text: /*
  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 "LinearMath/btQuickprof.h"
  #include "btSoftMultiBodyDynamicsWorld.h"
  
  // softbody & helpers
  #include "BulletSoftBody/btDefaultSoftBodySolver.h"
  #include "BulletSoftBody/btSoftBody.h"
  #include "BulletSoftBody/btSoftBodyHelpers.h"
  #include "BulletSoftBody/btSoftBodySolvers.h"
  #include "LinearMath/btSerializer.h"
  
  btSoftMultiBodyDynamicsWorld::btSoftMultiBodyDynamicsWorld(btDispatcher *dispatcher, btBroadphaseInterface *pairCache,
                                                             btMultiBodyConstraintSolver *constraintSolver,
                                                             btCollisionConfiguration *collisionConfiguration,
                                                             btSoftBodySolver *softBodySolver)
      : btMultiBodyDynamicsWorld(dispatcher, pairCache, constraintSolver, collisionConfiguration),
        m_softBodySolver(softBodySolver), m_ownsSolver(false) {
    if (!m_softBodySolver) {
      void *ptr = btAlignedAlloc(sizeof(btDefaultSoftBodySolver), 16);
      m_softBodySolver = new (ptr) btDefaultSoftBodySolver();
      m_ownsSolver = true;
    }
  
    m_drawFlags = fDrawFlags::Std;
    m_drawNodeTree = true;
    m_drawFaceTree = false;
    m_drawClusterTree = false;
    m_sbi.m_broadphase = pairCache;
    m_sbi.m_dispatcher = dispatcher;
    m_sbi.m_sparsesdf.Initialize();
    m_sbi.m_sparsesdf.Reset();
  
    m_sbi.air_density = (btScalar)1.2;
    m_sbi.water_density = 0;
    m_sbi.water_offset = 0;
    m_sbi.water_normal = btVector3(0, 0, 0);
    m_sbi.m_gravity.setValue(0, -10, 0);
  
    m_sbi.m_sparsesdf.Initialize();
  }
  
  btSoftMultiBodyDynamicsWorld::~btSoftMultiBodyDynamicsWorld() {
    if (m_ownsSolver) {
      m_softBodySolver->~btSoftBodySolver();
      btAlignedFree(m_softBodySolver);
    }
  }
  
  void btSoftMultiBodyDynamicsWorld::predictUnconstraintMotion(btScalar timeStep) {
    btDiscreteDynamicsWorld::predictUnconstraintMotion(timeStep);
    {
      BT_PROFILE("predictUnconstraintMotionSoftBody");
      m_softBodySolver->predictMotion(float(timeStep));
    }
  }
  
  void btSoftMultiBodyDynamicsWorld::internalSingleStepSimulation(btScalar timeStep) {
    // Let the solver grab the soft bodies and if necessary optimize for it
    m_softBodySolver->optimize(getSoftBodyArray());
  
    if (!m_softBodySolver->checkInitialized()) {
      btAssert("Solver initialization failed\n");
    }
  
    btDiscreteDynamicsWorld::internalSingleStepSimulation(timeStep);
  
    /// solve soft bodies constraints
    solveSoftBodiesConstraints(timeStep);
  
    // self collisions
    for (int i = 0; i < m_softBodies.size(); i++) {
      btSoftBody *psb = (btSoftBody *)m_softBodies[i];
      psb->defaultCollisionHandler(psb);
    }
  
    /// update soft bodies
    m_softBodySolver->updateSoftBodies();
  
    for (int i = 0; i < m_softBodies.size(); i++) {
      btSoftBody *psb = (btSoftBody *)m_softBodies[i];
      psb->interpolateRenderMesh();
    }
    // End solver-wise simulation step
    // ///////////////////////////////
  }
  
  void btSoftMultiBodyDynamicsWorld::solveSoftBodiesConstraints(btScalar timeStep) {
    BT_PROFILE("solveSoftConstraints");
  
    if (m_softBodies.size()) {
      btSoftBody::solveClusters(m_softBodies);
    }
  
    // Solve constraints solver-wise
    m_softBodySolver->solveConstraints(timeStep * m_softBodySolver->getTimeScale());
  }
  
  void btSoftMultiBodyDynamicsWorld::addSoftBody(btSoftBody *body, int collisionFilterGroup, int collisionFilterMask) {
    m_softBodies.push_back(body);
  
    // Set the soft body solver that will deal with this body
    // to be the world's solver
    body->setSoftBodySolver(m_softBodySolver);
  
    btCollisionWorld::addCollisionObject(body, collisionFilterGroup, collisionFilterMask);
  }
  
  void btSoftMultiBodyDynamicsWorld::removeSoftBody(btSoftBody *body) {
    m_softBodies.remove(body);
  
    btCollisionWorld::removeCollisionObject(body);
  }
  
  void btSoftMultiBodyDynamicsWorld::removeCollisionObject(btCollisionObject *collisionObject) {
    btSoftBody *body = btSoftBody::upcast(collisionObject);
    if (body)
      removeSoftBody(body);
    else
      btDiscreteDynamicsWorld::removeCollisionObject(collisionObject);
  }
  
