 
        @note
            This feature only works with the Integrated shadow technique.
            Also remember to increase the total number of shadow textures you request
            appropriately (e.g. via setShadowTextureCount)!!
        */
        void setShadowTextureCountPerLightType(Light::LightTypes type, size_t count)
        { mShadowRenderer.mShadowTextureCountPerType[type] = count; }
        /// Get the number of shadow textures is assigned for the given light type.
        size_t getShadowTextureCountPerLightType(Light::LightTypes type) const
        {return mShadowRenderer.mShadowTextureCountPerType[type]; }

        /** Sets the size and count of textures used in texture-based shadows. 
        @see setShadowTextureSize and setShadowTextureCount for details, this
            method just allows you to change both at once, which can save on
            reallocation if the textures have already been created.
        @note This is the simple form, see setShadowTextureConfig for the more 
            complex form.
        */
        void setShadowTextureSettings(uint16 size, uint16 count, PixelFormat fmt = PF_BYTE_RGBA,
                                      uint16 fsaa = 0, uint16 depthBufferPoolId = 1)
        {
            mShadowRenderer.setShadowTextureSettings(size, count, fmt, fsaa, depthBufferPoolId);
        }

        /** Get a reference to the shadow texture currently in use at the given index.
        @note
            If you change shadow settings, this reference may no longer
            be correct, so be sure not to hold the returned reference over 
            texture shadow configuration changes.
        */
        const TexturePtr& getShadowTexture(size_t shadowIndex)
        {
            return mShadowRenderer.getShadowTexture(shadowIndex);
        }

        /** Sets the proportional distance which a texture shadow which is generated from a
            directional light will be offset into the camera view to make best use of texture space.

            When generating a shadow texture from a directional light, an approximation is used
            since it is not possible to render the entire scene to one texture. 
            The texture is projected onto an area centred on the camera, and is
            the shadow far distance * 2 in length (it is square). This wastes
            a lot of texture space outside the frustum though, so this offset allows
            you to move the texture in front of the camera more. However, be aware
            that this can cause a little shadow 'jittering' during rotation, and
            that if you move it too far then you'll start to get artefacts close 
            to the camera. The value is represented as a proportion of the shadow
            far distance, and the default is 0.6.
        */
        void setShadowDirLightTextureOffset(Real offset) { mShadowRenderer.mShadowTextureOffset = offset;}
        /** Gets the proportional distance which a texture shadow which is generated from a
        directional light will be offset into the camera view to make best use of texture space.
        */
        Real getShadowDirLightTextureOffset(void)  const { return mShadowRenderer.mShadowTextureOffset; }
        /** Sets the proportional distance at which texture shadows begin to fade out.
        @remarks
            To hide the edges where texture shadows end (in directional lights)
            Ogre will fade out the shadow in the distance. This value is a proportional
            distance of the entire shadow visibility distance at which the shadow
            begins to fade out. The default is 0.7
        */
        void setShadowTextureFadeStart(Real fadeStart)
        { mShadowRenderer.mShadowTextureFadeStart = fadeStart; }
        /** Sets the proportional distance at which texture shadows finish to fading out.
        @remarks
        To hide the edges where texture shadows end (in directional lights)
        Ogre will fade out the shadow in the distance. This value is a proportional
        distance of the entire shadow visibility distance at which the shadow
        is completely invisible. The default is 0.9.
        */
        void setShadowTextureFadeEnd(Real fadeEnd)
        { mShadowRenderer.mShadowTextureFadeEnd = fadeEnd; }

        /** Sets whether or not texture shadows should attempt to self-shadow.
        @remarks
            The default implementation of texture shadows uses a fixed-function 
            colour texture projection approach for maximum compatibility, and 
            as such cannot support self-shadowing. However, if you decide to 
            implement a more complex shadowing technique using the 
            setShadowTextureCasterMaterial and setShadowTextureReceiverMaterial 
            there is a possibility you may be able to support 
            self-shadowing (e.g by implementing a shader-based shadow map). In 
            this case you might want to enable this option.
        @param selfShadow Whether to attempt self-shadowing with texture shadows
        */
        void setShadowTextureSelfShadow(bool selfShadow);

