   X,-Y coordinates with opengl
  I am trying to make a 2-d game and i do not no how to manipulate the perspective and MODEL_VIEW types to get (0,0) in the upper left corner of the screen and (640x480) at the bottem right hand corner. Thanks you very much.Robert 
  This should work:glMatrixMode(GL_PROJECTION);glLoadIdentity();gluOrtho2D(0,639,479,0);glMatrixMode(GL_MODELVIEW);;  Thanks MAN You just propelled me into making my first opengl game. I already finished my first directx game. 