Massive Raycasting speedup against Gimpact objects

[0xc0deface]

Hi.

I use bullet with btBvhTriangleMeshShape and btGImpactMeshShape for acurate raycasting in an editor like application.

I noticed that meshes approaching 2,000,000 tris would perform fine with btBvhTriangleMeshShape but grind to a halt with btGImpactMeshShape.

By that I mean the frame rate would plunge from 40fps to 3fps.

I found that btBvhTriangleMeshShape has a special case in btCollisionWorld::rayTestSingle which was letting it cast optimally where as btGImpactMeshShape was using the default case despite also being able to cast optimally.

I added a new function to btGImpactMeshShape called processAllTrianglesRay and made rayTestSingle use this for btGImpactMeshShapes. This boosted performance back up to the same level that btBvhTriangleMeshShape enjoys for raycasting; an order of magnitude improvement.

processAllTrianglesRay behaves the same as processAllTriangles however rather than using boxQuery internally it uses rayQuery.

I have attached a patch along with the final copies of the 3 files I changed.

I there are any problems that would stop this going into bullet let me know.

Thanks!

[Erwin Coumans]

That sounds good. Can you report the fix in the issue tracker?

https://code.google.com/p/bullet/issues/list

[0xc0deface]

Submit as issue 664. I attached the zip there also, and made the issue refer to this thread. Thanks!