   why GL_ALPHA_SCALE can not affect result
  glTexEnvf(GL_TEXTURE_ENV,GL_RGB_SCALE,m_fColorScale);glTexEnvf(GL_TEXTURE_ENV,GL_ALPHA_SCALE,m_fAlphaScale);I want to use the function to change scale of color and alpha, but it is not affect the out color.   
  Because that values aren't valid parameters to glTexEnv, are you checking GL errors?   ;  ha! I see, it must be in the range of 1.0 to 2.0   ;  thank you!   