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View Full Version : (Semi OT) Frustum culling w/ axis aligned cubes?



dabeav
03-11-2003, 11:02 AM
Up till now, i have been working with odd shapes, thus frustum culling by testing the shapes pts versus the 6 faces of the frustum has worked well (common frustum culling). BUT, now i was wondering if there is a *Faster* method to do the same thing with a series of axis aligned same size cubes. I am attempting to make sort of an Octtree setup, but I would like a way to VERY quickly determin what im looking at, without having to test everything im not. Any suggestions?

Coriolis
03-11-2003, 11:29 AM
For an axis-aligned bounding box (not just cubes), you can precompute for each plane which of the six corners is the first to hit the plane as it moves toward the frustum from outside it. Then, you only check that one point, rather than all 8 corners of the box. This is comparable to the speed of checking a sphere; you don't have to do the radius comparison, but you do have one level of indirection to get the coordinates to plug into your plane equation.