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algorithmgraphicsocclusion

Occlusion algorithms collection

The occlusion algorithm is necessary in CAD and game industry. And they are different in the two industries I think. My questions are:

  1. What kind of occlusion algorithms are applied respectively in the two indurstries?
  2. and what is the difference?

I am working on CAD software development, and the occlusion algorithm we have adopted is - set the object identifier as its color (a integer) and then render the scene, at last, read the pixel to find out the visible objects. The performance is not so good, so I want to get some good ideas here. Thanks.

After read the anwsers, I want to clarify that the occlusion algorithms here means "occlusion culling" - find out visible surface or entities before send them into the pipeline.

With google, I have found a algorithm at gamasutra. Any other good ideas or findings? Thanks.

Solution

  • It stuck me that most of the answers so far only discuss image-order occlusion. I'm not entirely sure for CAD, but in games occlusion starts at a much higher level, using BSP trees, oct trees and/or portal rendering to quickly determine the objects that appear within the viewing frustum.