View Full Version : Help with glFrustumf

01-20-2015, 02:42 PM
The micro I am using supports opengl es 1.1. I am drawing lines and triangles in a square at 0 .. 1 (x,y axis) and 0 z axis.
When I set GL_PROJECTION matrix using glOrthof(0,1,0,1,-1,1) I can see what I have drawn.
When I use glFrustrumf(0,1,0,1,1,2) I see nothing. Should that not show the same as the orthographic view?
No matter what parameters I use in glFrustumf function I cannot see anything.
What Am I doing wrong? What should I set the frustum parameters to?

Thanks for any help.

01-20-2015, 04:50 PM
The orthographic projection has a Z range of -1..1, the perspective projection from 1..2. You're drawing at Z=0, which is in front of the near plane.

Note that you can't create a perspective projection where Z=0 is visible, as the near distance as to be positive.