btConvexConvexAlgorithm.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.
*/

//#define BT_DISABLE_CAPSULE_CAPSULE_COLLIDER 1
//#define ZERO_MARGIN
 
#include "btConvexConvexAlgorithm.h"
 
//#include <stdio.h>
#include "BulletCollision/NarrowPhaseCollision/btDiscreteCollisionDetectorInterface.h"
#include "BulletCollision/BroadphaseCollision/btBroadphaseInterface.h"
#include "BulletCollision/CollisionDispatch/btCollisionObject.h"
#include "BulletCollision/CollisionShapes/btConvexShape.h"
#include "BulletCollision/CollisionShapes/btCapsuleShape.h"
#include "BulletCollision/CollisionShapes/btTriangleShape.h"
#include "BulletCollision/CollisionShapes/btConvexPolyhedron.h"
 
#include "BulletCollision/NarrowPhaseCollision/btGjkPairDetector.h"
#include "BulletCollision/BroadphaseCollision/btBroadphaseProxy.h"
#include "BulletCollision/CollisionDispatch/btCollisionDispatcher.h"
#include "BulletCollision/CollisionShapes/btBoxShape.h"
#include "BulletCollision/CollisionDispatch/btManifoldResult.h"
 
#include "BulletCollision/NarrowPhaseCollision/btConvexPenetrationDepthSolver.h"
#include "BulletCollision/NarrowPhaseCollision/btContinuousConvexCollision.h"
#include "BulletCollision/NarrowPhaseCollision/btSubSimplexConvexCast.h"
#include "BulletCollision/NarrowPhaseCollision/btGjkConvexCast.h"
 
#include "BulletCollision/NarrowPhaseCollision/btVoronoiSimplexSolver.h"
#include "BulletCollision/CollisionShapes/btSphereShape.h"
 
#include "BulletCollision/NarrowPhaseCollision/btMinkowskiPenetrationDepthSolver.h"
 
#include "BulletCollision/NarrowPhaseCollision/btGjkEpa2.h"
#include "BulletCollision/NarrowPhaseCollision/btGjkEpaPenetrationDepthSolver.h"
#include "BulletCollision/NarrowPhaseCollision/btPolyhedralContactClipping.h"
#include "BulletCollision/CollisionDispatch/btCollisionObjectWrapper.h"

 
static SIMD_FORCE_INLINE void segmentsClosestPoints(
    btVector3& ptsVector,
    btVector3& offsetA,
    btVector3& offsetB,
    btScalar& tA, btScalar& tB,
    const btVector3& translation,
    const btVector3& dirA, btScalar hlenA,
    const btVector3& dirB, btScalar hlenB)
{
    // compute the parameters of the closest points on each line segment
 
    btScalar dirA_dot_dirB = btDot(dirA, dirB);
    btScalar dirA_dot_trans = btDot(dirA, translation);
    btScalar dirB_dot_trans = btDot(dirB, translation);
 
    btScalar denom = 1.0f - dirA_dot_dirB * dirA_dot_dirB;
 
    if (denom == 0.0f)
    {
        tA = 0.0f;
    }
    else
    {
        tA = (dirA_dot_trans - dirB_dot_trans * dirA_dot_dirB) / denom;
        if (tA < -hlenA)
            tA = -hlenA;
        else if (tA > hlenA)
            tA = hlenA;
    }
 
    tB = tA * dirA_dot_dirB - dirB_dot_trans;
 
    if (tB < -hlenB)
    {
        tB = -hlenB;
        tA = tB * dirA_dot_dirB + dirA_dot_trans;
 
        if (tA < -hlenA)
            tA = -hlenA;
        else if (tA > hlenA)
            tA = hlenA;
    }
    else if (tB > hlenB)
    {
        tB = hlenB;
        tA = tB * dirA_dot_dirB + dirA_dot_trans;
 
        if (tA < -hlenA)
            tA = -hlenA;
        else if (tA > hlenA)
            tA = hlenA;
    }
 
    // compute the closest points relative to segment centers.
 
    offsetA = dirA * tA;
    offsetB = dirB * tB;
 
    ptsVector = translation - offsetA + offsetB;
}
 
static SIMD_FORCE_INLINE btScalar capsuleCapsuleDistance(
    btVector3& normalOnB,
    btVector3& pointOnB,
    btScalar capsuleLengthA,
    btScalar capsuleRadiusA,
    btScalar capsuleLengthB,
    btScalar capsuleRadiusB,
    int capsuleAxisA,
    int capsuleAxisB,
    const btTransform& transformA,
    const btTransform& transformB,
    btScalar distanceThreshold)
{
    btVector3 directionA = transformA.getBasis().getColumn(capsuleAxisA);
    btVector3 translationA = transformA.getOrigin();
    btVector3 directionB = transformB.getBasis().getColumn(capsuleAxisB);
    btVector3 translationB = transformB.getOrigin();
 
