GL_EXT_blend_minmax http://www.opengl.org/registry/specs/EXT/blend_minmax.txt GL_EXT_blend_minmax GL_FUNC_ADD_EXT 0x8006 GL_MIN_EXT 0x8007 GL_MAX_EXT 0x8008 GL_BLEND_EQUATION_EXT 0x8009 void glBlendEquationEXT (GLenum mode)