        /// Gets whether or not texture shadows attempt to self-shadow.
        bool getShadowTextureSelfShadow(void) const
        { return mShadowRenderer.mShadowTextureSelfShadow; }
        /** Sets the default material to use for rendering shadow casters.
        @remarks
            By default shadow casters are rendered into the shadow texture using
            an automatically generated fixed-function pass. This allows basic
            projective texture shadows, but it's possible to use more advanced
            shadow techniques by overriding the caster and receiver materials, for
            example providing vertex and fragment programs to implement shadow
            maps.
        @par
            You can rely on the ambient light in the scene being set to the 
            requested texture shadow colour, if that's useful. 
        @note
            Individual objects may also override the vertex program in
            your default material if their materials include 
            shadow_caster_vertex_program_ref, shadow_receiver_vertex_program_ref
            shadow_caster_material entries, so if you use both make sure they are compatible.           
        @note
            Only a single pass is allowed in your material, although multiple
            techniques may be used for hardware fallback.
        */
        void setShadowTextureCasterMaterial(const MaterialPtr& mat)
        { mShadowRenderer.setShadowTextureCasterMaterial(mat); }

        /** Sets the default material to use for rendering shadow receivers.
        @remarks
            By default shadow receivers are rendered as a post-pass using basic
            modulation. This allows basic projective texture shadows, but it's 
            possible to use more advanced shadow techniques by overriding the 
            caster and receiver materials, for example providing vertex and 
            fragment programs to implement shadow maps.
        @par
            You can rely on texture unit 0 containing the shadow texture, and 
            for the unit to be set to use projective texturing from the light 
            (only useful if you're using fixed-function, which is unlikely; 
            otherwise you should rely on the texture_viewproj_matrix auto binding)
        @note
            Individual objects may also override the vertex program in
            your default material if their materials include 
            shadow_caster_vertex_program_ref shadow_receiver_vertex_program_ref
            shadow_receiver_material entries, so if you use both make sure they are compatible.
        @note
            Only a single pass is allowed in your material, although multiple
            techniques may be used for hardware fallback.
        */
        void setShadowTextureReceiverMaterial(const MaterialPtr& mat)
        { mShadowRenderer.setShadowTextureReceiverMaterial(mat); }

        /** Sets whether or not shadow casters should be rendered into shadow
            textures using their back faces rather than their front faces. 
        @remarks
            Rendering back faces rather than front faces into a shadow texture
            can help minimise depth comparison issues, if you're using depth
            shadowmapping. You will probably still need some biasing but you
            won't need as much. For solid objects the result is the same anyway,
            if you have objects with holes you may want to turn this option off.
            The default is to enable this option.
        */
        void setShadowCasterRenderBackFaces(bool bf) { mShadowRenderer.mShadowCasterRenderBackFaces = bf; }

        /** Gets whether or not shadow casters should be rendered into shadow
            textures using their back faces rather than their front faces. 
        */
        bool getShadowCasterRenderBackFaces() const { return mShadowRenderer.mShadowCasterRenderBackFaces; }

        /** Set the shadow camera setup to use for all lights which don't have
            their own shadow camera setup.
        @see ShadowCameraSetup
        */
        void setShadowCameraSetup(const ShadowCameraSetupPtr& shadowSetup);
        /// @}

        /** Sets the active compositor chain of the current scene being rendered.
            @note CompositorChain does this automatically, no need to call manually.
        */
        void _setActiveCompositorChain(CompositorChain* chain) { mActiveCompositorChain = chain; }