    // translation between centers
 
    btVector3 translation = translationB - translationA;
 
    // compute the closest points of the capsule line segments
 
    btVector3 ptsVector;  // the vector between the closest points
 
    btVector3 offsetA, offsetB;  // offsets from segment centers to their closest points
    btScalar tA, tB;             // parameters on line segment
 
    segmentsClosestPoints(ptsVector, offsetA, offsetB, tA, tB, translation,
                          directionA, capsuleLengthA, directionB, capsuleLengthB);
 
    btScalar distance = ptsVector.length() - capsuleRadiusA - capsuleRadiusB;
 
    if (distance > distanceThreshold)
        return distance;
 
    btScalar lenSqr = ptsVector.length2();
    if (lenSqr <= (SIMD_EPSILON * SIMD_EPSILON))
    {
        //degenerate case where 2 capsules are likely at the same location: take a vector tangential to 'directionA'
        btVector3 q;
        btPlaneSpace1(directionA, normalOnB, q);
    }
    else
    {
        // compute the contact normal
        normalOnB = ptsVector * -btRecipSqrt(lenSqr);
    }
    pointOnB = transformB.getOrigin() + offsetB + normalOnB * capsuleRadiusB;
 
    return distance;
}

 
btConvexConvexAlgorithm::CreateFunc::CreateFunc(btConvexPenetrationDepthSolver* pdSolver)
{
    m_numPerturbationIterations = 0;
    m_minimumPointsPerturbationThreshold = 3;
    m_pdSolver = pdSolver;
}
 
btConvexConvexAlgorithm::CreateFunc::~CreateFunc()
{
}
 
btConvexConvexAlgorithm::btConvexConvexAlgorithm(btPersistentManifold* mf, const btCollisionAlgorithmConstructionInfo& ci, const btCollisionObjectWrapper* body0Wrap, const btCollisionObjectWrapper* body1Wrap, btConvexPenetrationDepthSolver* pdSolver, int numPerturbationIterations, int minimumPointsPerturbationThreshold)
    : btActivatingCollisionAlgorithm(ci, body0Wrap, body1Wrap),
      m_pdSolver(pdSolver),
      m_ownManifold(false),
      m_manifoldPtr(mf),
      m_lowLevelOfDetail(false),
#ifdef USE_SEPDISTANCE_UTIL2
      m_sepDistance((static_cast<btConvexShape*>(body0->getCollisionShape()))->getAngularMotionDisc(),
                    (static_cast<btConvexShape*>(body1->getCollisionShape()))->getAngularMotionDisc()),
#endif
      m_numPerturbationIterations(numPerturbationIterations),
      m_minimumPointsPerturbationThreshold(minimumPointsPerturbationThreshold)
{
    (void)body0Wrap;
    (void)body1Wrap;
}
 
btConvexConvexAlgorithm::~btConvexConvexAlgorithm()
{
    if (m_ownManifold)
    {
        if (m_manifoldPtr)
            m_dispatcher->releaseManifold(m_manifoldPtr);
    }
}
 
void btConvexConvexAlgorithm ::setLowLevelOfDetail(bool useLowLevel)
{
    m_lowLevelOfDetail = useLowLevel;
}
 
struct btPerturbedContactResult : public btManifoldResult
{
    btManifoldResult* m_originalManifoldResult;
    btTransform m_transformA;
    btTransform m_transformB;
    btTransform m_unPerturbedTransform;
    bool m_perturbA;
    btIDebugDraw* m_debugDrawer;
 
    btPerturbedContactResult(btManifoldResult* originalResult, const btTransform& transformA, const btTransform& transformB, const btTransform& unPerturbedTransform, bool perturbA, btIDebugDraw* debugDrawer)
        : m_originalManifoldResult(originalResult),
          m_transformA(transformA),
          m_transformB(transformB),
          m_unPerturbedTransform(unPerturbedTransform),
          m_perturbA(perturbA),
          m_debugDrawer(debugDrawer)
    {
    }
    virtual ~btPerturbedContactResult()
    {
    }
 
    virtual void addContactPoint(const btVector3& normalOnBInWorld, const btVector3& pointInWorld, btScalar orgDepth)
    {
        btVector3 endPt, startPt;
        btScalar newDepth;
        btVector3 newNormal;
 
        if (m_perturbA)
        {
            btVector3 endPtOrg = pointInWorld + normalOnBInWorld * orgDepth;
            endPt = (m_unPerturbedTransform * m_transformA.inverse())(endPtOrg);
            newDepth = (endPt - pointInWorld).dot(normalOnBInWorld);
            startPt = endPt - normalOnBInWorld * newDepth;
        }
        else
        {
            endPt = pointInWorld + normalOnBInWorld * orgDepth;
            startPt = (m_unPerturbedTransform * m_transformB.inverse())(pointInWorld);
            newDepth = (endPt - startPt).dot(normalOnBInWorld);
        }
 
