source: code/trunk/src/bullet/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp @ 2831

/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/


#include "btDiscreteDynamicsWorld.h"

//collision detection
#include "BulletCollision/CollisionDispatch/btCollisionDispatcher.h"
#include "BulletCollision/BroadphaseCollision/btSimpleBroadphase.h"
#include "BulletCollision/CollisionShapes/btCollisionShape.h"
#include "BulletCollision/CollisionDispatch/btSimulationIslandManager.h"
#include "LinearMath/btTransformUtil.h"
#include "LinearMath/btQuickprof.h"

//rigidbody & constraints
#include "BulletDynamics/Dynamics/btRigidBody.h"
#include "BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.h"
#include "BulletDynamics/ConstraintSolver/btContactSolverInfo.h"
#include "BulletDynamics/ConstraintSolver/btTypedConstraint.h"

//for debug rendering
#include "BulletCollision/CollisionShapes/btBoxShape.h"
#include "BulletCollision/CollisionShapes/btCapsuleShape.h"
#include "BulletCollision/CollisionShapes/btCompoundShape.h"
#include "BulletCollision/CollisionShapes/btConeShape.h"
#include "BulletCollision/CollisionShapes/btConvexTriangleMeshShape.h"
#include "BulletCollision/CollisionShapes/btCylinderShape.h"
#include "BulletCollision/CollisionShapes/btMultiSphereShape.h"
#include "BulletCollision/CollisionShapes/btPolyhedralConvexShape.h"
#include "BulletCollision/CollisionShapes/btSphereShape.h"
#include "BulletCollision/CollisionShapes/btTriangleCallback.h"
#include "BulletCollision/CollisionShapes/btTriangleMeshShape.h"
#include "BulletCollision/CollisionShapes/btStaticPlaneShape.h"
#include "LinearMath/btIDebugDraw.h"



//vehicle
#include "BulletDynamics/Vehicle/btRaycastVehicle.h"
#include "BulletDynamics/Vehicle/btVehicleRaycaster.h"
#include "BulletDynamics/Vehicle/btWheelInfo.h"
//character
#include "BulletDynamics/Character/btCharacterControllerInterface.h"

#include "LinearMath/btIDebugDraw.h"
#include "LinearMath/btQuickprof.h"
#include "LinearMath/btMotionState.h"





btDiscreteDynamicsWorld::btDiscreteDynamicsWorld(btDispatcher* dispatcher,btBroadphaseInterface* pairCache,btConstraintSolver* constraintSolver, btCollisionConfiguration* collisionConfiguration)
:btDynamicsWorld(dispatcher,pairCache,collisionConfiguration),
m_constraintSolver(constraintSolver),
m_gravity(0,-10,0),
m_localTime(btScalar(1.)/btScalar(60.)),
m_profileTimings(0)
{
        if (!m_constraintSolver)
        {
                void* mem = btAlignedAlloc(sizeof(btSequentialImpulseConstraintSolver),16);
                m_constraintSolver = new (mem) btSequentialImpulseConstraintSolver;
                m_ownsConstraintSolver = true;
        } else
        {
                m_ownsConstraintSolver = false;
        }

        {
                void* mem = btAlignedAlloc(sizeof(btSimulationIslandManager),16);
                m_islandManager = new (mem) btSimulationIslandManager();
        }

        m_ownsIslandManager = true;
}


btDiscreteDynamicsWorld::~btDiscreteDynamicsWorld()
{
        //only delete it when we created it
        if (m_ownsIslandManager)
        {
                m_islandManager->~btSimulationIslandManager();
                btAlignedFree( m_islandManager);
        }
        if (m_ownsConstraintSolver)
        {

                m_constraintSolver->~btConstraintSolver();
                btAlignedFree(m_constraintSolver);
        }
}

void    btDiscreteDynamicsWorld::saveKinematicState(btScalar timeStep)
{

        for (int i=0;i<m_collisionObjects.size();i++)
        {
                btCollisionObject* colObj = m_collisionObjects[i];
                btRigidBody* body = btRigidBody::upcast(colObj);
                if (body)
                {
                                btTransform predictedTrans;
                                if (body->getActivationState() != ISLAND_SLEEPING)
                                {
                                        if (body->isKinematicObject())
                                        {
                                                //to calculate velocities next frame
                                                body->saveKinematicState(timeStep);
                                        }
                                }
                }
        }
}

void    btDiscreteDynamicsWorld::debugDrawWorld()
{
        BT_PROFILE("debugDrawWorld");

        if (getDebugDrawer() && getDebugDrawer()->getDebugMode() & btIDebugDraw::DBG_DrawContactPoints)
        {
                int numManifolds = getDispatcher()->getNumManifolds();
                btVector3 color(0,0,0);
                for (int i=0;i<numManifolds;i++)
                {
                        btPersistentManifold* contactManifold = getDispatcher()->getManifoldByIndexInternal(i);
                        //btCollisionObject* obA = static_cast<btCollisionObject*>(contactManifold->getBody0());
                        //btCollisionObject* obB = static_cast<btCollisionObject*>(contactManifold->getBody1());

