# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
# Copyright (c) 2008-2020 pyglet contributors
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
#  * Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
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#    the documentation and/or other materials provided with the
#    distribution.
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#    derived from this software without specific prior written
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# ----------------------------------------------------------------------------

from ctypes import *

import pyglet.lib
from pyglet.gl.lib import missing_function, decorate_function

from pyglet.util import asbytes

__all__ = ['link_GL', 'link_GLU', 'link_GLX']

gl_lib = pyglet.lib.load_library('GL')
glu_lib = pyglet.lib.load_library('GLU')

# Look for glXGetProcAddressARB extension, use it as fallback (for ATI fglrx and DRI drivers).
try:
    glXGetProcAddressARB = getattr(gl_lib, 'glXGetProcAddressARB')
    glXGetProcAddressARB.restype = POINTER(CFUNCTYPE(None))
    glXGetProcAddressARB.argtypes = [POINTER(c_ubyte)]
    _have_getprocaddress = True
except AttributeError:
    _have_getprocaddress = False


def link_GL(name, restype, argtypes, requires=None, suggestions=None):
    try:
        func = getattr(gl_lib, name)
        func.restype = restype
        func.argtypes = argtypes
        decorate_function(func, name)
        return func
    except AttributeError:
        if _have_getprocaddress:
            # Fallback if implemented but not in ABI
            bname = cast(pointer(create_string_buffer(asbytes(name))), POINTER(c_ubyte))
            addr = glXGetProcAddressARB(bname)
            if addr:
                ftype = CFUNCTYPE(*((restype,) + tuple(argtypes)))
                func = cast(addr, ftype)
                decorate_function(func, name)
                return func

    return missing_function(name, requires, suggestions)


link_GLX = link_GL


def link_GLU(name, restype, argtypes, requires=None, suggestions=None):
    try:
        func = getattr(glu_lib, name)
        func.restype = restype
        func.argtypes = argtypes
        decorate_function(func, name)
        return func
    except AttributeError:
        return missing_function(name, requires, suggestions)
