R: add primitive set shape

points3d {rgl} | R Documentation

## add primitive set shape

### Description

Adds a shape node to the current scene

### Usage

    points3d(x, y = NULL, z = NULL,  ...)
    lines3d(x, y = NULL, z = NULL,  ...)
    segments3d(x, y = NULL, z = NULL, ...)
    triangles3d(x, y = NULL, z = NULL, ...)
    quads3d(x, y = NULL, z = NULL, ...)

### Arguments

`x, y, z` | coordinates. Any reasonable way of defining the coordinates is acceptable. See the function `xyz.coords` for details.
`...` | Material properties (see `rgl.material`). For normals use `normals` and for texture coordinates use `texcoords`; see `rgl.primitive` for details.

### Details

The functions `points3d`, `lines3d`, `segments3d`, `triangles3d` and `quads3d` add points, joined lines, line segments, filled triangles or quadrilaterals to the plots. They correspond to the OpenGL types `GL_POINTS, GL_LINE_STRIP, GL_LINES, GL_TRIANGLES` and `GL_QUADS` respectively.

Points are taken in pairs by `segments3d`, triplets as the vertices of the triangles, and quadruplets for the quadrilaterals. Colors are applied vertex by vertex; if different at each end of a line segment, or each vertex of a polygon, the colors are blended over the extent of the object. Quadrilaterals must be entirely in one plane and convex, or the results are undefined.

These functions call the lower level functions `rgl.points`, `rgl.linestrips`, and so on, and are provided for convenience.

The appearance of the new objects are defined by the material properties. See `rgl.material` for details.

The two principal differences between the `rgl.*` functions and the `*3d` functions are that the former set all unspecified material properties to defaults, whereas the latter use current values as defaults; the former make persistent changes to material properties with each call, whereas the latter make temporary changes only for the duration of the call.

### Value

Each function returns the integer object ID of the shape that was added to the scene. These can be passed to `rgl.pop` to remove the object from the scene.

### Author(s)

Ming Chen and Duncan Murdoch

### Examples

    # Show 12 random vertices in various ways.

    M <- matrix(rnorm(36), 3, 12, dimnames = list(c('x', 'y', 'z'),
                                           rep(LETTERS[1:4], 3)))

    # Force 4-tuples to be convex in planes so that quads3d works.

    for (i in c(1, 5, 9)) {
        quad <- as.data.frame(M[, i + 0:3])
        coeffs <- runif(2, 0, 3)
        if (mean(coeffs) < 1) coeffs <- coeffs + 1 - mean(coeffs)
        quad$C <- with(quad, coeffs[1]*(B - A) + coeffs[2]*(D - A) + A)
        M[, i + 0:3] <- as.matrix(quad)
    }

    open3d()

    # Rows of M are x, y, z coords; transpose to plot

    M <- t(M)
    shift <- matrix(c(-3, 3, 0), 12, 3, byrow = TRUE)

    points3d(M)
    lines3d(M + shift)
    segments3d(M + 2*shift)
    triangles3d(M + 3*shift, col = 'red')
    quads3d(M + 4*shift, col = 'green')
    text3d(M + 5*shift, texts = 1:12)

    # Add labels

    shift <- outer(0:5, shift[1, ])
    shift[, 1] <- shift[, 1] + 3
    text3d(shift,
           texts = c('points3d', 'lines3d', 'segments3d',
             'triangles3d', 'quads3d', 'text3d'),
           adj = 0)
     rgl.bringtotop()

[Package rgl version 0.99.9 Index]