                        int numContacts = contactManifold->getNumContacts();
                        for (int j=0;j<numContacts;j++)
                        {
                                btManifoldPoint& cp = contactManifold->getContactPoint(j);
                                getDebugDrawer()->drawContactPoint(cp.m_positionWorldOnB,cp.m_normalWorldOnB,cp.getDistance(),cp.getLifeTime(),color);
                        }
                }
        }


        if (getDebugDrawer() && getDebugDrawer()->getDebugMode() & (btIDebugDraw::DBG_DrawWireframe | btIDebugDraw::DBG_DrawAabb))
        {
                int i;

                for (  i=0;i<m_collisionObjects.size();i++)
                {
                        btCollisionObject* colObj = m_collisionObjects[i];
                        if (getDebugDrawer() && getDebugDrawer()->getDebugMode() & btIDebugDraw::DBG_DrawWireframe)
                        {
                                btVector3 color(btScalar(255.),btScalar(255.),btScalar(255.));
                                switch(colObj->getActivationState())
                                {
                                case  ACTIVE_TAG:
                                        color = btVector3(btScalar(255.),btScalar(255.),btScalar(255.)); break;
                                case ISLAND_SLEEPING:
                                        color =  btVector3(btScalar(0.),btScalar(255.),btScalar(0.));break;
                                case WANTS_DEACTIVATION:
                                        color = btVector3(btScalar(0.),btScalar(255.),btScalar(255.));break;
                                case DISABLE_DEACTIVATION:
                                        color = btVector3(btScalar(255.),btScalar(0.),btScalar(0.));break;
                                case DISABLE_SIMULATION:
                                        color = btVector3(btScalar(255.),btScalar(255.),btScalar(0.));break;
                                default:
                                        {
                                                color = btVector3(btScalar(255.),btScalar(0.),btScalar(0.));
                                        }
                                };

                                debugDrawObject(colObj->getWorldTransform(),colObj->getCollisionShape(),color);
                        }
                        if (m_debugDrawer && (m_debugDrawer->getDebugMode() & btIDebugDraw::DBG_DrawAabb))
                        {
                                btVector3 minAabb,maxAabb;
                                btVector3 colorvec(1,0,0);
                                colObj->getCollisionShape()->getAabb(colObj->getWorldTransform(), minAabb,maxAabb);
                                m_debugDrawer->drawAabb(minAabb,maxAabb,colorvec);
                        }

                }
        
                for (  i=0;i<this->m_vehicles.size();i++)
                {
                        for (int v=0;v<m_vehicles[i]->getNumWheels();v++)
                        {
                                btVector3 wheelColor(0,255,255);
                                if (m_vehicles[i]->getWheelInfo(v).m_raycastInfo.m_isInContact)
                                {
                                        wheelColor.setValue(0,0,255);
                                } else
                                {
                                        wheelColor.setValue(255,0,255);
                                }
                
                                btVector3 wheelPosWS = m_vehicles[i]->getWheelInfo(v).m_worldTransform.getOrigin();

                                btVector3 axle = btVector3(     
                                        m_vehicles[i]->getWheelInfo(v).m_worldTransform.getBasis()[0][m_vehicles[i]->getRightAxis()],
                                        m_vehicles[i]->getWheelInfo(v).m_worldTransform.getBasis()[1][m_vehicles[i]->getRightAxis()],
                                        m_vehicles[i]->getWheelInfo(v).m_worldTransform.getBasis()[2][m_vehicles[i]->getRightAxis()]);


                                //m_vehicles[i]->getWheelInfo(v).m_raycastInfo.m_wheelAxleWS
                                //debug wheels (cylinders)
                                m_debugDrawer->drawLine(wheelPosWS,wheelPosWS+axle,wheelColor);
                                m_debugDrawer->drawLine(wheelPosWS,m_vehicles[i]->getWheelInfo(v).m_raycastInfo.m_contactPointWS,wheelColor);

                        }
                }
        }
}

void    btDiscreteDynamicsWorld::clearForces()
{
        ///@todo: iterate over awake simulation islands!
        for ( int i=0;i<m_collisionObjects.size();i++)
        {
                btCollisionObject* colObj = m_collisionObjects[i];
                
                btRigidBody* body = btRigidBody::upcast(colObj);
                if (body)
                {
                        body->clearForces();
                }
        }
}       

///apply gravity, call this once per timestep
void    btDiscreteDynamicsWorld::applyGravity()
{
        ///@todo: iterate over awake simulation islands!
        for ( int i=0;i<m_collisionObjects.size();i++)
        {
                btCollisionObject* colObj = m_collisionObjects[i];
                
                btRigidBody* body = btRigidBody::upcast(colObj);
                if (body && body->isActive())
                {
                        body->applyGravity();
                }
        }
}


void    btDiscreteDynamicsWorld::synchronizeSingleMotionState(btRigidBody* body)
{
        btAssert(body);

        if (body->getMotionState() && !body->isStaticOrKinematicObject())
        {
                //we need to call the update at least once, even for sleeping objects
                //otherwise the 'graphics' transform never updates properly
                ///@todo: add 'dirty' flag
                //if (body->getActivationState() != ISLAND_SLEEPING)
                {
                        btTransform interpolatedTransform;
                        btTransformUtil::integrateTransform(body->getInterpolationWorldTransform(),
                                body->getInterpolationLinearVelocity(),body->getInterpolationAngularVelocity(),m_localTime*body->getHitFraction(),interpolatedTransform);
                        body->getMotionState()->setWorldTransform(interpolatedTransform);
                }
        }
}


void    btDiscreteDynamicsWorld::synchronizeMotionStates()
{
        BT_PROFILE("synchronizeMotionStates");
        {
                //todo: iterate over awake simulation islands!
                for ( int i=0;i<m_collisionObjects.size();i++)
                {
                        btCollisionObject* colObj = m_collisionObjects[i];
                        
