2D issue

It really depends how big your world is, and how much of it you can see at once.

E.g. if you can see 90% of the world at once, then culling might not be needed. But if you have a huge world and can only see 1% at once, then culling is definitely a necessity!

As a general rule, you will almost always want to implement a culling system. Even something simple like a bounding box or bounding circle test (less than dozen lines of code?) against the viewport can yield huge performance gains if you have a lot of objects. Initially it can just cull objects from rendering, but over time as your game gets more complex you might want to cull other things like certain game logic, animation, sounds, etc. The fastest code is that which you don't execute :)

I questioned this too.

Assuming:
1) The only way to check for "culling" is bounding box with the screen/viewport
2) Their is no game logic change depending on rendering for the object

Will their be a performance gain if you do it on the CPU instead of just sending it to OpenGL?

I suppose it might depends on whether your using immediate mode or display lists, arrays, buffers, etc.

Thanks for the replies. I think I am going to implement something very simple and compare it to the results of no culling. If the performance gain warrants, I'll put a little more work into making something faster. Thanks again.

Quote:

Original post by Boder Assuming: 1) The only way to check for "culling" is bounding box with the screen/viewport 2) Their is no game logic change depending on rendering for the object Will their be a performance gain if you do it on the CPU instead of just sending it to OpenGL?

In general, yes I find it helps performance to cull manually. Even if your culling is a brute force per-sprite bounding box it'll mean you have to create and send less vertex data and potentially less shader and texture switches. The only time I'd consider not culling is if you're doing an arena shooter or similar where there's no scrolling and practically everything is visible at the same time.