        /** Sets whether to use late material resolving or not. If set, materials will be resolved
            from the materials at the pass-setting stage and not at the render queue building stage.
            This is useful when the active material scheme during the render queue building stage
            is different from the one during the rendering stage.
        */
        void setLateMaterialResolving(bool isLate) { mLateMaterialResolving = isLate; }
        
        /** Gets whether using late material resolving or not.
            @see setLateMaterialResolving */
        bool isLateMaterialResolving() const { return mLateMaterialResolving; }

        /** Gets the active compositor chain of the current scene being rendered */
        CompositorChain* _getActiveCompositorChain() const { return mActiveCompositorChain; }

        /** Add a listener which will get called back on scene manager events.
        */
        void addListener(Listener* s);
        /** Remove a listener
        */
        void removeListener(Listener* s);

        /** Add a listener which will get called back on shadow texture events.
        */
        void addShadowTextureListener(ShadowTextureListener* s);
        /** Remove a listener
        */
        void removeShadowTextureListener(ShadowTextureListener* s);

        /// @name Static Geometry
        /// @{
        /** Creates a StaticGeometry instance suitable for use with this
            SceneManager.
        @remarks
            StaticGeometry is a way of batching up geometry into a more 
            efficient form at the expense of being able to move it. Please 
            read the StaticGeometry class documentation for full information.
        @param name The name to give the new object
        @return The new StaticGeometry instance
        */
        StaticGeometry* createStaticGeometry(const String& name);
        /** Retrieve a previously created StaticGeometry instance. 
        @note Throws an exception if the named instance does not exist
        */
        StaticGeometry* getStaticGeometry(const String& name) const;
        /** Returns whether a static geometry instance with the given name exists. */
        bool hasStaticGeometry(const String& name) const;
        /** Remove & destroy a StaticGeometry instance. */
        void destroyStaticGeometry(StaticGeometry* geom);
        /** Remove & destroy a StaticGeometry instance. */
        void destroyStaticGeometry(const String& name);
        /** Remove & destroy all StaticGeometry instances. */
        void destroyAllStaticGeometry(void);
        /// @}

        /// @name Instancing
        /// @{
        /** Creates an InstanceManager interface to create & manipulate instanced entities
            You need to call this function at least once before start calling createInstancedEntity
            to build up an instance based on the given mesh.
        @remarks
            Instancing is a way of batching up geometry into a much more 
            efficient form, but with some limitations, and still be able to move & animate it.
            Please see @ref InstanceManager class documentation for full information.
        @param customName Custom name for referencing. Must be unique
        @param meshName The mesh name the instances will be based upon
        @param groupName The resource name where the mesh lives
        @param technique Technique to use, which may be shader based, or hardware based.
        @param numInstancesPerBatch Suggested number of instances per batch. The actual number
        may end up being lower if the technique doesn't support having so many. It can't be zero
        @param flags Flags to pass to the InstanceManager see #InstanceManagerFlags
        @param subMeshIdx InstanceManager only supports using one submesh from the base mesh. This parameter
        says which submesh to pick (must be <= Mesh::getNumSubMeshes())
        @return The new InstanceManager instance
        */
        InstanceManager* createInstanceManager( const String &customName, const String &meshName,
                                                        const String &groupName,
                                                        InstanceManager::InstancingTechnique technique,
                                                        size_t numInstancesPerBatch, uint16 flags=0,
                                                        unsigned short subMeshIdx=0 );

        /** Retrieves an existing InstanceManager by it's name.
        @note Throws an exception if the named InstanceManager does not exist
        */
        InstanceManager* getInstanceManager( const String &managerName ) const;

        /** Returns whether an InstanceManager with the given name exists. */
        bool hasInstanceManager( const String &managerName ) const;

        /** Destroys an InstanceManager <b>if</b> it was created with createInstanceManager()
        @remarks
            Be sure you don't have any InstancedEntity referenced somewhere which was created with
            this manager, since it will become a dangling pointer.
        @param name Name of the manager to remove
        */
        void destroyInstanceManager( const String &name );
        void destroyInstanceManager( InstanceManager *instanceManager );

        void destroyAllInstanceManagers(void);

