btCollisionDispatcher.cpp

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/*
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 "btCollisionDispatcher.h"


#include "BulletCollision/BroadphaseCollision/btCollisionAlgorithm.h"

#include "BulletCollision/CollisionShapes/btCollisionShape.h"
#include "BulletCollision/CollisionDispatch/btCollisionObject.h"
#include "BulletCollision/BroadphaseCollision/btOverlappingPairCache.h"
#include "LinearMath/btPoolAllocator.h"
#include "BulletCollision/CollisionDispatch/btCollisionConfiguration.h"

int gNumManifold = 0;

#ifdef BT_DEBUG
#include <stdio.h>
#endif


btCollisionDispatcher::btCollisionDispatcher (btCollisionConfiguration* collisionConfiguration): 
m_dispatcherFlags(btCollisionDispatcher::CD_USE_RELATIVE_CONTACT_BREAKING_THRESHOLD),
    m_collisionConfiguration(collisionConfiguration)
{
    int i;

    setNearCallback(defaultNearCallback);
    
    m_collisionAlgorithmPoolAllocator = collisionConfiguration->getCollisionAlgorithmPool();

    m_persistentManifoldPoolAllocator = collisionConfiguration->getPersistentManifoldPool();

    for (i=0;i<MAX_BROADPHASE_COLLISION_TYPES;i++)
    {
        for (int j=0;j<MAX_BROADPHASE_COLLISION_TYPES;j++)
        {
            m_doubleDispatch[i][j] = m_collisionConfiguration->getCollisionAlgorithmCreateFunc(i,j);
            btAssert(m_doubleDispatch[i][j]);
        }
    }
    
    
}


void btCollisionDispatcher::registerCollisionCreateFunc(int proxyType0, int proxyType1, btCollisionAlgorithmCreateFunc *createFunc)
{
    m_doubleDispatch[proxyType0][proxyType1] = createFunc;
}

btCollisionDispatcher::~btCollisionDispatcher()
{
}

btPersistentManifold*   btCollisionDispatcher::getNewManifold(void* b0,void* b1) 
{ 
    gNumManifold++;
    
    //btAssert(gNumManifold < 65535);
    

    btCollisionObject* body0 = (btCollisionObject*)b0;
    btCollisionObject* body1 = (btCollisionObject*)b1;

    //optional relative contact breaking threshold, turned on by default (use setDispatcherFlags to switch off feature for improved performance)
    
    btScalar contactBreakingThreshold =  (m_dispatcherFlags & btCollisionDispatcher::CD_USE_RELATIVE_CONTACT_BREAKING_THRESHOLD) ? 
        btMin(body0->getCollisionShape()->getContactBreakingThreshold(gContactBreakingThreshold) , body1->getCollisionShape()->getContactBreakingThreshold(gContactBreakingThreshold))
        : gContactBreakingThreshold ;

    btScalar contactProcessingThreshold = btMin(body0->getContactProcessingThreshold(),body1->getContactProcessingThreshold());
        
    void* mem = 0;
    
    if (m_persistentManifoldPoolAllocator->getFreeCount())
    {
        mem = m_persistentManifoldPoolAllocator->allocate(sizeof(btPersistentManifold));
    } else
    {
        mem = btAlignedAlloc(sizeof(btPersistentManifold),16);

    }
    btPersistentManifold* manifold = new(mem) btPersistentManifold (body0,body1,0,contactBreakingThreshold,contactProcessingThreshold);
    manifold->m_index1a = m_manifoldsPtr.size();
    m_manifoldsPtr.push_back(manifold);

    return manifold;
}

void btCollisionDispatcher::clearManifold(btPersistentManifold* manifold)
{
    manifold->clearManifold();
}

    
void btCollisionDispatcher::releaseManifold(btPersistentManifold* manifold)
{
    
    gNumManifold--;

    //printf("releaseManifold: gNumManifold %d\n",gNumManifold);
    clearManifold(manifold);

    int findIndex = manifold->m_index1a;
    btAssert(findIndex < m_manifoldsPtr.size());
    m_manifoldsPtr.swap(findIndex,m_manifoldsPtr.size()-1);
    m_manifoldsPtr[findIndex]->m_index1a = findIndex;
    m_manifoldsPtr.pop_back();

    manifold->~btPersistentManifold();
    if (m_persistentManifoldPoolAllocator->validPtr(manifold))
    {
        m_persistentManifoldPoolAllocator->freeMemory(manifold);
    } else
    {
        btAlignedFree(manifold);
    }
    
