GL_SGIX_resample
http://oss.sgi.com/projects/ogl-sample/registry/SGIX/resample.txt
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