title: OpenGL colorize filters
body: <p>I have an open GL quad that is rendered with a grayscale gradient. I would like to colorize it by applying a filter, something like:</p>
  
  <p>If color = 0,0,0 then set color to 255,255,255<br>
  If color = 0,0,1 then set color to 255,255,254<br>
  etc, or some scheme I decide on.</p>
  
  <p>Note the reason I do this in grayscale because the algorithm I'm using was designed to be drawn in grayscale and then colorized since the colors may not be known immediately.</p>
  
  <p>This would be similar to the java LookupOp <a href="http://download.oracle.com/javase/6/docs/api/java/awt/image/LookupOp.html" rel="nofollow">http://download.oracle.com/javase/6/docs/api/java/awt/image/LookupOp.html</a>.</p>
  
  <p>Is there a way to do this in openGL?</p>
  
  <p>thanks,<br>
  Jeff</p>