btContinuousDynamicsWorld.cpp

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/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2007 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 "btContinuousDynamicsWorld.h"
#include "LinearMath/btQuickprof.h"

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

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



#include <stdio.h>

btContinuousDynamicsWorld::btContinuousDynamicsWorld(btDispatcher* dispatcher,btBroadphaseInterface* pairCache,btConstraintSolver* constraintSolver,btCollisionConfiguration* collisionConfiguration)
:btDiscreteDynamicsWorld(dispatcher,pairCache,constraintSolver,collisionConfiguration)
{
}

btContinuousDynamicsWorld::~btContinuousDynamicsWorld()
{
}

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


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

    predictUnconstraintMotion(timeStep);

    btDispatcherInfo& dispatchInfo = getDispatchInfo();

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

    performDiscreteCollisionDetection();

    calculateSimulationIslands();

    
    getSolverInfo().m_timeStep = timeStep;
    


    solveConstraints(getSolverInfo());
    
    calculateTimeOfImpacts(timeStep);

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


    integrateTransforms(timeStep * toi);

    updateActions(timeStep);

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

void    btContinuousDynamicsWorld::calculateTimeOfImpacts(btScalar timeStep)
{
        updateTemporalAabbs(timeStep);
        
        btScalar toi = 1.f;
        
    
        btDispatcherInfo& dispatchInfo = getDispatchInfo();
        dispatchInfo.m_timeStep = timeStep;
        dispatchInfo.m_timeOfImpact = 1.f;
        dispatchInfo.m_stepCount = 0;
        dispatchInfo.m_dispatchFunc = btDispatcherInfo::DISPATCH_CONTINUOUS;



        btDispatcher* dispatcher = getDispatcher();
        if (dispatcher)
            dispatcher->dispatchAllCollisionPairs(m_broadphasePairCache->getOverlappingPairCache(),dispatchInfo,m_dispatcher1);

        toi = dispatchInfo.m_timeOfImpact;

        dispatchInfo.m_dispatchFunc = btDispatcherInfo::DISPATCH_DISCRETE;

}

void    btContinuousDynamicsWorld::updateTemporalAabbs(btScalar timeStep)
{

    btVector3 temporalAabbMin,temporalAabbMax;

    for ( int i=0;i<m_collisionObjects.size();i++)
    {
        btCollisionObject* colObj = m_collisionObjects[i];
        
        btRigidBody* body = btRigidBody::upcast(colObj);
        if (body)
        {
            body->getCollisionShape()->getAabb(m_collisionObjects[i]->getWorldTransform(),temporalAabbMin,temporalAabbMax);
            const btVector3& linvel = body->getLinearVelocity();

            //make the AABB temporal
            btScalar temporalAabbMaxx = temporalAabbMax.getX();
            btScalar temporalAabbMaxy = temporalAabbMax.getY();
            btScalar temporalAabbMaxz = temporalAabbMax.getZ();
            btScalar temporalAabbMinx = temporalAabbMin.getX();
            btScalar temporalAabbMiny = temporalAabbMin.getY();
            btScalar temporalAabbMinz = temporalAabbMin.getZ();

            // add linear motion
            btVector3 linMotion = linvel*timeStep;
        
            if (linMotion.x() > 0.f)
                temporalAabbMaxx += linMotion.x(); 
            else
                temporalAabbMinx += linMotion.x();
            if (linMotion.y() > 0.f)
                temporalAabbMaxy += linMotion.y(); 
            else
                temporalAabbMiny += linMotion.y();
            if (linMotion.z() > 0.f)
                temporalAabbMaxz += linMotion.z(); 
            else
                temporalAabbMinz += linMotion.z();

            //add conservative angular motion
            btScalar angularMotion(0);// = angvel.length() * GetAngularMotionDisc() * timeStep;
            btVector3 angularMotion3d(angularMotion,angularMotion,angularMotion);
            temporalAabbMin = btVector3(temporalAabbMinx,temporalAabbMiny,temporalAabbMinz);
            temporalAabbMax = btVector3(temporalAabbMaxx,temporalAabbMaxy,temporalAabbMaxz);

            temporalAabbMin -= angularMotion3d;
            temporalAabbMax += angularMotion3d;

            m_broadphasePairCache->setAabb(body->getBroadphaseHandle(),temporalAabbMin,temporalAabbMax,m_dispatcher1);
        }
    }

    //update aabb (of all moved objects)

    m_broadphasePairCache->calculateOverlappingPairs(m_dispatcher1);
    


}