//#define DEBUG_CONTACTS 1
#ifdef DEBUG_CONTACTS
        m_debugDrawer->drawLine(startPt, endPt, btVector3(1, 0, 0));
        m_debugDrawer->drawSphere(startPt, 0.05, btVector3(0, 1, 0));
        m_debugDrawer->drawSphere(endPt, 0.05, btVector3(0, 0, 1));
#endif  //DEBUG_CONTACTS
 
        m_originalManifoldResult->addContactPoint(normalOnBInWorld, startPt, newDepth);
    }
};
 
extern btScalar gContactBreakingThreshold;
 
//
// Convex-Convex collision algorithm
//
void btConvexConvexAlgorithm ::processCollision(const btCollisionObjectWrapper* body0Wrap, const btCollisionObjectWrapper* body1Wrap, const btDispatcherInfo& dispatchInfo, btManifoldResult* resultOut)
{
    if (!m_manifoldPtr)
    {
        //swapped?
        m_manifoldPtr = m_dispatcher->getNewManifold(body0Wrap->getCollisionObject(), body1Wrap->getCollisionObject());
        m_ownManifold = true;
    }
    resultOut->setPersistentManifold(m_manifoldPtr);
 
    //comment-out next line to test multi-contact generation
    //resultOut->getPersistentManifold()->clearManifold();
 
    const btConvexShape* min0 = static_cast<const btConvexShape*>(body0Wrap->getCollisionShape());
    const btConvexShape* min1 = static_cast<const btConvexShape*>(body1Wrap->getCollisionShape());
 
    btVector3 normalOnB;
    btVector3 pointOnBWorld;
#ifndef BT_DISABLE_CAPSULE_CAPSULE_COLLIDER
    if ((min0->getShapeType() == CAPSULE_SHAPE_PROXYTYPE) && (min1->getShapeType() == CAPSULE_SHAPE_PROXYTYPE))
    {
        //m_manifoldPtr->clearManifold();
 
        btCapsuleShape* capsuleA = (btCapsuleShape*)min0;
        btCapsuleShape* capsuleB = (btCapsuleShape*)min1;
 
        btScalar threshold = m_manifoldPtr->getContactBreakingThreshold()+ resultOut->m_closestPointDistanceThreshold;
 
        btScalar dist = capsuleCapsuleDistance(normalOnB, pointOnBWorld, capsuleA->getHalfHeight(), capsuleA->getRadius(),
                                               capsuleB->getHalfHeight(), capsuleB->getRadius(), capsuleA->getUpAxis(), capsuleB->getUpAxis(),
                                               body0Wrap->getWorldTransform(), body1Wrap->getWorldTransform(), threshold);
 
        if (dist < threshold)
        {
            btAssert(normalOnB.length2() >= (SIMD_EPSILON * SIMD_EPSILON));
            resultOut->addContactPoint(normalOnB, pointOnBWorld, dist);
        }
        resultOut->refreshContactPoints();
        return;
    }
 
    if ((min0->getShapeType() == CAPSULE_SHAPE_PROXYTYPE) && (min1->getShapeType() == SPHERE_SHAPE_PROXYTYPE))
    {
        //m_manifoldPtr->clearManifold();
 
        btCapsuleShape* capsuleA = (btCapsuleShape*)min0;
        btSphereShape* capsuleB = (btSphereShape*)min1;
 
        btScalar threshold = m_manifoldPtr->getContactBreakingThreshold()+ resultOut->m_closestPointDistanceThreshold;
 
        btScalar dist = capsuleCapsuleDistance(normalOnB, pointOnBWorld, capsuleA->getHalfHeight(), capsuleA->getRadius(),
                                               0., capsuleB->getRadius(), capsuleA->getUpAxis(), 1,
                                               body0Wrap->getWorldTransform(), body1Wrap->getWorldTransform(), threshold);
 
        if (dist < threshold)
        {
            btAssert(normalOnB.length2() >= (SIMD_EPSILON * SIMD_EPSILON));
            resultOut->addContactPoint(normalOnB, pointOnBWorld, dist);
        }
        resultOut->refreshContactPoints();
        return;
    }
 
    if ((min0->getShapeType() == SPHERE_SHAPE_PROXYTYPE) && (min1->getShapeType() == CAPSULE_SHAPE_PROXYTYPE))
    {
        //m_manifoldPtr->clearManifold();
 
        btSphereShape* capsuleA = (btSphereShape*)min0;
        btCapsuleShape* capsuleB = (btCapsuleShape*)min1;
 
        btScalar threshold = m_manifoldPtr->getContactBreakingThreshold()+ resultOut->m_closestPointDistanceThreshold;
 
