NVIDIA has extensions to make a custom framebuffer using "logical buffers" which are bitplanes! In fact, OpenGL uses bitplanes internally: http://oss.sgi.com/projects/ogl-sample/registry/EXT/framebuffer_object.txt (search for COLOR_ATTACHMENT) This means no conversion is necessary! At most all one would have to do is pad bitplanes with more zeroed-out bitplanes. Thus to display a 4-color palette, just add 6 extra empty bitplanes and set the first four colors in a 8bit palette!