void gl_setpalettecolor(int c, int r, int g, int b);
void gl_setpalettecolors(int s, int n, void *sp);
void gl_setpalette(void *sp);
gl_setpalettecolors sets RGB values of n colors starting at s, which are stored as a table of groups of three bytes each at sp.
gl_setpalette is equivalent to setpalettecolors(0, 256, sp).
vga_ext_set(3) might change the range of the colors to be set to 0 - 255.
svgalib(7), vgagl(7), svgalib.conf(5), threedkit(7), testgl(1), vga_ext_set(3), gl_getpalette(3), gl_getpalettecolor(3), gl_getpalettecolors(3).
This manual page was edited by Michael Weller <email@example.com>. The exact source of the referenced demo as well as of the original documentation is unknown.
It is very likely that both are at least to some extent are due to Harm Hanemaayer <H.Hanemaayer@inter.nl.net>.
Occasionally this might be wrong. I hereby asked to be excused by the original author and will happily accept any additions or corrections to this first version of the svgalib manual.