                        btRigidBody* body = btRigidBody::upcast(colObj);
                        if (body)
                                synchronizeSingleMotionState(body);
                }
        }

        if (getDebugDrawer() && getDebugDrawer()->getDebugMode() & btIDebugDraw::DBG_DrawWireframe)
        {
                for ( int i=0;i<this->m_vehicles.size();i++)
                {
                        for (int v=0;v<m_vehicles[i]->getNumWheels();v++)
                        {
                                //synchronize the wheels with the (interpolated) chassis worldtransform
                                m_vehicles[i]->updateWheelTransform(v,true);
                        }
                }
        }

}


int     btDiscreteDynamicsWorld::stepSimulation( btScalar timeStep,int maxSubSteps, btScalar fixedTimeStep)
{
        startProfiling(timeStep);

        BT_PROFILE("stepSimulation");

        int numSimulationSubSteps = 0;

        if (maxSubSteps)
        {
                //fixed timestep with interpolation
                m_localTime += timeStep;
                if (m_localTime >= fixedTimeStep)
                {
                        numSimulationSubSteps = int( m_localTime / fixedTimeStep);
                        m_localTime -= numSimulationSubSteps * fixedTimeStep;
                }
        } else
        {
                //variable timestep
                fixedTimeStep = timeStep;
                m_localTime = timeStep;
                if (btFuzzyZero(timeStep))
                {
                        numSimulationSubSteps = 0;
                        maxSubSteps = 0;
                } else
                {
                        numSimulationSubSteps = 1;
                        maxSubSteps = 1;
                }
        }

        //process some debugging flags
        if (getDebugDrawer())
        {
                gDisableDeactivation = (getDebugDrawer()->getDebugMode() & btIDebugDraw::DBG_NoDeactivation) != 0;
        }
        if (numSimulationSubSteps)
        {

                saveKinematicState(fixedTimeStep);

                applyGravity();

                //clamp the number of substeps, to prevent simulation grinding spiralling down to a halt
                int clampedSimulationSteps = (numSimulationSubSteps > maxSubSteps)? maxSubSteps : numSimulationSubSteps;

                for (int i=0;i<clampedSimulationSteps;i++)
                {
                        internalSingleStepSimulation(fixedTimeStep);
                        synchronizeMotionStates();
                }

        } 

        synchronizeMotionStates();

        clearForces();

#ifndef BT_NO_PROFILE
        CProfileManager::Increment_Frame_Counter();
#endif //BT_NO_PROFILE
        
        return numSimulationSubSteps;
}

void    btDiscreteDynamicsWorld::internalSingleStepSimulation(btScalar timeStep)
{
        
        BT_PROFILE("internalSingleStepSimulation");

        ///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();

        ///integrate transforms
        integrateTransforms(timeStep);

        ///update vehicle simulation
        updateVehicles(timeStep);
        
        updateCharacters(timeStep);

        updateActivationState( timeStep );

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

void    btDiscreteDynamicsWorld::setGravity(const btVector3& gravity)
{
        m_gravity = gravity;
        for ( int i=0;i<m_collisionObjects.size();i++)
        {
                btCollisionObject* colObj = m_collisionObjects[i];
                btRigidBody* body = btRigidBody::upcast(colObj);
                if (body)
                {
                        body->setGravity(gravity);
                }
        }
}

btVector3 btDiscreteDynamicsWorld::getGravity () const
{
        return m_gravity;
}


void    btDiscreteDynamicsWorld::removeRigidBody(btRigidBody* body)
{
        removeCollisionObject(body);
}

void    btDiscreteDynamicsWorld::addRigidBody(btRigidBody* body)
{
        if (!body->isStaticOrKinematicObject())
        {
                body->setGravity(m_gravity);
        }

        if (body->getCollisionShape())
        {
                bool isDynamic = !(body->isStaticObject() || body->isKinematicObject());
                short collisionFilterGroup = isDynamic? short(btBroadphaseProxy::DefaultFilter) : short(btBroadphaseProxy::StaticFilter);
                short collisionFilterMask = isDynamic?  short(btBroadphaseProxy::AllFilter) :   short(btBroadphaseProxy::AllFilter ^ btBroadphaseProxy::StaticFilter);

                addCollisionObject(body,collisionFilterGroup,collisionFilterMask);
        }
}

void    btDiscreteDynamicsWorld::addRigidBody(btRigidBody* body, short group, short mask)
{
        if (!body->isStaticOrKinematicObject())
        {
                body->setGravity(m_gravity);
        }

        if (body->getCollisionShape())
        {
                addCollisionObject(body,group,mask);
        }
}


void    btDiscreteDynamicsWorld::updateVehicles(btScalar timeStep)
{
        BT_PROFILE("updateVehicles");
        
        for ( int i=0;i<m_vehicles.size();i++)
        {
                btRaycastVehicle* vehicle = m_vehicles[i];
                vehicle->updateVehicle( timeStep);
        }
}

void    btDiscreteDynamicsWorld::updateCharacters(btScalar timeStep)
{
        BT_PROFILE("updateCharacters");
        
        for ( int i=0;i<m_characters.size();i++)
        {
                btCharacterControllerInterface* character = m_characters[i];
                character->preStep (this);
                character->playerStep (this,timeStep);
        }
}

        
        
void    btDiscreteDynamicsWorld::updateActivationState(btScalar timeStep)
{
        BT_PROFILE("updateActivationState");

        for ( int i=0;i<m_collisionObjects.size();i++)
        {
                btCollisionObject* colObj = m_collisionObjects[i];
                btRigidBody* body = btRigidBody::upcast(colObj);
                if (body)
                {
                        body->updateDeactivation(timeStep);

