rgl (version 0.99.16)

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)

Arguments

component

Which component(s)?

viewport

Lower left corner and size of desired region.

top

Whether to bring window to top before reading.

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.

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

# NOT RUN {
example(surface3d)
depth <- rgl.pixels(component = "depth")
if (length(depth) && is.matrix(depth)) # Protect against empty or single pixel windows
    contour(depth)
# }