Occlusion culling

by Isaac on 04/21/2002 09:25, 3 messages, last message: 04/21/2002 22:26, 1099 views, last view: 04/21/2024 23:18

Could any of you tell me what technique of occlusion culling you used? Just curious.

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#1: the whole story is a bit long, but this is a summary:

by Aardappel on 04/21/2002 20:20

every frame, cube builds an "occlusion map", which is a cylindrical representation of at what distance the first occluder (wall) appears for every ray in your frustrum (up to 512 of them).

Then, when rendering a cube (it does this in quad-tree style so it can quickly reject large parts of the map), it finds the range of angles the cube is visible from the cube, and checks (conservatively) all angles in the occlusion map. If any of these are further away than the nearest point on the cube, it is visible, otherwise not.

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#2: oh and

by Aardappel on 04/21/2002 20:21

the building of the occlusion map happens by brute force ray tracing over the 2d world array, which thanks to the simplicity of the data is very fast.

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#3: Re: oh and

by Bascule on 04/21/2002 22:26, refers to #2

Oh....
I was just about to say that myself, but you beat me to it, Aard :P

My frustrum hurts just thinking about this sort of subject!

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