        btScalar dist = capsuleCapsuleDistance(normalOnB, pointOnBWorld, 0., capsuleA->getRadius(),
                                               capsuleB->getHalfHeight(), capsuleB->getRadius(), 1, capsuleB->getUpAxis(),
                                               body0Wrap->getWorldTransform(), body1Wrap->getWorldTransform(), threshold);
 
        if (dist < threshold)
        {
            btAssert(normalOnB.length2() >= (SIMD_EPSILON * SIMD_EPSILON));
            resultOut->addContactPoint(normalOnB, pointOnBWorld, dist);
        }
        resultOut->refreshContactPoints();
        return;
    }
#endif  //BT_DISABLE_CAPSULE_CAPSULE_COLLIDER
 
#ifdef USE_SEPDISTANCE_UTIL2
    if (dispatchInfo.m_useConvexConservativeDistanceUtil)
    {
        m_sepDistance.updateSeparatingDistance(body0->getWorldTransform(), body1->getWorldTransform());
    }
 
    if (!dispatchInfo.m_useConvexConservativeDistanceUtil || m_sepDistance.getConservativeSeparatingDistance() <= 0.f)
#endif  //USE_SEPDISTANCE_UTIL2
 
    {
        btGjkPairDetector::ClosestPointInput input;
        btVoronoiSimplexSolver simplexSolver;
        btGjkPairDetector gjkPairDetector(min0, min1, &simplexSolver, m_pdSolver);
        //TODO: if (dispatchInfo.m_useContinuous)
        gjkPairDetector.setMinkowskiA(min0);
        gjkPairDetector.setMinkowskiB(min1);
 
#ifdef USE_SEPDISTANCE_UTIL2
        if (dispatchInfo.m_useConvexConservativeDistanceUtil)
        {
            input.m_maximumDistanceSquared = BT_LARGE_FLOAT;
        }
        else
#endif  //USE_SEPDISTANCE_UTIL2
        {
            //if (dispatchInfo.m_convexMaxDistanceUseCPT)
            //{
            //  input.m_maximumDistanceSquared = min0->getMargin() + min1->getMargin() + m_manifoldPtr->getContactProcessingThreshold();
            //} else
            //{
            input.m_maximumDistanceSquared = min0->getMargin() + min1->getMargin() + m_manifoldPtr->getContactBreakingThreshold() + resultOut->m_closestPointDistanceThreshold;
            //      }
 
            input.m_maximumDistanceSquared *= input.m_maximumDistanceSquared;
        }
 
        input.m_transformA = body0Wrap->getWorldTransform();
        input.m_transformB = body1Wrap->getWorldTransform();
 
#ifdef USE_SEPDISTANCE_UTIL2
        btScalar sepDist = 0.f;
        if (dispatchInfo.m_useConvexConservativeDistanceUtil)
        {
            sepDist = gjkPairDetector.getCachedSeparatingDistance();
            if (sepDist > SIMD_EPSILON)
            {
                sepDist += dispatchInfo.m_convexConservativeDistanceThreshold;
                //now perturbe directions to get multiple contact points
            }
        }
#endif  //USE_SEPDISTANCE_UTIL2
 
        if (min0->isPolyhedral() && min1->isPolyhedral())
        {
            struct btDummyResult : public btDiscreteCollisionDetectorInterface::Result
            {
                btVector3 m_normalOnBInWorld;
                btVector3 m_pointInWorld;
                btScalar m_depth;
                bool m_hasContact;
 
                btDummyResult()
                    : m_hasContact(false)
                {
                }
 
                virtual void setShapeIdentifiersA(int partId0, int index0) {}
                virtual void setShapeIdentifiersB(int partId1, int index1) {}
                virtual void addContactPoint(const btVector3& normalOnBInWorld, const btVector3& pointInWorld, btScalar depth)
                {
                    m_hasContact = true;
                    m_normalOnBInWorld = normalOnBInWorld;
                    m_pointInWorld = pointInWorld;
                    m_depth = depth;
                }
            };
 
            struct btWithoutMarginResult : public btDiscreteCollisionDetectorInterface::Result
            {
                btDiscreteCollisionDetectorInterface::Result* m_originalResult;
                btVector3 m_reportedNormalOnWorld;
                btScalar m_marginOnA;
                btScalar m_marginOnB;
                btScalar m_reportedDistance;
 
                bool m_foundResult;
                btWithoutMarginResult(btDiscreteCollisionDetectorInterface::Result* result, btScalar marginOnA, btScalar marginOnB)
                    : m_originalResult(result),
                      m_marginOnA(marginOnA),
                      m_marginOnB(marginOnB),
                      m_foundResult(false)
                {
                }
 
