I want to render text for my app. Normaly one would use glOrtho for pixel accurate quad rendering BUT in my app the textbox should move in the background (z).

Just imagine you have NPC´s (objects) in a video game and want to display their names above their heads. The names of the persons near to the camera should appear bigger and easier to read than the ones farther away.

What should I do? Where do I get an appropriate Projection Matrix? I can´t find anything regarding the problem online or in books.

Best regards, S.