        /** @see InstanceManager::getMaxOrBestNumInstancesPerBatch
        @remarks
            If you've already created an InstanceManager, you can call it's
            getMaxOrBestNumInstancesPerBatch() function directly.
            Another (not recommended) way to know if the technique is unsupported is by creating
            an InstanceManager and use createInstancedEntity, which will return null pointer.
            The input parameter "numInstancesPerBatch" is a suggested value when using IM_VTFBESTFIT
            flag (in that case it should be non-zero)
        @return
            The ideal (or maximum, depending on flags) number of instances per batch for
            the given technique. Zero if technique is unsupported or errors were spotted
        */
        size_t getNumInstancesPerBatch( const String &meshName, const String &groupName,
                                                const String &materialName,
                                                InstanceManager::InstancingTechnique technique,
                                                size_t numInstancesPerBatch, uint16 flags=0,
                                                unsigned short subMeshIdx=0 );

        /** Creates an InstancedEntity based on an existing InstanceManager

        - Return value may be null if the InstanceManger technique isn't supported
        - Try to keep the number of entities with different materials <b>to a minimum</b>

        Alternatively you can call @ref InstanceManager::createInstancedEntity using the returned
        pointer from createInstanceManager()
        @see InstanceBatch
        @param materialName Material name 
        @param managerName Name of the instance manager
        @return An InstancedEntity ready to be attached to a SceneNode
        */
        InstancedEntity* createInstancedEntity( const String &materialName,
                                                        const String &managerName );

        /** Removes an InstancedEntity, @see SceneManager::createInstancedEntity &
            @see InstanceBatch::removeInstancedEntity
        @param instancedEntity Instance to remove
        */
        void destroyInstancedEntity( InstancedEntity *instancedEntity );

        /** Called by an InstanceManager when it has at least one InstanceBatch that needs their bounds
            to be updated for proper culling
            @param dirtyManager The manager with dirty batches to update
        */
        void _addDirtyInstanceManager( InstanceManager *dirtyManager );
        /// @}

        typedef MapIterator<MovableObjectMap> MovableObjectIterator;
        /// @name Movable Objects
        /// @{
        /** Create a movable object of the type specified.
        @remarks
            This is the generalised form of MovableObject creation where you can
            create a MovableObject of any specialised type generically, including
            any new types registered using plugins.
        @param name The name to give the object. Must be unique within type.
        @param typeName The type of object to create
        @param params Optional name/value pair list to give extra parameters to
            the created object.
        */
        MovableObject* createMovableObject(const String& name,
            const String& typeName, const NameValuePairList* params = 0);
        /// @overload
        MovableObject* createMovableObject(const String& typeName, const NameValuePairList* params = 0);
        /** Destroys a MovableObject with the name specified, of the type specified.
        @remarks
            The MovableObject will automatically detach itself from any nodes
            on destruction.
        */
        void destroyMovableObject(const String& name, const String& typeName);
        /** Destroys a MovableObject.
        @remarks
            The MovableObject will automatically detach itself from any nodes
            on destruction.
        */
        void destroyMovableObject(MovableObject* m);
        /** Destroy all MovableObjects of a given type. */
        void destroyAllMovableObjectsByType(const String& typeName);
        /** Destroy all MovableObjects. */
        void destroyAllMovableObjects(void);
        /** Get a reference to a previously created MovableObject. 
        @note Throws an exception if the named instance does not exist
        */
        MovableObject* getMovableObject(const String& name, const String& typeName) const;
        /** Returns whether a movable object instance with the given name exists. */
        bool hasMovableObject(const String& name, const String& typeName) const;
        /** Get all MovableObect instances of a given type.
        @note
            The iterator returned from this method is not thread safe, do not use this
            if you are creating or deleting objects of this type in another thread.
        */
        const MovableObjectMap& getMovableObjects(const String& typeName);

