GLenum internalformat, GLsizei width, GLenum format, GLenum
type, const GLvoid *table ) If target is GL_COLOR_TABLE,
GL_POST_CONVOLUTION_COLOR_TABLE, or
GL_POST_COLOR_MATRIX_COLOR_TABLE, glColorTable builds a color
lookup table from an array of pixels. The pixel array specified
by width, format, type, and table is extracted from memory and
processed just as if glDrawPixels were called, but processing
stops after the final expansion to RGBA is completed. The four
scale parameters and the four bias parameters that are defined
for the table are then used to scale and bias the R, G, B, and A
components of each pixel. (Use glColorTableParameter to set
these scale and bias parameters.) Next, the R, G, B, and A
values are clamped to the range [0, 1]. Each pixel is then
converted to the internal specified by internalformat. This
conversion simply maps the component values of the pixel (R, G,
B, and A) to the values included in the internal (red, green,
blue, alpha, luminance, and intensity). The mapping is as
follows