                        if (body->wantsSleeping())
                        {
                                if (body->isStaticOrKinematicObject())
                                {
                                        body->setActivationState(ISLAND_SLEEPING);
                                } else
                                {
                                        if (body->getActivationState() == ACTIVE_TAG)
                                                body->setActivationState( WANTS_DEACTIVATION );
                                        if (body->getActivationState() == ISLAND_SLEEPING) 
                                        {
                                                body->setAngularVelocity(btVector3(0,0,0));
                                                body->setLinearVelocity(btVector3(0,0,0));
                                        }

                                }
                        } else
                        {
                                if (body->getActivationState() != DISABLE_DEACTIVATION)
                                        body->setActivationState( ACTIVE_TAG );
                        }
                }
        }
}

void    btDiscreteDynamicsWorld::addConstraint(btTypedConstraint* constraint,bool disableCollisionsBetweenLinkedBodies)
{
        m_constraints.push_back(constraint);
        if (disableCollisionsBetweenLinkedBodies)
        {
                constraint->getRigidBodyA().addConstraintRef(constraint);
                constraint->getRigidBodyB().addConstraintRef(constraint);
        }
}

void    btDiscreteDynamicsWorld::removeConstraint(btTypedConstraint* constraint)
{
        m_constraints.remove(constraint);
        constraint->getRigidBodyA().removeConstraintRef(constraint);
        constraint->getRigidBodyB().removeConstraintRef(constraint);
}

void    btDiscreteDynamicsWorld::addVehicle(btRaycastVehicle* vehicle)
{
        m_vehicles.push_back(vehicle);
}

void    btDiscreteDynamicsWorld::removeVehicle(btRaycastVehicle* vehicle)
{
        m_vehicles.remove(vehicle);
}

void    btDiscreteDynamicsWorld::addCharacter(btCharacterControllerInterface* character)
{
        m_characters.push_back(character);
}

void    btDiscreteDynamicsWorld::removeCharacter(btCharacterControllerInterface* character)
{
        m_characters.remove(character);
}


SIMD_FORCE_INLINE       int     btGetConstraintIslandId(const btTypedConstraint* lhs)
{
        int islandId;
        
        const btCollisionObject& rcolObj0 = lhs->getRigidBodyA();
        const btCollisionObject& rcolObj1 = lhs->getRigidBodyB();
        islandId= rcolObj0.getIslandTag()>=0?rcolObj0.getIslandTag():rcolObj1.getIslandTag();
        return islandId;

}


class btSortConstraintOnIslandPredicate
{
        public:

                bool operator() ( const btTypedConstraint* lhs, const btTypedConstraint* rhs )
                {
                        int rIslandId0,lIslandId0;
                        rIslandId0 = btGetConstraintIslandId(rhs);
                        lIslandId0 = btGetConstraintIslandId(lhs);
                        return lIslandId0 < rIslandId0;
                }
};




void    btDiscreteDynamicsWorld::solveConstraints(btContactSolverInfo& solverInfo)
{
        BT_PROFILE("solveConstraints");
        
        struct InplaceSolverIslandCallback : public btSimulationIslandManager::IslandCallback
        {

                btContactSolverInfo&    m_solverInfo;
                btConstraintSolver*             m_solver;
                btTypedConstraint**             m_sortedConstraints;
                int                                             m_numConstraints;
                btIDebugDraw*                   m_debugDrawer;
                btStackAlloc*                   m_stackAlloc;
                btDispatcher*                   m_dispatcher;

                InplaceSolverIslandCallback(
                        btContactSolverInfo& solverInfo,
                        btConstraintSolver*     solver,
                        btTypedConstraint** sortedConstraints,
                        int     numConstraints,
                        btIDebugDraw*   debugDrawer,
                        btStackAlloc*                   stackAlloc,
                        btDispatcher* dispatcher)
                        :m_solverInfo(solverInfo),
                        m_solver(solver),
                        m_sortedConstraints(sortedConstraints),
                        m_numConstraints(numConstraints),
                        m_debugDrawer(debugDrawer),
                        m_stackAlloc(stackAlloc),
                        m_dispatcher(dispatcher)
                {

                }

                InplaceSolverIslandCallback& operator=(InplaceSolverIslandCallback& other)
                {
                        btAssert(0);
                        (void)other;
                        return *this;
                }
                virtual void    ProcessIsland(btCollisionObject** bodies,int numBodies,btPersistentManifold**   manifolds,int numManifolds, int islandId)
                {
                        if (islandId<0)
                        {
                                ///we don't split islands, so all constraints/contact manifolds/bodies are passed into the solver regardless the island id
                                m_solver->solveGroup( bodies,numBodies,manifolds, numManifolds,&m_sortedConstraints[0],m_numConstraints,m_solverInfo,m_debugDrawer,m_stackAlloc,m_dispatcher);
                        } else
                        {
                                        //also add all non-contact constraints/joints for this island
                                btTypedConstraint** startConstraint = 0;
                                int numCurConstraints = 0;
                                int i;
                                
                                //find the first constraint for this island
                                for (i=0;i<m_numConstraints;i++)
                                {
                                        if (btGetConstraintIslandId(m_sortedConstraints[i]) == islandId)
                                        {
                                                startConstraint = &m_sortedConstraints[i];
                                                break;
                                        }
                                }
                                //count the number of constraints in this island
                                for (;i<m_numConstraints;i++)
                                {
                                        if (btGetConstraintIslandId(m_sortedConstraints[i]) == islandId)
                                        {
                                                numCurConstraints++;
                                        }
                                }