}

    

btCollisionAlgorithm* btCollisionDispatcher::findAlgorithm(btCollisionObject* body0,btCollisionObject* body1,btPersistentManifold* sharedManifold)
{
    
    btCollisionAlgorithmConstructionInfo ci;

    ci.m_dispatcher1 = this;
    ci.m_manifold = sharedManifold;
    btCollisionAlgorithm* algo = m_doubleDispatch[body0->getCollisionShape()->getShapeType()][body1->getCollisionShape()->getShapeType()]->CreateCollisionAlgorithm(ci,body0,body1);

    return algo;
}




bool    btCollisionDispatcher::needsResponse(btCollisionObject* body0,btCollisionObject* body1)
{
    //here you can do filtering
    bool hasResponse = 
        (body0->hasContactResponse() && body1->hasContactResponse());
    //no response between two static/kinematic bodies:
    hasResponse = hasResponse &&
        ((!body0->isStaticOrKinematicObject()) ||(! body1->isStaticOrKinematicObject()));
    return hasResponse;
}

bool    btCollisionDispatcher::needsCollision(btCollisionObject* body0,btCollisionObject* body1)
{
    btAssert(body0);
    btAssert(body1);

    bool needsCollision = true;

#ifdef BT_DEBUG
    if (!(m_dispatcherFlags & btCollisionDispatcher::CD_STATIC_STATIC_REPORTED))
    {
        //broadphase filtering already deals with this
        if ((body0->isStaticObject() || body0->isKinematicObject()) &&
            (body1->isStaticObject() || body1->isKinematicObject()))
        {
            m_dispatcherFlags |= btCollisionDispatcher::CD_STATIC_STATIC_REPORTED;
            printf("warning btCollisionDispatcher::needsCollision: static-static collision!\n");
        }
    }
#endif //BT_DEBUG

    if ((!body0->isActive()) && (!body1->isActive()))
        needsCollision = false;
    else if (!body0->checkCollideWith(body1))
        needsCollision = false;
    
    return needsCollision ;

}



class btCollisionPairCallback : public btOverlapCallback
{
    const btDispatcherInfo& m_dispatchInfo;
    btCollisionDispatcher*  m_dispatcher;

public:

    btCollisionPairCallback(const btDispatcherInfo& dispatchInfo,btCollisionDispatcher* dispatcher)
    :m_dispatchInfo(dispatchInfo),
    m_dispatcher(dispatcher)
    {
    }

    /*btCollisionPairCallback& operator=(btCollisionPairCallback& other)
    {
        m_dispatchInfo = other.m_dispatchInfo;
        m_dispatcher = other.m_dispatcher;
        return *this;
    }
    */


    virtual ~btCollisionPairCallback() {}


    virtual bool    processOverlap(btBroadphasePair& pair)
    {
        (*m_dispatcher->getNearCallback())(pair,*m_dispatcher,m_dispatchInfo);

        return false;
    }
};



void    btCollisionDispatcher::dispatchAllCollisionPairs(btOverlappingPairCache* pairCache,const btDispatcherInfo& dispatchInfo,btDispatcher* dispatcher) 
{
    //m_blockedForChanges = true;

    btCollisionPairCallback collisionCallback(dispatchInfo,this);

    pairCache->processAllOverlappingPairs(&collisionCallback,dispatcher);

    //m_blockedForChanges = false;

}




//by default, Bullet will use this near callback
void btCollisionDispatcher::defaultNearCallback(btBroadphasePair& collisionPair, btCollisionDispatcher& dispatcher, const btDispatcherInfo& dispatchInfo)
{
        btCollisionObject* colObj0 = (btCollisionObject*)collisionPair.m_pProxy0->m_clientObject;
        btCollisionObject* colObj1 = (btCollisionObject*)collisionPair.m_pProxy1->m_clientObject;

        if (dispatcher.needsCollision(colObj0,colObj1))
        {
            //dispatcher will keep algorithms persistent in the collision pair
            if (!collisionPair.m_algorithm)
            {
                collisionPair.m_algorithm = dispatcher.findAlgorithm(colObj0,colObj1);
            }

            if (collisionPair.m_algorithm)
            {
                btManifoldResult contactPointResult(colObj0,colObj1);
                
                if (dispatchInfo.m_dispatchFunc ==      btDispatcherInfo::DISPATCH_DISCRETE)
                {
                    //discrete collision detection query
                    collisionPair.m_algorithm->processCollision(colObj0,colObj1,dispatchInfo,&contactPointResult);
                } else
                {
                    //continuous collision detection query, time of impact (toi)
                    btScalar toi = collisionPair.m_algorithm->calculateTimeOfImpact(colObj0,colObj1,dispatchInfo,&contactPointResult);
                    if (dispatchInfo.m_timeOfImpact > toi)
                        dispatchInfo.m_timeOfImpact = toi;

                }
            }
        }

}


void* btCollisionDispatcher::allocateCollisionAlgorithm(int size)
{
    if (m_collisionAlgorithmPoolAllocator->getFreeCount())
    {
        return m_collisionAlgorithmPoolAllocator->allocate(size);
    }
    
    //warn user for overflow?
    return  btAlignedAlloc(static_cast<size_t>(size), 16);
}

void btCollisionDispatcher::freeCollisionAlgorithm(void* ptr)
{
    if (m_collisionAlgorithmPoolAllocator->validPtr(ptr))
    {
        m_collisionAlgorithmPoolAllocator->freeMemory(ptr);
    } else
    {
        btAlignedFree(ptr);
    }
}