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Ray collision detection problem

Started by MultiVersal Gaming_001 Dec 14, 2002 at 10:54 PM 3 replies 300+ views

Original Post

Dec 14, 2002 at 10:54 PM

Is there a more efficient way to detect what polygon a ray intersects than testing the entire scene? Inversing the problem and testing the ray doesn''t help, as each polygon still has to be considered, and I''m using 700,000 polygon scenes minimum and that is far too slow for the framerate I''m seeking.(20) Bounding Boxes are ineffectual here, as I''m seeking precision for wat I''m doing. Thanks in advance. ChrisPugh

The Reindeer Effect

Dec 14, 2002 at 11:05 PM

Try using a BSP tree or something and you will be able to cut down bigtime by just calculating what nodes your ray goes through, then checking the poly''s in those nodes.

Not sure if this is the best way to do things though.

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MultiVersal Gaming_001

Dec 14, 2002 at 11:32 PM

Thank You very much. I needed a different angle on this problem for an opinion, as I didn''t have time to test. I asked, and didn''t get flamed or called a n00b, unlike so many messageboards. You all rock

Anyways, I''ve gone from 150,000 calculations on the cpu around 10,000. Big difference. Now a 1.7Ghz Athlon should be able to play my game (first person shooter, cutting edge tech, cutting edge art, 500-1000 character battles, etc) in 800X600, 40-60fps :D

Teknofreek

Dec 15, 2002 at 10:22 AM

Just to re-iterate what the others said, things like Bounding Boxes, Bounding Spheres, BSP trees, Quad/Oct-Trees, etc all are very useful mechanisms. Not to get accurate final testing mind you, but for early dismissal of objects/polys. Quick collision/intersection testing is all about figuring out as quickly as possible what things you DON''T have to an in-depth test on

-John

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