GL_INGR_color_clamp http://www.opengl.org/registry/specs/gl/INGR/color_clamp.txt GL_INGR_color_clamp GL_RED_MIN_CLAMP_INGR 0x8560 GL_GREEN_MIN_CLAMP_INGR 0x8561 GL_BLUE_MIN_CLAMP_INGR 0x8562 GL_ALPHA_MIN_CLAMP_INGR 0x8563 GL_RED_MAX_CLAMP_INGR 0x8564 GL_GREEN_MAX_CLAMP_INGR 0x8565 GL_BLUE_MAX_CLAMP_INGR 0x8566 GL_ALPHA_MAX_CLAMP_INGR 0x8567