Real-Time Physics Simulation Forum

I found vehicles are best simulated with a btMultiSphereShape that approximates the body, the rounded corners glance off walls and terrain better than cubes or the more angular convex hulls.

Xvfb and ffmpeg? I think I've also used the xorg dummy display driver on servers with a gpu to run more demanding opengl programs headless

use btCollisionObject::setWorldTransform if you want to alter position or orientation, example:

To avoid fragmentation I would precalculate and serialize all the btBvhTriangleMeshShape, then use pools of fixed sized allocations equal to the largest mesh and bvh and recycle the allocation when the object is streamed out. I think the serialization format is fairly simple but you would have to wr...

you probably want to grab the compound collision shape for the object and iterate over its children. if(fractureObject->getCollisionShape()->getShapeType() == COMPOUND_SHAPE_PROXYTYPE) { btCompoundShape* compoundShape = (btCompoundShape*)fractureObject->getCollisionShape(); for(int i = compoundShape...

your probably missing xlib development headers and stuff, On ubuntu and debian "apt-get install libx11-dev"?

Im not sure if this is the problem, but if you don't clear forces in your pre tick callback and have a variable frame rate the applied force can be doubled or more when frames are dropped. void preTickCallback(btDynamicsWorld *world, btScalar timeStep) { world->clearForces(); world->applyGravity(); ...

Can you paste a full stack trace? It might help a bit. Both the crashes you described though seem to have been caused by the btDbvtNode stack being shared across threads. Compiling bullet lib with BT_THREADSAFE should have created an array of 64 stacks. Double check your compiling and linking to the...

Really cool seeing the terrain rendering in action. I am curious whats the scale of your planet? I thought jittery floating point accuracy problems become apparent after a few dozen km, assuming 1.f = 1 meter.

btDbvtBroadphase::rayTest isn't thread safe by default. I think you need to build bullet with BT_THREADSAFE defined, possibly some other requirements for setup. check out lunkhound's thread he implemented it all http://www.bulletphysics.org/Bullet/php ... =9&t=10232

I would guess your convex primitives aabb overlaps all or most of the btBvhTriangleMeshShape even when not colliding, so all 10k triangles in overlapping volumes are being tested for collision against the primitive. A bvh would accelerate collision detection for something this complex if its scale w...

still stuck on this? I think you almost had it figure out. something like this should offset and shoot your bullet forward or backward. float power = 10.f; glm::vec3 forward = glm::mat3(glm::inverse(ViewMatrix)) * glm::vec3(0,0,1); glm::vec3 origin = cameraPos + forward; glm::vec3 vel = forward * po...

Cameras tend to be represented in opengl with a view matrix and projection matrix, create a 3x3 rotation matrix or a quaternion from the view matrix and multiply that by a forward vector like (0,0,1) to get a normal that points where the camera looks. Add this to offset your rigid body's creation lo...

gravity accelerates all objects equally https://www.youtube.com/watch?v=5C5_dOEyAfk

You could implement this with a btGhostObject , they maintain an array of overlapping objects, I think you would still have to perform a contactPairTest for each overlapping object to get btManifoldPoint where they touch. You might also find the btKinematicCharacterController useful too http://bulle...