                                ///only call solveGroup if there is some work: avoid virtual function call, its overhead can be excessive
                                if (numManifolds + numCurConstraints)
                                {
                                        m_solver->solveGroup( bodies,numBodies,manifolds, numManifolds,startConstraint,numCurConstraints,m_solverInfo,m_debugDrawer,m_stackAlloc,m_dispatcher);
                                }
                
                        }
                }

        };

        //sorted version of all btTypedConstraint, based on islandId
        btAlignedObjectArray<btTypedConstraint*>        sortedConstraints;
        sortedConstraints.resize( m_constraints.size());
        int i; 
        for (i=0;i<getNumConstraints();i++)
        {
                sortedConstraints[i] = m_constraints[i];
        }

//      assert(0);
                
        

        sortedConstraints.quickSort(btSortConstraintOnIslandPredicate());
        
        btTypedConstraint** constraintsPtr = getNumConstraints() ? &sortedConstraints[0] : 0;
        
        InplaceSolverIslandCallback     solverCallback( solverInfo,     m_constraintSolver, constraintsPtr,sortedConstraints.size(),    m_debugDrawer,m_stackAlloc,m_dispatcher1);
        
        m_constraintSolver->prepareSolve(getCollisionWorld()->getNumCollisionObjects(), getCollisionWorld()->getDispatcher()->getNumManifolds());
        
        /// solve all the constraints for this island
        m_islandManager->buildAndProcessIslands(getCollisionWorld()->getDispatcher(),getCollisionWorld(),&solverCallback);

        m_constraintSolver->allSolved(solverInfo, m_debugDrawer, m_stackAlloc);
}




void    btDiscreteDynamicsWorld::calculateSimulationIslands()
{
        BT_PROFILE("calculateSimulationIslands");

        getSimulationIslandManager()->updateActivationState(getCollisionWorld(),getCollisionWorld()->getDispatcher());

        {
                int i;
                int numConstraints = int(m_constraints.size());
                for (i=0;i< numConstraints ; i++ )
                {
                        btTypedConstraint* constraint = m_constraints[i];

                        const btRigidBody* colObj0 = &constraint->getRigidBodyA();
                        const btRigidBody* colObj1 = &constraint->getRigidBodyB();

                        if (((colObj0) && (!(colObj0)->isStaticOrKinematicObject())) &&
                                ((colObj1) && (!(colObj1)->isStaticOrKinematicObject())))
                        {
                                if (colObj0->isActive() || colObj1->isActive())
                                {

                                        getSimulationIslandManager()->getUnionFind().unite((colObj0)->getIslandTag(),
                                                (colObj1)->getIslandTag());
                                }
                        }
                }
        }

        //Store the island id in each body
        getSimulationIslandManager()->storeIslandActivationState(getCollisionWorld());

        
}


#include "BulletCollision/BroadphaseCollision/btCollisionAlgorithm.h"

class btClosestNotMeConvexResultCallback : public btCollisionWorld::ClosestConvexResultCallback
{
        btCollisionObject* m_me;
        btScalar m_allowedPenetration;
        btOverlappingPairCache* m_pairCache;


public:
        btClosestNotMeConvexResultCallback (btCollisionObject* me,const btVector3& fromA,const btVector3& toA,btOverlappingPairCache* pairCache) : 
          btCollisionWorld::ClosestConvexResultCallback(fromA,toA),
                m_allowedPenetration(0.0f),
                m_me(me),
                m_pairCache(pairCache)
        {
        }

        virtual btScalar addSingleResult(btCollisionWorld::LocalConvexResult& convexResult,bool normalInWorldSpace)
        {
                if (convexResult.m_hitCollisionObject == m_me)
                        return 1.0f;

                //ignore result if there is no contact response
                if(!convexResult.m_hitCollisionObject->hasContactResponse())
                        return 1.0f;

                btVector3 linVelA,linVelB;
                linVelA = m_convexToWorld-m_convexFromWorld;
                linVelB = btVector3(0,0,0);//toB.getOrigin()-fromB.getOrigin();

                btVector3 relativeVelocity = (linVelA-linVelB);
                //don't report time of impact for motion away from the contact normal (or causes minor penetration)
                if (convexResult.m_hitNormalLocal.dot(relativeVelocity)>=-m_allowedPenetration)
                        return 1.f;

                return ClosestConvexResultCallback::addSingleResult (convexResult, normalInWorldSpace);
        }

        virtual bool needsCollision(btBroadphaseProxy* proxy0) const
        {
                //don't collide with itself
                if (proxy0->m_clientObject == m_me)
                        return false;

                ///don't do CCD when the collision filters are not matching
                if (!ClosestConvexResultCallback::needsCollision(proxy0))
                        return false;

                ///don't do CCD when there are already contact points (touching contact/penetration)
                btAlignedObjectArray<btPersistentManifold*> manifoldArray;
                btBroadphasePair* collisionPair = m_pairCache->findPair(m_me->getBroadphaseHandle(),proxy0);
                if (collisionPair)
                {
                        if (collisionPair->m_algorithm)
                        {
                                manifoldArray.resize(0);
                                collisionPair->m_algorithm->getAllContactManifolds(manifoldArray);
                                for (int j=0;j<manifoldArray.size();j++)
                                {
                                        btPersistentManifold* manifold = manifoldArray[j];
                                        if (manifold->getNumContacts()>0)
                                                return false;
                                }
                        }
                }
                return true;
        }


