GL_NV_pixel_data_range
http://oss.sgi.com/projects/ogl-sample/registry/NV/pixel_data_range.txt
	GL_WRITE_PIXEL_DATA_RANGE_NV 0x8878
	GL_READ_PIXEL_DATA_RANGE_NV 0x8879
	GL_WRITE_PIXEL_DATA_RANGE_LENGTH_NV 0x887A
	GL_READ_PIXEL_DATA_RANGE_LENGTH_NV 0x887B
	GL_WRITE_PIXEL_DATA_RANGE_POINTER_NV 0x887C
	GL_READ_PIXEL_DATA_RANGE_POINTER_NV 0x887D
	void glFlushPixelDataRangeNV (GLenum target)
	void glPixelDataRangeNV (GLenum target, GLsizei length, void* pointer)