GL_EXT_texture_lod_bias
http://oss.sgi.com/projects/ogl-sample/registry/EXT/texture_lod_bias.txt
	GL_MAX_TEXTURE_LOD_BIAS_EXT 0x84FD
	GL_TEXTURE_FILTER_CONTROL_EXT 0x8500
	GL_TEXTURE_LOD_BIAS_EXT 0x8501