                virtual void setShapeIdentifiersA(int partId0, int index0) {}
                virtual void setShapeIdentifiersB(int partId1, int index1) {}
                virtual void addContactPoint(const btVector3& normalOnBInWorld, const btVector3& pointInWorldOrg, btScalar depthOrg)
                {
                    m_reportedDistance = depthOrg;
                    m_reportedNormalOnWorld = normalOnBInWorld;
 
                    btVector3 adjustedPointB = pointInWorldOrg - normalOnBInWorld * m_marginOnB;
                    m_reportedDistance = depthOrg + (m_marginOnA + m_marginOnB);
                    if (m_reportedDistance < 0.f)
                    {
                        m_foundResult = true;
                    }
                    m_originalResult->addContactPoint(normalOnBInWorld, adjustedPointB, m_reportedDistance);
                }
            };
 
            btDummyResult dummy;

 
            btScalar min0Margin = min0->getShapeType() == BOX_SHAPE_PROXYTYPE ? 0.f : min0->getMargin();
            btScalar min1Margin = min1->getShapeType() == BOX_SHAPE_PROXYTYPE ? 0.f : min1->getMargin();
 
            btWithoutMarginResult withoutMargin(resultOut, min0Margin, min1Margin);
 
            btPolyhedralConvexShape* polyhedronA = (btPolyhedralConvexShape*)min0;
            btPolyhedralConvexShape* polyhedronB = (btPolyhedralConvexShape*)min1;
            if (polyhedronA->getConvexPolyhedron() && polyhedronB->getConvexPolyhedron())
            {
                btScalar threshold = m_manifoldPtr->getContactBreakingThreshold()+ resultOut->m_closestPointDistanceThreshold;
 
                btScalar minDist = -1e30f;
                btVector3 sepNormalWorldSpace;
                bool foundSepAxis = true;
 
                if (dispatchInfo.m_enableSatConvex)
                {
                    foundSepAxis = btPolyhedralContactClipping::findSeparatingAxis(
                        *polyhedronA->getConvexPolyhedron(), *polyhedronB->getConvexPolyhedron(),
                        body0Wrap->getWorldTransform(),
                        body1Wrap->getWorldTransform(),
                        sepNormalWorldSpace, *resultOut);
                }
                else
                {
#ifdef ZERO_MARGIN
                    gjkPairDetector.setIgnoreMargin(true);
                    gjkPairDetector.getClosestPoints(input, *resultOut, dispatchInfo.m_debugDraw);
#else
 
                    gjkPairDetector.getClosestPoints(input, withoutMargin, dispatchInfo.m_debugDraw);
                    //gjkPairDetector.getClosestPoints(input,dummy,dispatchInfo.m_debugDraw);
#endif  //ZERO_MARGIN
                    //btScalar l2 = gjkPairDetector.getCachedSeparatingAxis().length2();
                    //if (l2>SIMD_EPSILON)
                    {
                        sepNormalWorldSpace = withoutMargin.m_reportedNormalOnWorld;  //gjkPairDetector.getCachedSeparatingAxis()*(1.f/l2);
                        //minDist = -1e30f;//gjkPairDetector.getCachedSeparatingDistance();
                        minDist = withoutMargin.m_reportedDistance;  //gjkPairDetector.getCachedSeparatingDistance()+min0->getMargin()+min1->getMargin();
 
#ifdef ZERO_MARGIN
                        foundSepAxis = true;  //gjkPairDetector.getCachedSeparatingDistance()<0.f;
#else
                        foundSepAxis = withoutMargin.m_foundResult && minDist < 0;  //-(min0->getMargin()+min1->getMargin());
#endif
                    }
                }
                if (foundSepAxis)
                {
                    //              printf("sepNormalWorldSpace=%f,%f,%f\n",sepNormalWorldSpace.getX(),sepNormalWorldSpace.getY(),sepNormalWorldSpace.getZ());
 
                    worldVertsB1.resize(0);
                    btPolyhedralContactClipping::clipHullAgainstHull(sepNormalWorldSpace, *polyhedronA->getConvexPolyhedron(), *polyhedronB->getConvexPolyhedron(),
                                                                     body0Wrap->getWorldTransform(),
                                                                     body1Wrap->getWorldTransform(), minDist - threshold, threshold, worldVertsB1, worldVertsB2,
                                                                     *resultOut);
                }
                if (m_ownManifold)
                {
                    resultOut->refreshContactPoints();
                }
                return;
            }
            else
            {
                //we can also deal with convex versus triangle (without connectivity data)
                if (dispatchInfo.m_enableSatConvex && polyhedronA->getConvexPolyhedron() && polyhedronB->getShapeType() == TRIANGLE_SHAPE_PROXYTYPE)
                {
                    btVertexArray worldSpaceVertices;
                    btTriangleShape* tri = (btTriangleShape*)polyhedronB;
                    worldSpaceVertices.push_back(body1Wrap->getWorldTransform() * tri->m_vertices1[0]);
                    worldSpaceVertices.push_back(body1Wrap->getWorldTransform() * tri->m_vertices1[1]);
                    worldSpaceVertices.push_back(body1Wrap->getWorldTransform() * tri->m_vertices1[2]);
 
