The narrow phase does not any real significant general tuning factors, especially since triangle-convex is a special case. Some of the more esoteric things like MPR depth refinement iteration limits could help, but you aren't going to get a significant speed up from that (maybe 10% at the cost of worse behavior).Which are the params which affect the Barrow phase, for tuning?
I'm not entirely sure what you mean here, but there's no way to reduce the number of triangles to test within a given pruned volume without reducing the actual number of triangles in that volume. (The engine is not using a uniform grid for the mesh acceleration structure, if that's what you're wondering; it uses a bounding volume hierarchy.)Reducing the size of the AABB Arras, should consume more memory but should reduce the number of triangles to test. Or not?
How long does it take? The Xbox360 is definitely slow, but it can handle 1000 boxes smashing together in orbit or 100 boxes all bunched up in a wall; it should be able to handle a couple of reasonably built cars without any issue.Using a squished cylinder works a lot better. But not enough.
If it's still taking something like 15 milliseconds per time step, something is likely going wrong that I can't divine directly from the information provided.
If it's more like 7 milliseconds and you just want to get it down below 5.5 ms so that it can run at 180hz, then that's a little closer to expecations. Still a bit on the slow side though, even for the Xbox360, but a combination of environmental details like excessive geometry density could conceivably slow it down that much.
With so few objects, multithreading is probably not helping at all. It has a small fixed cost due to the overhead of forking and joining repeatedly; disabling it could save a tiny bit of time. Maybe somewhere between 0 and 2 milliseconds on the Xbox.
Edit for edit:
An AABB will always have greater volume than the object it contains, unless the object it contains is an AABB. AABBs are used because they fit very well into efficient acceleration structures. Direct use of a paddle shape or other tighter volumes make hierarchy traversal and pruning more expensive.I know the size of the paddle, so that it isn't necessary that the AABB area is greater than the surface of the paddle, isn't it?
The library computes the tightest possible AABB for a shape. However, velocity-based expansion of an AABB is required for CCD and some query consistency, so the bounding box includes the swept motion from the current time step to the next time step.