GL_NV_register_combiners2
https://www.khronos.org/registry/OpenGL/extensions/NV/NV_register_combiners2.txt
GL_NV_register_combiners2

	GL_PER_STAGE_CONSTANTS_NV 0x8535
	void glCombinerStageParameterfvNV (GLenum stage, GLenum pname, const GLfloat* params)
	void glGetCombinerStageParameterfvNV (GLenum stage, GLenum pname, GLfloat* params)
