GL_AMD_draw_buffers_blend
http://www.opengl.org/registry/specs/gl/AMD/draw_buffers_blend.txt
GL_AMD_draw_buffers_blend
	void glBlendEquationIndexedAMD (GLuint buf, GLenum mode)
	void glBlendEquationSeparateIndexedAMD (GLuint buf, GLenum modeRGB, GLenum modeAlpha)
	void glBlendFuncIndexedAMD (GLuint buf, GLenum src, GLenum dst)
	void glBlendFuncSeparateIndexedAMD (GLuint buf, GLenum srcRGB, GLenum dstRGB, GLenum srcAlpha, GLenum dstAlpha)