                    //tri->initializePolyhedralFeatures();
 
                    btScalar threshold = m_manifoldPtr->getContactBreakingThreshold()+ resultOut->m_closestPointDistanceThreshold;
 
                    btVector3 sepNormalWorldSpace;
                    btScalar minDist = -1e30f;
                    btScalar maxDist = threshold;
 
                    bool foundSepAxis = false;
                    bool useSatSepNormal = true;
 
                    if (useSatSepNormal)
                    {
#if 0
                    if (0)
                    {
                        //initializePolyhedralFeatures performs a convex hull computation, not needed for a single triangle
                        polyhedronB->initializePolyhedralFeatures();
                    } else
#endif
                        {
                            btVector3 uniqueEdges[3] = {tri->m_vertices1[1] - tri->m_vertices1[0],
                                                        tri->m_vertices1[2] - tri->m_vertices1[1],
                                                        tri->m_vertices1[0] - tri->m_vertices1[2]};
 
                            uniqueEdges[0].normalize();
                            uniqueEdges[1].normalize();
                            uniqueEdges[2].normalize();
 
                            btConvexPolyhedron polyhedron;
                            polyhedron.m_vertices.push_back(tri->m_vertices1[2]);
                            polyhedron.m_vertices.push_back(tri->m_vertices1[0]);
                            polyhedron.m_vertices.push_back(tri->m_vertices1[1]);
 
                            {
                                btFace combinedFaceA;
                                combinedFaceA.m_indices.push_back(0);
                                combinedFaceA.m_indices.push_back(1);
                                combinedFaceA.m_indices.push_back(2);
                                btVector3 faceNormal = uniqueEdges[0].cross(uniqueEdges[1]);
                                faceNormal.normalize();
                                btScalar planeEq = 1e30f;
                                for (int v = 0; v < combinedFaceA.m_indices.size(); v++)
                                {
                                    btScalar eq = tri->m_vertices1[combinedFaceA.m_indices[v]].dot(faceNormal);
                                    if (planeEq > eq)
                                    {
                                        planeEq = eq;
                                    }
                                }
                                combinedFaceA.m_plane[0] = faceNormal[0];
                                combinedFaceA.m_plane[1] = faceNormal[1];
                                combinedFaceA.m_plane[2] = faceNormal[2];
                                combinedFaceA.m_plane[3] = -planeEq;
                                polyhedron.m_faces.push_back(combinedFaceA);
                            }
                            {
                                btFace combinedFaceB;
                                combinedFaceB.m_indices.push_back(0);
                                combinedFaceB.m_indices.push_back(2);
                                combinedFaceB.m_indices.push_back(1);
                                btVector3 faceNormal = -uniqueEdges[0].cross(uniqueEdges[1]);
                                faceNormal.normalize();
                                btScalar planeEq = 1e30f;
                                for (int v = 0; v < combinedFaceB.m_indices.size(); v++)
                                {
                                    btScalar eq = tri->m_vertices1[combinedFaceB.m_indices[v]].dot(faceNormal);
                                    if (planeEq > eq)
                                    {
                                        planeEq = eq;
                                    }
                                }
 
                                combinedFaceB.m_plane[0] = faceNormal[0];
                                combinedFaceB.m_plane[1] = faceNormal[1];
                                combinedFaceB.m_plane[2] = faceNormal[2];
                                combinedFaceB.m_plane[3] = -planeEq;
                                polyhedron.m_faces.push_back(combinedFaceB);
                            }
 
                            polyhedron.m_uniqueEdges.push_back(uniqueEdges[0]);
                            polyhedron.m_uniqueEdges.push_back(uniqueEdges[1]);
                            polyhedron.m_uniqueEdges.push_back(uniqueEdges[2]);
                            polyhedron.initialize2();
 
                            polyhedronB->setPolyhedralFeatures(polyhedron);
                        }
 
                        foundSepAxis = btPolyhedralContactClipping::findSeparatingAxis(
                            *polyhedronA->getConvexPolyhedron(), *polyhedronB->getConvexPolyhedron(),
                            body0Wrap->getWorldTransform(),
                            body1Wrap->getWorldTransform(),
                            sepNormalWorldSpace, *resultOut);
                        //   printf("sepNormalWorldSpace=%f,%f,%f\n",sepNormalWorldSpace.getX(),sepNormalWorldSpace.getY(),sepNormalWorldSpace.getZ());
                    }
                    else
                    {
#ifdef ZERO_MARGIN
                        gjkPairDetector.setIgnoreMargin(true);
                        gjkPairDetector.getClosestPoints(input, *resultOut, dispatchInfo.m_debugDraw);
#else
                        gjkPairDetector.getClosestPoints(input, dummy, dispatchInfo.m_debugDraw);
#endif  //ZERO_MARGIN
 
