Search found 10 matches
- Fri Nov 12, 2010 7:43 pm
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Is there anyway around quaternions for setting orientation?
- Replies: 2
- Views: 4090
Re: Is there anyway around quaternions for setting orientati
First ask yourself why you are inventing your own orientation representation (Directional vector + Up vector) rather than using an existing representation. There are many to choose from. If you don't feel like learning quaternions, consider using a 3x3 matrix. Your representation is very much like a...
- Tue Nov 02, 2010 1:39 am
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: btQuaternion clamping values and slerp question
- Replies: 3
- Views: 4819
Re: btQuaternion clamping values and slerp question
btQuat::angle actually measures the angle between the two 4d quaternions, not the angle you'd get if you converted the quat to an axis-angle format. An odd feature of quaternions is that every orientation is specified by two distinct quaternions: (x,y,z,w) and (-x,-y,-z,-w). These two quaternions ar...
- Fri Oct 29, 2010 7:13 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: allowedCcdPenetration questions
- Replies: 2
- Views: 3921
allowedCcdPenetration questions
A couple questions about allowedCcdPenetration. What is the intent of allowedCcdPenetration? Is it designed to improve gjk stability, or perhaps to allow the user to ignore grazing contacts? Or am I on the wrong track here? Also, what is the expected effect? I previously thought it was something lik...
- Thu Oct 14, 2010 3:06 am
- Forum: Release Announcements
- Topic: Sony Vector Math library and SIMD math library open sourced
- Replies: 5
- Views: 128881
Re: Sony Vector Math library and SIMD math library open sour
If the architecture, abi, compiler, and math library all cooperate, then returning a vector by value is cheap -- it goes in a register. Also, the less aliasing means more opportunities for the compiler to optimize. It's not OK for the api to change between the scalar and simd implementations (the ch...
- Tue Sep 28, 2010 11:52 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: btDispatcher::dispatchAllCollisionPairs
- Replies: 2
- Views: 4165
btDispatcher::dispatchAllCollisionPairs
Is there a subtle reason btDispatcher::dispatchAllCollisionPairs() takes a btDispatcher* parameter? void btCollisionDispatcher::dispatchAllCollisionPairs( btOverlappingPairCache* pairCache, const btDispatcherInfo& dispatchInfo, btDispatcher* dispatcher) { btCollisionPairCallback collisionCallbac...
- Wed Jun 16, 2010 6:44 pm
- Forum: General Bullet Physics Support and Feedback
- Topic: MOPP analogue
- Replies: 2
- Views: 3068
Re: MOPP analogue
* Use btCompoundShape with optional dbvt. CON: ray and sweep tests don't use the acceleration structure ( issue 25 ). Also, seems like a slight abuse of shapes; nobody will care about the combined inertia tensor, for example. Issue 25 looks easy for me to implement, but it _has_ been sitting around...
- Tue Jun 15, 2010 12:57 am
- Forum: General Bullet Physics Support and Feedback
- Topic: internalSetTemporaryCollisionShape necessary?
- Replies: 0
- Views: 1817
internalSetTemporaryCollisionShape necessary?
I'm looking at issue 25 now. I notice that rayTestSingle mutates the passed collisionObject by calling internalSetTemporaryCollisionShape. Is this still necessary any more? It looks like the btCompoundShape recursive case already explicitly passes down all the information it needs through collisionS...
- Sat Jun 12, 2010 12:40 am
- Forum: General Bullet Physics Support and Feedback
- Topic: MOPP analogue
- Replies: 2
- Views: 3068
MOPP analogue
We divide our large world into chunks and wrap all static collision for a chunk into a Hk MOPP. The broadphase contains only a couple static objects -- one for the MOPP, one with a custom heightfield shape. There seem to be a few possiblilities to do this this in Bullet. * Forget the container; batc...
- Wed Jun 02, 2010 12:29 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Pose matching with direct angular velocity control
- Replies: 3
- Views: 4602
Re: Pose matching with direct angular velocity control
Thanks! I can successfully create spring-like behavior, but I am having trouble figuring out exactly what parameters will result in the pose being 100% matched, 50% matched, and so on, so that I can control it in a precise way. If you want the object to move N% of the way to the goal during a fixed...
- Fri May 28, 2010 12:25 am
- Forum: General Bullet Physics Support and Feedback
- Topic: Quick Q: XDK and/or PS3 SDK project generation
- Replies: 1
- Views: 2446
Quick Q: XDK and/or PS3 SDK project generation
Is there some way to get CMake to generate project files for use with the XDK and/or PS3 SDK? Or is everyone who needs them writing them by hand?