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View Full Version : Per-Vertex Lighting vs. Per-Pixel Lighting



New2CPP
06-12-2010, 01:46 PM
I'm very new to OpenGL and also to C++. I'm following a long tutorial on creating an OpenGL game engine. Its going pretty good so far, but one thing I've noticed is that the lighting looks really terrible sometimes. It uses per-vertex lighting so it ends up looking pretty ugly. I know that per-pixel lighting is more expensive to calculate, but I have a feeling it will look a lot nicer, and that it will be worth the performance hit.

I'm afraid my question is very vague but try to do your best to help me :). What are the coding differences between Per-Vertex lighting and per-Pixel lighting, that is to say: how can I change my existing code so it uses per-pixel calculations instead of per vertex? Is it just a few minor changes or does it require an entire re-working of the way the lighting rendering works?

Thanks in advance!

Dark Photon
06-12-2010, 01:52 PM
What are the coding differences between Per-Vertex lighting and per-Pixel lighting, that is to say: how can I change my existing code so it uses per-pixel calculations instead of per vertex?
Assuming you've already coded your lighting in a vertex shader, it's largely just pushing that lighting code into the fragment shader. Pretty simple.

For all the lighting equations, see the Lighting chapter in the OpenGL Programming Guide.

New2CPP
06-14-2010, 08:11 AM
Thanks!