   2D HUD
  I'm having a bit of trouble getting a 2D HUD (to display some text values) working correctly.Before drawing the 3D objects, I switch to glOrtho and draw some text. This works correctly and shows as expected. The issue I'm having is when I resize the screen.At the moment, to position the text, I use glRasterPos2f(x, y). I would like the text to stay at the same spot no matter what the window size (namely in the top-left corner) but as I resize the screen the text moves around and even disappears completely if resized enough.How can I rectify this?   
  How are you setting your arguments to glOrtho, is it invariant with resolution?For example if you use left = 0, right = 1, then drawing at 0.5 is always going to be at the center of the screen, and will appear to move if you resize the screen.If instead you give arguments like left = 0, right = ScreenWidth, then drawing at x = 5 will always be 5 pixels from the left of the screen, and won't move as you resize.Also you might want to consider drawing your hud after your 3d objects instead of before, if you're not careful your 3d objects could "pop through" or be drawn on top of the hud.   