        /// @deprecated use getMovableObjects
        OGRE_DEPRECATED MovableObjectIterator getMovableObjectIterator(const String& typeName);
        /** Inject a MovableObject instance created externally.
        @remarks
            This method 'injects' a MovableObject instance created externally into
            the MovableObject instance registry held in the SceneManager. You
            might want to use this if you have a MovableObject which you don't
            want to register a factory for; for example a MovableObject which 
            cannot be generally constructed by clients. 
        @note
            It is important that the MovableObject has a unique name for the type,
            and that its getMovableType() method returns a proper type name.
        */
        void injectMovableObject(MovableObject* m);
        /** Extract a previously injected MovableObject.
        @remarks
            Essentially this does the same as destroyMovableObject, but only
            removes the instance from the internal lists, it does not attempt
            to destroy it.
        */
        void extractMovableObject(const String& name, const String& typeName);
        /// @overload
        void extractMovableObject(MovableObject* m);
        /** Extract all injected MovableObjects of a given type.
        @remarks
            Essentially this does the same as destroyAllMovableObjectsByType, 
            but only removes the instances from the internal lists, it does not 
            attempt to destroy them.
        */
        void extractAllMovableObjectsByType(const String& typeName);
        /// @}

        /** Sets a mask which is bitwise 'and'ed with objects own visibility masks
            to determine if the object is visible.
        @remarks
            Note that this is combined with any per-viewport visibility mask
            through an 'and' operation. @see Viewport::setVisibilityMask
        */
        void setVisibilityMask(uint32 vmask) { mVisibilityMask = vmask; }

        /** Gets a mask which is bitwise 'and'ed with objects own visibility masks
            to determine if the object is visible.
        */
        uint32 getVisibilityMask(void) { return mVisibilityMask; }

        /** Internal method for getting the combination between the global visibility
            mask and the per-viewport visibility mask.
        */
        uint32 _getCombinedVisibilityMask(void) const;

        /** Sets whether the SceneManager should search for visible objects, or
            whether they are being manually handled.
        @remarks
            This is an advanced function, you should not use this unless you know
            what you are doing.
        */
        void setFindVisibleObjects(bool find) { mFindVisibleObjects = find; }

        /** Gets whether the SceneManager should search for visible objects, or
            whether they are being manually handled.
        */
        bool getFindVisibleObjects(void) { return mFindVisibleObjects; }

        /** Set whether to automatically normalise normals on objects whenever they
            are scaled.
        @remarks
            Scaling can distort normals so the default behaviour is to compensate
            for this, but it has a cost. If you would prefer to manually manage 
            this, set this option to 'false' and use Pass::setNormaliseNormals
            only when needed.
        */
        void setNormaliseNormalsOnScale(bool n) { mNormaliseNormalsOnScale = n; }

        /** Get whether to automatically normalise normals on objects whenever they
            are scaled.
        */
        bool getNormaliseNormalsOnScale() const { return mNormaliseNormalsOnScale; }

        /** Set whether to automatically flip the culling mode on objects whenever they
            are negatively scaled.
        @remarks
            Negativelyl scaling an object has the effect of flipping the triangles, 
            so the culling mode should probably be inverted to deal with this. 
            If you would prefer to manually manage this, set this option to 'false' 
            and use different materials with Pass::setCullingMode set manually as needed.
        */
        void setFlipCullingOnNegativeScale(bool n) { mFlipCullingOnNegativeScale = n; }

        /** Get whether to automatically flip the culling mode on objects whenever they
            are negatively scaled.
        */
        bool getFlipCullingOnNegativeScale() const { return mFlipCullingOnNegativeScale; }

