gluortho2d

With OpenGL, how can I use gluOrtho2D properly with default projection?

I'm trying to use gluOrtho2D with glutBitmapCharacter so that I can render text on the screen as well as my 3D objects. However, when I use glOrtho2D, my 3D objects dissapear; I assume this is because I'm not setting the projection back to the OpenGL/GLUT default, but I'm not really sure what that is. Anyway, this is the function I'm u...

gluOrtho2D and glViewport

Hi, I have an object defined in world coordinates, say a circle centered at (2,3) with radius 4. If I want the circle to not be distorted, to be entirely visible in the viewport and to be as big as possible within the viewport, how can I formulate a gluOrtho2D command to create a world window based on the aforementioned specs given that...