GL_SGIX_resample http://www.opengl.org/registry/specs/SGIX/resample.txt GL_SGIX_resample GL_PACK_RESAMPLE_SGIX 0x842E GL_UNPACK_RESAMPLE_SGIX 0x842F GL_RESAMPLE_DECIMATE_SGIX 0x8430 GL_RESAMPLE_REPLICATE_SGIX 0x8433 GL_RESAMPLE_ZERO_FILL_SGIX 0x8434