                        if (dummy.m_hasContact && dummy.m_depth < 0)
                        {
                            if (foundSepAxis)
                            {
                                if (dummy.m_normalOnBInWorld.dot(sepNormalWorldSpace) < 0.99)
                                {
                                    printf("?\n");
                                }
                            }
                            else
                            {
                                printf("!\n");
                            }
                            sepNormalWorldSpace.setValue(0, 0, 1);  // = dummy.m_normalOnBInWorld;
                            //minDist = dummy.m_depth;
                            foundSepAxis = true;
                        }
#if 0
                    btScalar l2 = gjkPairDetector.getCachedSeparatingAxis().length2();
                    if (l2>SIMD_EPSILON)
                    {
                        sepNormalWorldSpace = gjkPairDetector.getCachedSeparatingAxis()*(1.f/l2);
                        //minDist = gjkPairDetector.getCachedSeparatingDistance();
                        //maxDist = threshold;
                        minDist = gjkPairDetector.getCachedSeparatingDistance()-min0->getMargin()-min1->getMargin();
                        foundSepAxis = true;
                    }
#endif
                    }
 
                    if (foundSepAxis)
                    {
                        worldVertsB2.resize(0);
                        btPolyhedralContactClipping::clipFaceAgainstHull(sepNormalWorldSpace, *polyhedronA->getConvexPolyhedron(),
                                                                         body0Wrap->getWorldTransform(), worldSpaceVertices, worldVertsB2, minDist - threshold, maxDist, *resultOut);
                    }
 
                    if (m_ownManifold)
                    {
                        resultOut->refreshContactPoints();
                    }
 
                    return;
                }
            }
        }
 
        gjkPairDetector.getClosestPoints(input, *resultOut, dispatchInfo.m_debugDraw);
 
        //now perform 'm_numPerturbationIterations' collision queries with the perturbated collision objects
 
        //perform perturbation when more then 'm_minimumPointsPerturbationThreshold' points
        if (m_numPerturbationIterations && resultOut->getPersistentManifold()->getNumContacts() < m_minimumPointsPerturbationThreshold)
        {
            int i;
            btVector3 v0, v1;
            btVector3 sepNormalWorldSpace;
            btScalar l2 = gjkPairDetector.getCachedSeparatingAxis().length2();
 
            if (l2 > SIMD_EPSILON)
            {
                sepNormalWorldSpace = gjkPairDetector.getCachedSeparatingAxis() * (1.f / l2);
 
                btPlaneSpace1(sepNormalWorldSpace, v0, v1);
 
                bool perturbeA = true;
                const btScalar angleLimit = 0.125f * SIMD_PI;
                btScalar perturbeAngle;
                btScalar radiusA = min0->getAngularMotionDisc();
                btScalar radiusB = min1->getAngularMotionDisc();
                if (radiusA < radiusB)
                {
                    perturbeAngle = gContactBreakingThreshold / radiusA;
                    perturbeA = true;
                }
                else
                {
                    perturbeAngle = gContactBreakingThreshold / radiusB;
                    perturbeA = false;
                }
                if (perturbeAngle > angleLimit)
                    perturbeAngle = angleLimit;
 
                btTransform unPerturbedTransform;
                if (perturbeA)
                {
                    unPerturbedTransform = input.m_transformA;
                }
                else
                {
                    unPerturbedTransform = input.m_transformB;
                }
 
                for (i = 0; i < m_numPerturbationIterations; i++)
                {
                    if (v0.length2() > SIMD_EPSILON)
                    {
                        btQuaternion perturbeRot(v0, perturbeAngle);
                        btScalar iterationAngle = i * (SIMD_2_PI / btScalar(m_numPerturbationIterations));
                        btQuaternion rotq(sepNormalWorldSpace, iterationAngle);
 
                        if (perturbeA)
                        {
                            input.m_transformA.setBasis(btMatrix3x3(rotq.inverse() * perturbeRot * rotq) * body0Wrap->getWorldTransform().getBasis());
                            input.m_transformB = body1Wrap->getWorldTransform();
#ifdef DEBUG_CONTACTS
                            dispatchInfo.m_debugDraw->drawTransform(input.m_transformA, 10.0);
#endif  //DEBUG_CONTACTS
                        }
                        else
                        {
                            input.m_transformA = body0Wrap->getWorldTransform();
                            input.m_transformB.setBasis(btMatrix3x3(rotq.inverse() * perturbeRot * rotq) * body1Wrap->getWorldTransform().getBasis());
#ifdef DEBUG_CONTACTS
                            dispatchInfo.m_debugDraw->drawTransform(input.m_transformB, 10.0);
#endif
                        }
 