};

///internal debugging variable. this value shouldn't be too high
int gNumClampedCcdMotions=0;

//#include "stdio.h"
void    btDiscreteDynamicsWorld::integrateTransforms(btScalar timeStep)
{
        BT_PROFILE("integrateTransforms");
        btTransform predictedTrans;
        for ( int i=0;i<m_collisionObjects.size();i++)
        {
                btCollisionObject* colObj = m_collisionObjects[i];
                btRigidBody* body = btRigidBody::upcast(colObj);
                if (body)
                {
                        body->setHitFraction(1.f);

                        if (body->isActive() && (!body->isStaticOrKinematicObject()))
                        {
                                body->predictIntegratedTransform(timeStep, predictedTrans);
                                btScalar squareMotion = (predictedTrans.getOrigin()-body->getWorldTransform().getOrigin()).length2();

                                if (body->getCcdSquareMotionThreshold() && body->getCcdSquareMotionThreshold() < squareMotion)
                                {
                                        BT_PROFILE("CCD motion clamping");
                                        if (body->getCollisionShape()->isConvex())
                                        {
                                                gNumClampedCcdMotions++;
                                                
                                                btClosestNotMeConvexResultCallback sweepResults(body,body->getWorldTransform().getOrigin(),predictedTrans.getOrigin(),getBroadphase()->getOverlappingPairCache());
                                                btConvexShape* convexShape = static_cast<btConvexShape*>(body->getCollisionShape());
                                                btSphereShape tmpSphere(body->getCcdSweptSphereRadius());//btConvexShape* convexShape = static_cast<btConvexShape*>(body->getCollisionShape());

                                                sweepResults.m_collisionFilterGroup = body->getBroadphaseProxy()->m_collisionFilterGroup;
                                                sweepResults.m_collisionFilterMask  = body->getBroadphaseProxy()->m_collisionFilterMask;

                                                convexSweepTest(&tmpSphere,body->getWorldTransform(),predictedTrans,sweepResults);
                                                if (sweepResults.hasHit() && (sweepResults.m_closestHitFraction < 1.f))
                                                {
                                                        body->setHitFraction(sweepResults.m_closestHitFraction);
                                                        body->predictIntegratedTransform(timeStep*body->getHitFraction(), predictedTrans);
                                                        body->setHitFraction(0.f);
//                                                      printf("clamped integration to hit fraction = %f\n",fraction);
                                                }
                                        }
                                }
                                
                                body->proceedToTransform( predictedTrans);
                        }
                }
        }
}





void    btDiscreteDynamicsWorld::predictUnconstraintMotion(btScalar timeStep)
{
        BT_PROFILE("predictUnconstraintMotion");
        for ( int i=0;i<m_collisionObjects.size();i++)
        {
                btCollisionObject* colObj = m_collisionObjects[i];
                btRigidBody* body = btRigidBody::upcast(colObj);
                if (body)
                {
                        if (!body->isStaticOrKinematicObject())
                        {
                                
                                body->integrateVelocities( timeStep);
                                //damping
                                body->applyDamping(timeStep);

                                body->predictIntegratedTransform(timeStep,body->getInterpolationWorldTransform());
                        }
                }
        }
}


void    btDiscreteDynamicsWorld::startProfiling(btScalar timeStep)
{
        (void)timeStep;

#ifndef BT_NO_PROFILE
        CProfileManager::Reset();
#endif //BT_NO_PROFILE

}




        

class DebugDrawcallback : public btTriangleCallback, public btInternalTriangleIndexCallback
{
        btIDebugDraw*   m_debugDrawer;
        btVector3       m_color;
        btTransform     m_worldTrans;

public:

        DebugDrawcallback(btIDebugDraw* debugDrawer,const btTransform& worldTrans,const btVector3& color) :
                m_debugDrawer(debugDrawer),
                m_color(color),
                m_worldTrans(worldTrans)
        {
        }

        virtual void internalProcessTriangleIndex(btVector3* triangle,int partId,int  triangleIndex)
        {
                processTriangle(triangle,partId,triangleIndex);
        }

        virtual void processTriangle(btVector3* triangle,int partId, int triangleIndex)
        {
                (void)partId;
                (void)triangleIndex;

                btVector3 wv0,wv1,wv2;
                wv0 = m_worldTrans*triangle[0];
                wv1 = m_worldTrans*triangle[1];
                wv2 = m_worldTrans*triangle[2];
                m_debugDrawer->drawLine(wv0,wv1,m_color);
                m_debugDrawer->drawLine(wv1,wv2,m_color);
                m_debugDrawer->drawLine(wv2,wv0,m_color);
        }
};

void btDiscreteDynamicsWorld::debugDrawSphere(btScalar radius, const btTransform& transform, const btVector3& color)
{
        btVector3 start = transform.getOrigin();

        const btVector3 xoffs = transform.getBasis() * btVector3(radius,0,0);
        const btVector3 yoffs = transform.getBasis() * btVector3(0,radius,0);
        const btVector3 zoffs = transform.getBasis() * btVector3(0,0,radius);

        // XY 
        getDebugDrawer()->drawLine(start-xoffs, start+yoffs, color);
        getDebugDrawer()->drawLine(start+yoffs, start+xoffs, color);
        getDebugDrawer()->drawLine(start+xoffs, start-yoffs, color);
        getDebugDrawer()->drawLine(start-yoffs, start-xoffs, color);

