   Using Alpha to change brightness
  Hi,I have drawn a square of a particulare colour and I want to use the Alpha to change its brightness (someone advised me to use this to emulate a flashing light).  I have enabled blending and switched off DEPTH_TEST.  I then do the following right before drawing a quad:  gl.Color( colour.R, colour.G, colour.B, colour.Alpha );  gl.BlendFunc(OpenGL.ALPHA, OpenGL.ONE);I have played around with this but the colour remains the same.  My intention is, when I have a backdrop, for the square to pulse in and out, but its made of a solid colour.Thanks for any help,D   