        /** Render something as if it came from the current queue.
        @param rend The renderable to issue to the pipeline
        @param pass The pass which is being used
        @param doLightIteration If true, this method will issue the renderable to
            the pipeline possibly multiple times, if the pass indicates it should be
            done once per light
        @param manualLightList Only applicable if doLightIteration is false, this
            method allows you to pass in a previously determined set of lights
            which will be used for a single render of this object.
        @param shadowDerivation If false, disables the derivation of shadow
            passes from original passes
         */
        void _injectRenderWithPass(Pass *pass, Renderable *rend, bool shadowDerivation = true,
            bool doLightIteration = false, const LightList* manualLightList = 0);

        /** Internal method for setting up the renderstate for a rendering pass.
            @param pass The Pass details to set.
            @param evenIfSuppressed unused
            @param shadowDerivation If false, disables the derivation of shadow
                passes from original passes
            @return
                A Pass object that was used instead of the one passed in, can
                happen when rendering shadow passes
        */
        const Pass* _setPass(const Pass* pass,
            bool evenIfSuppressed = false, bool shadowDerivation = true);
        
        /** Method to allow you to mark gpu parameters as dirty, causing them to 
            be updated according to the mask that you set when updateGpuProgramParameters is
            next called. Only really useful if you're controlling parameter state in 
            inner rendering loop callbacks.
            @param mask Some combination of GpuParamVariability which is bitwise OR'ed with the
                current dirty state.
        */
        void _markGpuParamsDirty(uint16 mask);

        /** Render the objects in a given queue group
        */
        void _renderQueueGroupObjects(RenderQueueGroup* group,
            QueuedRenderableCollection::OrganisationMode om);

        /** Advanced method for supplying an alternative visitor, used for parsing the
            render queues and sending the results to the renderer.
        @remarks
            You can use this method to insert your own implementation of the 
            QueuedRenderableVisitor interface, which receives calls as the queued
            renderables are parsed in a given order
            and are sent to the renderer. If you provide your own implementation of
            this visitor, you are responsible for either calling the rendersystem, 
            or passing the calls on to the base class implementation.
        @note
            Ownership is not taken of this pointer, you are still required to 
            delete it yourself once you're finished.
        @param visitor Your implementation of SceneMgrQueuedRenderableVisitor. 
            If you pass 0, the default implementation will be used.
        */
        void setQueuedRenderableVisitor(SceneMgrQueuedRenderableVisitor* visitor);

        /** Gets the current visitor object which processes queued renderables. */
        SceneMgrQueuedRenderableVisitor* getQueuedRenderableVisitor(void) const;


        /** Get the rendersystem subclass to which the output of this Scene Manager
            gets sent
        */
        RenderSystem *getDestinationRenderSystem();

        /** Gets the current viewport being rendered (advanced use only, only 
            valid during viewport update. */
        Viewport* getCurrentViewport(void) const { return mCurrentViewport; }

        /** Returns a visibility boundary box for a specific camera. */
        const VisibleObjectsBoundsInfo& getVisibleObjectsBoundsInfo(const Camera* cam) const;

        /**  Returns the shadow caster AAB for a specific light-camera combination */
        const VisibleObjectsBoundsInfo& getShadowCasterBoundsInfo(const Light* light, size_t iteration = 0) const;

        /** Add a level of detail listener. */
        void addLodListener(LodListener *listener);

        /**
        Remove a level of detail listener.
        @remarks
            Do not call from inside an LodListener callback method.
        */
        void removeLodListener(LodListener *listener);

        /** Notify that a movable object LOD change event has occurred. */
        void _notifyMovableObjectLodChanged(MovableObjectLodChangedEvent& evt);

        /** Notify that an entity mesh LOD change event has occurred. */
        void _notifyEntityMeshLodChanged(EntityMeshLodChangedEvent& evt);

        /** Notify that an entity material LOD change event has occurred. */
        void _notifyEntityMaterialLodChanged(EntityMaterialLodChangedEvent& evt);