        // XZ
        getDebugDrawer()->drawLine(start-xoffs, start+zoffs, color);
        getDebugDrawer()->drawLine(start+zoffs, start+xoffs, color);
        getDebugDrawer()->drawLine(start+xoffs, start-zoffs, color);
        getDebugDrawer()->drawLine(start-zoffs, start-xoffs, color);

        // YZ
        getDebugDrawer()->drawLine(start-yoffs, start+zoffs, color);
        getDebugDrawer()->drawLine(start+zoffs, start+yoffs, color);
        getDebugDrawer()->drawLine(start+yoffs, start-zoffs, color);
        getDebugDrawer()->drawLine(start-zoffs, start-yoffs, color);
}

void btDiscreteDynamicsWorld::debugDrawObject(const btTransform& worldTransform, const btCollisionShape* shape, const btVector3& color)
{
        // Draw a small simplex at the center of the object
        {
                btVector3 start = worldTransform.getOrigin();
                getDebugDrawer()->drawLine(start, start+worldTransform.getBasis() * btVector3(1,0,0), btVector3(1,0,0));
                getDebugDrawer()->drawLine(start, start+worldTransform.getBasis() * btVector3(0,1,0), btVector3(0,1,0));
                getDebugDrawer()->drawLine(start, start+worldTransform.getBasis() * btVector3(0,0,1), btVector3(0,0,1));
        }

        if (shape->getShapeType() == COMPOUND_SHAPE_PROXYTYPE)
        {
                const btCompoundShape* compoundShape = static_cast<const btCompoundShape*>(shape);
                for (int i=compoundShape->getNumChildShapes()-1;i>=0;i--)
                {
                        btTransform childTrans = compoundShape->getChildTransform(i);
                        const btCollisionShape* colShape = compoundShape->getChildShape(i);
                        debugDrawObject(worldTransform*childTrans,colShape,color);
                }

        } else
        {
                switch (shape->getShapeType())
                {

                case SPHERE_SHAPE_PROXYTYPE:
                        {
                                const btSphereShape* sphereShape = static_cast<const btSphereShape*>(shape);
                                btScalar radius = sphereShape->getMargin();//radius doesn't include the margin, so draw with margin
                                
                                debugDrawSphere(radius, worldTransform, color);
                                break;
                        }
                case MULTI_SPHERE_SHAPE_PROXYTYPE:
                        {
                                const btMultiSphereShape* multiSphereShape = static_cast<const btMultiSphereShape*>(shape);

                                for (int i = multiSphereShape->getSphereCount()-1; i>=0;i--)
                                {
                                        btTransform childTransform = worldTransform;
                                        childTransform.getOrigin() += multiSphereShape->getSpherePosition(i);
                                        debugDrawSphere(multiSphereShape->getSphereRadius(i), childTransform, color);
                                }

                                break;
                        }
                case CAPSULE_SHAPE_PROXYTYPE:
                        {
                                const btCapsuleShape* capsuleShape = static_cast<const btCapsuleShape*>(shape);

                                btScalar radius = capsuleShape->getRadius();
                                btScalar halfHeight = capsuleShape->getHalfHeight();
                                
                                int upAxis = capsuleShape->getUpAxis();

                                
                                btVector3 capStart(0.f,0.f,0.f);
                                capStart[upAxis] = -halfHeight;

                                btVector3 capEnd(0.f,0.f,0.f);
                                capEnd[upAxis] = halfHeight;

                                // Draw the ends
                                {
                                        
                                        btTransform childTransform = worldTransform;
                                        childTransform.getOrigin() = worldTransform * capStart;
                                        debugDrawSphere(radius, childTransform, color);
                                }

                                {
                                        btTransform childTransform = worldTransform;
                                        childTransform.getOrigin() = worldTransform * capEnd;
                                        debugDrawSphere(radius, childTransform, color);
                                }

                                // Draw some additional lines
                                btVector3 start = worldTransform.getOrigin();

                                
                                capStart[(upAxis+1)%3] = radius;
                                capEnd[(upAxis+1)%3] = radius;
                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * capStart,start+worldTransform.getBasis() * capEnd, color);
                                capStart[(upAxis+1)%3] = -radius;
                                capEnd[(upAxis+1)%3] = -radius;
                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * capStart,start+worldTransform.getBasis() * capEnd, color);

                                capStart[(upAxis+1)%3] = 0.f;
                                capEnd[(upAxis+1)%3] = 0.f;

                                capStart[(upAxis+2)%3] = radius;
                                capEnd[(upAxis+2)%3] = radius;
                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * capStart,start+worldTransform.getBasis() * capEnd, color);
                                capStart[(upAxis+2)%3] = -radius;
                                capEnd[(upAxis+2)%3] = -radius;
                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * capStart,start+worldTransform.getBasis() * capEnd, color);

                                
                                break;
                        }
                case CONE_SHAPE_PROXYTYPE:
                        {
                                const btConeShape* coneShape = static_cast<const btConeShape*>(shape);
                                btScalar radius = coneShape->getRadius();//+coneShape->getMargin();
                                btScalar height = coneShape->getHeight();//+coneShape->getMargin();
                                btVector3 start = worldTransform.getOrigin();

                                int upAxis= coneShape->getConeUpIndex();
                                

                                btVector3       offsetHeight(0,0,0);
                                offsetHeight[upAxis] = height * btScalar(0.5);
                                btVector3       offsetRadius(0,0,0);
                                offsetRadius[(upAxis+1)%3] = radius;
                                btVector3       offset2Radius(0,0,0);
                                offset2Radius[(upAxis+2)%3] = radius;

