rgl (version 1.3.1)

rgl.pixels: Extract pixel information from window

Description

This function extracts single components of the pixel information from the topmost window.

Usage

rgl.pixels(component = c("red", "green", "blue"), 
        viewport = par3d("viewport"), top = TRUE)

Value

A vector, matrix or array containing the desired components. If one component is requested, a vector or matrix will be returned depending on the size of block requested (length 1 dimensions are dropped); if more, an array, whose last dimension is the list of components.

Arguments

component

Which component(s)?

viewport

Lower left corner and size of desired region.

top

Whether to bring window to top before reading.

Author

Duncan Murdoch

Details

The possible components are "red", "green", "blue", "alpha", "depth", and "luminance" (the sum of the three colors). All are scaled from 0 to 1.

Note that the luminance is kept below 1 by truncating the sum; this is the definition used for the GL_LUMINANCE component in OpenGL.

See Also

rgl.snapshot to write a copy to a file, demo("stereo") for functions that make use of this to draw a random dot stereogram and an anaglyph.

Examples

example(surface3d)
depth <- rgl.pixels(component = "depth")
if (length(depth) && is.matrix(depth)) # Protect against empty or single pixel windows
    contour(depth)