improvements/bugfixes related to kinematic(animated) objects, synchronizeMotionStates

src/BulletCollision/CollisionDispatch/btCollisionObject.h

@@ -92,6 +92,11 @@ struct	btCollisionObject
 		return m_collisionFlags & CF_KINEMATIC_OJBECT;
 	}
 
+	inline bool		isStaticOrKinematicObject() const
+	{
+		return m_collisionFlags & (CF_KINEMATIC_OJBECT | CF_STATIC_OBJECT);
+	}
+
 	inline bool		hasContactResponse() const {
 		return !(m_collisionFlags & CF_NO_CONTACT_RESPONSE);
 	}

src/BulletCollision/CollisionDispatch/btSimulationIslandManager.cpp

@@ -237,6 +237,16 @@ void btSimulationIslandManager::buildAndProcessIslands(btDispatcher* dispatcher,
 		 if (((colObj0) && colObj0->GetActivationState() != ISLAND_SLEEPING) ||
 			((colObj1) && colObj1->GetActivationState() != ISLAND_SLEEPING))
 		{
+			//kinematic objects don't merge islands, but wake up all connected objects
+			if (colObj0->isKinematicObject() && colObj0->GetActivationState() != ISLAND_SLEEPING)
+			{
+				colObj1->SetActivationState(ACTIVE_TAG);
+			}
+			if (colObj1->isKinematicObject() && colObj1->GetActivationState() != ISLAND_SLEEPING)
+			{
+				colObj0->SetActivationState(ACTIVE_TAG);
+			}
+
 			//filtering for response
 			if (dispatcher->needsResponse(colObj0,colObj1))
 				islandmanifold.push_back(manifold);

src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp

@@ -145,7 +145,7 @@ void	btDiscreteDynamicsWorld::synchronizeMotionStates()
 			debugDrawObject(colObj->m_worldTransform,colObj->m_collisionShape,color);
 		}
 		btRigidBody* body = btRigidBody::upcast(colObj);
-		if (body && body->getMotionState())
+		if (body && body->getMotionState() && !body->isStaticOrKinematicObject())
 		{
 			if (body->GetActivationState() != ISLAND_SLEEPING)
 			{
@@ -524,7 +524,7 @@ void	btDiscreteDynamicsWorld::integrateTransforms(float timeStep)
 		btRigidBody* body = btRigidBody::upcast(colObj);
 		if (body)
 		{
-			if (body->IsActive() && (!body->isStaticObject()))
+			if (body->IsActive() && (!body->isStaticOrKinematicObject()))
 			{
 				body->predictIntegratedTransform(timeStep, predictedTrans);
 				body->proceedToTransform( predictedTrans);
@@ -545,7 +545,7 @@ void	btDiscreteDynamicsWorld::predictUnconstraintMotion(float timeStep)
 		btRigidBody* body = btRigidBody::upcast(colObj);
 		if (body)
 		{
-			if (!body->isStaticObject())
+			if (!body->isStaticOrKinematicObject())
 			{
 				if (body->IsActive())
 				{

src/BulletDynamics/Dynamics/btRigidBody.cpp

@@ -37,7 +37,6 @@ btRigidBody::btRigidBody(float mass, btMotionState* motionState, btCollisionShap
 	m_angularVelocity(0.f,0.f,0.f),
 	m_linearDamping(0.f),
 	m_angularDamping(0.5f),
-	m_kinematicTimeStep(0.f),
 	m_optionalMotionState(motionState),
 	m_contactSolverType(0),
 	m_frictionSolverType(0)
@@ -73,7 +72,6 @@ btRigidBody::btRigidBody( float mass,const btTransform& worldTransform,btCollisi
 	m_angularVelocity(0.f,0.f,0.f),
 	m_linearDamping(0.f),
 	m_angularDamping(0.5f),
-	m_kinematicTimeStep(0.f),
 	m_optionalMotionState(0),
 	m_contactSolverType(0),
 	m_frictionSolverType(0)
@@ -109,15 +107,17 @@ void btRigidBody::predictIntegratedTransform(btScalar timeStep,btTransform& pred
 
 void			btRigidBody::saveKinematicState(btScalar timeStep)
 {
-	
-	if (m_kinematicTimeStep)
+	//todo: clamp to some (user definable) safe minimum timestep, to limit maximum angular/linear velocities
+	if (timeStep != 0.f)
 	{
+		//if we use motionstate to synchronize world transforms, get the new kinematic/animated world transform
+		if (getMotionState())
+			getMotionState()->getWorldTransform(m_worldTransform);
 		btVector3 linVel,angVel;
-		btTransformUtil::calculateVelocity(m_interpolationWorldTransform,m_worldTransform,m_kinematicTimeStep,m_linearVelocity,m_angularVelocity);
+		btTransformUtil::calculateVelocity(m_interpolationWorldTransform,m_worldTransform,timeStep,m_linearVelocity,m_angularVelocity);
+		m_interpolationWorldTransform = m_worldTransform;
 		//printf("angular = %f %f %f\n",m_angularVelocity.getX(),m_angularVelocity.getY(),m_angularVelocity.getZ());
 	}
-	
-	m_kinematicTimeStep = timeStep;
 }
 	
 void	btRigidBody::getAabb(btVector3& aabbMin,btVector3& aabbMax) const
@@ -154,7 +154,7 @@ void btRigidBody::setDamping(btScalar lin_damping, btScalar ang_damping)
 
 void btRigidBody::applyForces(btScalar step)
 {
-	if (isStaticObject() || isKinematicObject())
+	if (isStaticOrKinematicObject())
 		return;
 	
 	applyCentralForce(m_gravity);	
@@ -229,7 +229,7 @@ void btRigidBody::updateInertiaTensor()
 
 void btRigidBody::integrateVelocities(btScalar step) 
 {
-	if (isStaticObject() || isKinematicObject())
+	if (isStaticOrKinematicObject())
 		return;
 
 	m_linearVelocity += m_totalForce * (m_inverseMass * step);

src/BulletDynamics/Dynamics/btRigidBody.h

@@ -56,7 +56,6 @@ class btRigidBody  : public btCollisionObject
 	btScalar		m_linearDamping;
 	btScalar		m_angularDamping;
 	
-	btScalar		m_kinematicTimeStep;
 
 	//m_optionalMotionState allows to automatic synchronize the world transform for active objects
 	btMotionState*	m_optionalMotionState;
@@ -148,7 +147,6 @@ public:
 	
   	void applyTorqueImpulse(const btVector3& torque)
 	{
-		if (!isStaticObject()&& !isKinematicObject())
 			m_angularVelocity += m_invInertiaTensorWorld * torque;
 	}