Graphics.Rendering.OpenGL.Raw.EXT.TextureEnvCombine
gl_COMBINE
gl_COMBINE_RGB
gl_COMBINE_ALPHA
gl_SOURCE0_RGB
gl_SOURCE1_RGB
gl_SOURCE2_RGB
gl_SOURCE0_ALPHA
gl_SOURCE1_ALPHA
gl_SOURCE2_ALPHA
gl_OPERAND0_RGB
gl_OPERAND1_RGB
gl_OPERAND2_RGB
gl_OPERAND0_ALPHA
gl_OPERAND1_ALPHA
gl_OPERAND2_ALPHA
gl_RGB_SCALE
gl_ADD_SIGNED
gl_INTERPOLATE
gl_CONSTANT
gl_PRIMARY_COLOR
gl_PREVIOUS