                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * (offsetHeight),start+worldTransform.getBasis() * (-offsetHeight+offsetRadius),color);
                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * (offsetHeight),start+worldTransform.getBasis() * (-offsetHeight-offsetRadius),color);
                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * (offsetHeight),start+worldTransform.getBasis() * (-offsetHeight+offset2Radius),color);
                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * (offsetHeight),start+worldTransform.getBasis() * (-offsetHeight-offset2Radius),color);



                                break;

                        }
                case CYLINDER_SHAPE_PROXYTYPE:
                        {
                                const btCylinderShape* cylinder = static_cast<const btCylinderShape*>(shape);
                                int upAxis = cylinder->getUpAxis();
                                btScalar radius = cylinder->getRadius();
                                btScalar halfHeight = cylinder->getHalfExtentsWithMargin()[upAxis];
                                btVector3 start = worldTransform.getOrigin();
                                btVector3       offsetHeight(0,0,0);
                                offsetHeight[upAxis] = halfHeight;
                                btVector3       offsetRadius(0,0,0);
                                offsetRadius[(upAxis+1)%3] = radius;
                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * (offsetHeight+offsetRadius),start+worldTransform.getBasis() * (-offsetHeight+offsetRadius),color);
                                getDebugDrawer()->drawLine(start+worldTransform.getBasis() * (offsetHeight-offsetRadius),start+worldTransform.getBasis() * (-offsetHeight-offsetRadius),color);
                                break;
                        }

                        case STATIC_PLANE_PROXYTYPE:
                                {
                                        const btStaticPlaneShape* staticPlaneShape = static_cast<const btStaticPlaneShape*>(shape);
                                        btScalar planeConst = staticPlaneShape->getPlaneConstant();
                                        const btVector3& planeNormal = staticPlaneShape->getPlaneNormal();
                                        btVector3 planeOrigin = planeNormal * planeConst;
                                        btVector3 vec0,vec1;
                                        btPlaneSpace1(planeNormal,vec0,vec1);
                                        btScalar vecLen = 100.f;
                                        btVector3 pt0 = planeOrigin + vec0*vecLen;
                                        btVector3 pt1 = planeOrigin - vec0*vecLen;
                                        btVector3 pt2 = planeOrigin + vec1*vecLen;
                                        btVector3 pt3 = planeOrigin - vec1*vecLen;
                                        getDebugDrawer()->drawLine(worldTransform*pt0,worldTransform*pt1,color);
                                        getDebugDrawer()->drawLine(worldTransform*pt2,worldTransform*pt3,color);
                                        break;

                                }
                default:
                        {

                                if (shape->isConcave())
                                {
                                        btConcaveShape* concaveMesh = (btConcaveShape*) shape;
                                        
                                        ///@todo pass camera, for some culling? no -> we are not a graphics lib
                                        btVector3 aabbMax(btScalar(1e30),btScalar(1e30),btScalar(1e30));
                                        btVector3 aabbMin(btScalar(-1e30),btScalar(-1e30),btScalar(-1e30));

                                        DebugDrawcallback drawCallback(getDebugDrawer(),worldTransform,color);
                                        concaveMesh->processAllTriangles(&drawCallback,aabbMin,aabbMax);

                                }

                                if (shape->getShapeType() == CONVEX_TRIANGLEMESH_SHAPE_PROXYTYPE)
                                {
                                        btConvexTriangleMeshShape* convexMesh = (btConvexTriangleMeshShape*) shape;
                                        //todo: pass camera for some culling                    
                                        btVector3 aabbMax(btScalar(1e30),btScalar(1e30),btScalar(1e30));
                                        btVector3 aabbMin(btScalar(-1e30),btScalar(-1e30),btScalar(-1e30));
                                        //DebugDrawcallback drawCallback;
                                        DebugDrawcallback drawCallback(getDebugDrawer(),worldTransform,color);
                                        convexMesh->getMeshInterface()->InternalProcessAllTriangles(&drawCallback,aabbMin,aabbMax);
                                }


                                /// for polyhedral shapes
                                if (shape->isPolyhedral())
                                {
                                        btPolyhedralConvexShape* polyshape = (btPolyhedralConvexShape*) shape;

                                        int i;
                                        for (i=0;i<polyshape->getNumEdges();i++)
                                        {
                                                btVector3 a,b;
                                                polyshape->getEdge(i,a,b);
                                                btVector3 wa = worldTransform * a;
                                                btVector3 wb = worldTransform * b;
                                                getDebugDrawer()->drawLine(wa,wb,color);

                                        }

                                        
                                }
                        }
                }
        }
}


void    btDiscreteDynamicsWorld::setConstraintSolver(btConstraintSolver* solver)
{
        if (m_ownsConstraintSolver)
        {
                btAlignedFree( m_constraintSolver);
        }
        m_ownsConstraintSolver = false;
        m_constraintSolver = solver;
}

btConstraintSolver* btDiscreteDynamicsWorld::getConstraintSolver()
{
        return m_constraintSolver;
}


int             btDiscreteDynamicsWorld::getNumConstraints() const
{
        return int(m_constraints.size());
}
btTypedConstraint* btDiscreteDynamicsWorld::getConstraint(int index)
{
        return m_constraints[index];
}
const btTypedConstraint* btDiscreteDynamicsWorld::getConstraint(int index) const
{
        return m_constraints[index];
}