GL_EXT_blend_equation_separate
https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_blend_equation_separate.txt
GL_EXT_blend_equation_separate

	GL_BLEND_EQUATION_RGB_EXT 0x8009
	GL_BLEND_EQUATION_ALPHA_EXT 0x883D
	void glBlendEquationSeparateEXT (GLenum modeRGB, GLenum modeAlpha)