        /** Handle LOD events. */
        void _handleLodEvents();

        IlluminationRenderStage _getCurrentRenderStage() {return mIlluminationStage;}

        const AutoParamDataSource* _getAutoParamDataSource() { return mAutoParamDataSource.get(); }
    };

    /// Interface for visualising debugging the SceneManager state
    class _OgreExport DebugDrawer : public SceneManager::Listener
    {
    public:
        virtual ~DebugDrawer() {}
        virtual void drawSceneNode(const SceneNode* node) = 0;
        virtual void drawBone(const Node* node) = 0;
        virtual void drawFrustum(const Frustum* frust) = 0;
    };

    /** Default implementation of IntersectionSceneQuery. */
    class _OgreExport DefaultIntersectionSceneQuery : 
        public IntersectionSceneQuery
    {
    public:
        DefaultIntersectionSceneQuery(SceneManager* creator);
        ~DefaultIntersectionSceneQuery();

        void execute(IntersectionSceneQueryListener* listener) override;
    };

    /** Default implementation of RaySceneQuery. */
    class _OgreExport DefaultRaySceneQuery : public RaySceneQuery
    {
    public:
        DefaultRaySceneQuery(SceneManager* creator);
        ~DefaultRaySceneQuery();

        void execute(RaySceneQueryListener* listener) override;
    };
    /** Default implementation of SphereSceneQuery. */
    class _OgreExport DefaultSphereSceneQuery : public SphereSceneQuery
    {
    public:
        DefaultSphereSceneQuery(SceneManager* creator);
        ~DefaultSphereSceneQuery();

        void execute(SceneQueryListener* listener) override;
    };
    /** Default implementation of PlaneBoundedVolumeListSceneQuery. */
    class _OgreExport DefaultPlaneBoundedVolumeListSceneQuery : public PlaneBoundedVolumeListSceneQuery
    {
    public:
        DefaultPlaneBoundedVolumeListSceneQuery(SceneManager* creator);
        ~DefaultPlaneBoundedVolumeListSceneQuery();

        void execute(SceneQueryListener* listener) override;
    };
    /** Default implementation of AxisAlignedBoxSceneQuery. */
    class _OgreExport DefaultAxisAlignedBoxSceneQuery : public AxisAlignedBoxSceneQuery
    {
    public:
        DefaultAxisAlignedBoxSceneQuery(SceneManager* creator);
        ~DefaultAxisAlignedBoxSceneQuery();

        void execute(SceneQueryListener* listener) override;
    };

    /** Structure containing information about a scene manager. */
    struct SceneManagerMetaData
    {
        /// A globally unique string identifying the scene manager type
        String typeName;
        /// Flag indicating whether world geometry is supported
        bool worldGeometrySupported;
    };



    /** Class which will create instances of a given SceneManager. */
    class _OgreExport SceneManagerFactory : public SceneMgtAlloc
    {
    protected:
        mutable SceneManagerMetaData mMetaData;
        mutable bool mMetaDataInit;
        /// Internal method to initialise the metadata, must be implemented
        virtual void initMetaData(void) const = 0;
    public:
        SceneManagerFactory() : mMetaDataInit(true) {}
        virtual ~SceneManagerFactory() {}
        /** Get information about the SceneManager type created by this factory. */
        virtual const SceneManagerMetaData& getMetaData(void) const 
        {
            if (mMetaDataInit)
            {
                initMetaData();
                mMetaDataInit = false;
            }
            return mMetaData; 
        }
        /** Create a new instance of a SceneManager.
        @remarks
        Don't call directly, use SceneManagerEnumerator::createSceneManager.
        */
        virtual SceneManager* createInstance(const String& instanceName) = 0;
        /** Destroy an instance of a SceneManager. */
        virtual void destroyInstance(SceneManager* instance) = 0;

    };

    /** @} */
    /** @} */


} // Namespace

#include "OgreHeaderSuffix.h"

#endif
