void	btContinuousDynamicsWorld::internalSingleStepSimulation( btScalar timeStep)
{
	
	startProfiling(timeStep);
	
	if(0 != m_internalPreTickCallback) {
		(*m_internalPreTickCallback)(this, timeStep);
	}


	///update aabbs information
	updateAabbs();
	//static int frame=0;
//	printf("frame %d\n",frame++);

	///apply gravity, predict motion
	predictUnconstraintMotion(timeStep);

	btDispatcherInfo& dispatchInfo = getDispatchInfo();

	dispatchInfo.m_timeStep = timeStep;
	dispatchInfo.m_stepCount = 0;
	dispatchInfo.m_debugDraw = getDebugDrawer();

	///perform collision detection
	performDiscreteCollisionDetection();

	calculateSimulationIslands();

	
	getSolverInfo().m_timeStep = timeStep;
	


	///solve contact and other joint constraints
	solveConstraints(getSolverInfo());
	
	///CallbackTriggers();
	calculateTimeOfImpacts(timeStep);

	btScalar toi = dispatchInfo.m_timeOfImpact;
//	if (toi < 1.f)
//		printf("toi = %f\n",toi);
	if (toi < 0.f)
		kdPrintf("toi = %f\n",toi);


	///integrate transforms
	integrateTransforms(timeStep * toi);

	///update vehicle simulation
	updateActions(timeStep);

	updateActivationState( timeStep );
	
	if(0 != m_internalTickCallback) {
		(*m_internalTickCallback)(this, timeStep);
	}
}
void	btDiscreteDynamicsWorld::internalSingleStepSimulation(btScalar timeStep)
{
	
	BT_PROFILE("internalSingleStepSimulation");

	if(0 != m_internalPreTickCallback) {
		(*m_internalPreTickCallback)(this, timeStep);
	}	

	///apply gravity, predict motion
	predictUnconstraintMotion(timeStep);

	btDispatcherInfo& dispatchInfo = getDispatchInfo();

	dispatchInfo.m_timeStep = timeStep;
	dispatchInfo.m_stepCount = 0;
	dispatchInfo.m_debugDraw = getDebugDrawer();


	///perform collision detection
	performDiscreteCollisionDetection();

	if (getDispatchInfo().m_useContinuous)
		addSpeculativeContacts(timeStep);


	calculateSimulationIslands();

	
	getSolverInfo().m_timeStep = timeStep;
	


	///solve contact and other joint constraints
	solveConstraints(getSolverInfo());
	
	///CallbackTriggers();

	///integrate transforms
	integrateTransforms(timeStep);

	///update vehicle simulation
	updateActions(timeStep);
	
	updateActivationState( timeStep );

	if(0 != m_internalTickCallback) {
		(*m_internalTickCallback)(this, timeStep);
	}	
}
int		btSimpleDynamicsWorld::stepSimulation( btScalar timeStep, int maxSubSteps, btScalar fixedTimeStep, btScalar fixedSubSteps)
{
	(void)fixedTimeStep;
	(void)maxSubSteps;
	(void)fixedSubSteps;


	///apply gravity, predict motion
	predictUnconstraintMotion(timeStep);

	btDispatcherInfo&	dispatchInfo = getDispatchInfo();
	dispatchInfo.m_timeStep = timeStep;
	dispatchInfo.m_stepCount = 0;
	dispatchInfo.m_debugDraw = getDebugDrawer();

	///perform collision detection
	performDiscreteCollisionDetection();

	///solve contact constraints
	int numManifolds = m_dispatcher1->getNumManifolds();
	if (numManifolds)
	{
		btPersistentManifold** manifoldPtr = ((btCollisionDispatcher*)m_dispatcher1)->getInternalManifoldPointer();
		
		btContactSolverInfo infoGlobal;
		infoGlobal.m_timeStep = timeStep;
		m_constraintSolver->prepareSolve(0, numManifolds);
		m_constraintSolver->solveGroup(&getCollisionObjectArray()[0], getNumCollisionObjects(), manifoldPtr, numManifolds,0,0, infoGlobal, m_debugDrawer, m_dispatcher1);
		m_constraintSolver->allSolved(infoGlobal, m_debugDrawer);
	}

	///integrate transforms
	integrateTransforms(timeStep);
		
	updateAabbs();

	synchronizeMotionStates();

	clearForces();

	return 1;

}