GL_EXT_cmyka http://www.opengl.org/registry/specs/gl/EXT/cmyka.txt GL_EXT_cmyka GL_CMYK_EXT 0x800C GL_CMYKA_EXT 0x800D GL_PACK_CMYK_HINT_EXT 0x800E GL_UNPACK_CMYK_HINT_EXT 0x800F