                        btPerturbedContactResult perturbedResultOut(resultOut, input.m_transformA, input.m_transformB, unPerturbedTransform, perturbeA, dispatchInfo.m_debugDraw);
                        gjkPairDetector.getClosestPoints(input, perturbedResultOut, dispatchInfo.m_debugDraw);
                    }
                }
            }
        }
 
#ifdef USE_SEPDISTANCE_UTIL2
        if (dispatchInfo.m_useConvexConservativeDistanceUtil && (sepDist > SIMD_EPSILON))
        {
            m_sepDistance.initSeparatingDistance(gjkPairDetector.getCachedSeparatingAxis(), sepDist, body0->getWorldTransform(), body1->getWorldTransform());
        }
#endif  //USE_SEPDISTANCE_UTIL2
    }
 
    if (m_ownManifold)
    {
        resultOut->refreshContactPoints();
    }
}
 
bool disableCcd = false;
btScalar btConvexConvexAlgorithm::calculateTimeOfImpact(btCollisionObject* col0, btCollisionObject* col1, const btDispatcherInfo& dispatchInfo, btManifoldResult* resultOut)
{
    (void)resultOut;
    (void)dispatchInfo;

    btScalar resultFraction = btScalar(1.);
 
    btScalar squareMot0 = (col0->getInterpolationWorldTransform().getOrigin() - col0->getWorldTransform().getOrigin()).length2();
    btScalar squareMot1 = (col1->getInterpolationWorldTransform().getOrigin() - col1->getWorldTransform().getOrigin()).length2();
 
    if (squareMot0 < col0->getCcdSquareMotionThreshold() &&
        squareMot1 < col1->getCcdSquareMotionThreshold())
        return resultFraction;
 
    if (disableCcd)
        return btScalar(1.);
 
    //An adhoc way of testing the Continuous Collision Detection algorithms
    //One object is approximated as a sphere, to simplify things
    //Starting in penetration should report no time of impact
    //For proper CCD, better accuracy and handling of 'allowed' penetration should be added
    //also the mainloop of the physics should have a kind of toi queue (something like Brian Mirtich's application of Timewarp for Rigidbodies)

    {
        btConvexShape* convex0 = static_cast<btConvexShape*>(col0->getCollisionShape());
 
        btSphereShape sphere1(col1->getCcdSweptSphereRadius());  //todo: allow non-zero sphere sizes, for better approximation
        btConvexCast::CastResult result;
        btVoronoiSimplexSolver voronoiSimplex;
        //SubsimplexConvexCast ccd0(&sphere,min0,&voronoiSimplex);
        btGjkConvexCast ccd1(convex0, &sphere1, &voronoiSimplex);
        //ContinuousConvexCollision ccd(min0,min1,&voronoiSimplex,0);
        if (ccd1.calcTimeOfImpact(col0->getWorldTransform(), col0->getInterpolationWorldTransform(),
                                  col1->getWorldTransform(), col1->getInterpolationWorldTransform(), result))
        {
            //store result.m_fraction in both bodies
 
            if (col0->getHitFraction() > result.m_fraction)
                col0->setHitFraction(result.m_fraction);
 
            if (col1->getHitFraction() > result.m_fraction)
                col1->setHitFraction(result.m_fraction);
 
            if (resultFraction > result.m_fraction)
                resultFraction = result.m_fraction;
        }
    }

    {
        btConvexShape* convex1 = static_cast<btConvexShape*>(col1->getCollisionShape());
 
        btSphereShape sphere0(col0->getCcdSweptSphereRadius());  //todo: allow non-zero sphere sizes, for better approximation
        btConvexCast::CastResult result;
        btVoronoiSimplexSolver voronoiSimplex;
        //SubsimplexConvexCast ccd0(&sphere,min0,&voronoiSimplex);
        btGjkConvexCast ccd1(&sphere0, convex1, &voronoiSimplex);
        //ContinuousConvexCollision ccd(min0,min1,&voronoiSimplex,0);
        if (ccd1.calcTimeOfImpact(col0->getWorldTransform(), col0->getInterpolationWorldTransform(),
                                  col1->getWorldTransform(), col1->getInterpolationWorldTransform(), result))
        {
            //store result.m_fraction in both bodies
 
            if (col0->getHitFraction() > result.m_fraction)
                col0->setHitFraction(result.m_fraction);
 
            if (col1->getHitFraction() > result.m_fraction)
                col1->setHitFraction(result.m_fraction);
 
            if (resultFraction > result.m_fraction)
                resultFraction = result.m_fraction;
        }
    }
 
    return resultFraction;
}