Perspective Projection with OpenGL

Question

I am confused about perspective projection.

Here is the scenario that is confusing me. My frustrum\'s front plane is basically positioned at at positive z-axis and the b

Answer 1

So, in the above case what is the behavior that I should expect for the glFrustum with a negative as well as positive value for z. i.e. in this case -10 to +10.

Broken. You should expect the behavior to be broken.

The documentation is quite clear on this:

nearVal, farVal: Specify the distances to the near and far depth clipping planes. Both distances must be positive.

(emphasis added)

Passing a negative number (or zero) for these values will produce badness.