  void btSoftMultiBodyDynamicsWorld::debugDrawWorld() {
    btMultiBodyDynamicsWorld::debugDrawWorld();
  
    if (getDebugDrawer()) {
      int i;
      for (i = 0; i < this->m_softBodies.size(); i++) {
        btSoftBody *psb = (btSoftBody *)this->m_softBodies[i];
        if (getDebugDrawer() && (getDebugDrawer()->getDebugMode() & (btIDebugDraw::DBG_DrawWireframe))) {
          btSoftBodyHelpers::DrawFrame(psb, m_debugDrawer);
          btSoftBodyHelpers::Draw(psb, m_debugDrawer, m_drawFlags);
        }
  
        if (m_debugDrawer && (m_debugDrawer->getDebugMode() & btIDebugDraw::DBG_DrawAabb)) {
          if (m_drawNodeTree)
            btSoftBodyHelpers::DrawNodeTree(psb, m_debugDrawer);
          if (m_drawFaceTree)
            btSoftBodyHelpers::DrawFaceTree(psb, m_debugDrawer);
          if (m_drawClusterTree)
            btSoftBodyHelpers::DrawClusterTree(psb, m_debugDrawer);
        }
      }
    }
  }
  
  struct btSoftSingleRayCallback : public btBroadphaseRayCallback {
    btVector3 m_rayFromWorld;
    btVector3 m_rayToWorld;
    btTransform m_rayFromTrans;
    btTransform m_rayToTrans;
    btVector3 m_hitNormal;
  
    const btSoftMultiBodyDynamicsWorld *m_world;
    btCollisionWorld::RayResultCallback &m_resultCallback;
  
    btSoftSingleRayCallback(const btVector3 &rayFromWorld, const btVector3 &rayToWorld,
                            const btSoftMultiBodyDynamicsWorld *world,
                            btCollisionWorld::RayResultCallback &resultCallback)
        : m_rayFromWorld(rayFromWorld), m_rayToWorld(rayToWorld), m_world(world), m_resultCallback(resultCallback) {
      m_rayFromTrans.setIdentity();
      m_rayFromTrans.setOrigin(m_rayFromWorld);
      m_rayToTrans.setIdentity();
      m_rayToTrans.setOrigin(m_rayToWorld);
  
      btVector3 rayDir = (rayToWorld - rayFromWorld);
  
      rayDir.normalize();
      /// what about division by zero? --> just set rayDirection[i] to INF/1e30
      m_rayDirectionInverse[0] = rayDir[0] == btScalar(0.0) ? btScalar(1e30) : btScalar(1.0) / rayDir[0];
      m_rayDirectionInverse[1] = rayDir[1] == btScalar(0.0) ? btScalar(1e30) : btScalar(1.0) / rayDir[1];
      m_rayDirectionInverse[2] = rayDir[2] == btScalar(0.0) ? btScalar(1e30) : btScalar(1.0) / rayDir[2];
      m_signs[0] = m_rayDirectionInverse[0] < 0.0;
      m_signs[1] = m_rayDirectionInverse[1] < 0.0;
      m_signs[2] = m_rayDirectionInverse[2] < 0.0;
  
      m_lambda_max = rayDir.dot(m_rayToWorld - m_rayFromWorld);
    }
  
    virtual bool process(const btBroadphaseProxy *proxy) {
      /// terminate further ray tests, once the closestHitFraction reached zero
      if (m_resultCallback.m_closestHitFraction == btScalar(0.f))
        return false;
  
      btCollisionObject *collisionObject = (btCollisionObject *)proxy->m_clientObject;
  
      // only perform raycast if filterMask matches
      if (m_resultCallback.needsCollision(collisionObject->getBroadphaseHandle())) {
        // RigidcollisionObject* collisionObject = ctrl->GetRigidcollisionObject();
        // btVector3 collisionObjectAabbMin,collisionObjectAabbMax;
  #if 0
  #ifdef RECALCULATE_AABB
              btVector3 collisionObjectAabbMin,collisionObjectAabbMax;
              collisionObject->getCollisionShape()->getAabb(collisionObject->getWorldTransform(),collisionObjectAabbMin,collisionObjectAabbMax);
  #else
              //getBroadphase()->getAabb(collisionObject->getBroadphaseHandle(),collisionObjectAabbMin,collisionObjectAabbMax);
              const btVector3& collisionObjectAabbMin = collisionObject->getBroadphaseHandle()->m_aabbMin;
              const btVector3& collisionObjectAabbMax = collisionObject->getBroadphaseHandle()->m_aabbMax;
  #endif
  #endif
        // btScalar hitLambda = m_resultCallback.m_closestHitFraction;
        // culling already done by broadphase
        // if (btRayAabb(m_rayFromWorld,m_rayToWorld,collisionObjectAabbMin,collisionObjectAabbMax,hitLambda,m_hitNormal))
        {
          m_world->rayTestSingle(m_rayFromTrans, m_rayToTrans, collisionObject, collisionObject->getCollisionShape(),
                                 collisionObject->getWorldTransform(), m_resultCallback);
        }
      }
      return true;
    }
  };
  
  void btSoftMultiBodyDynamicsWorld::rayTest(const btVector3 &rayFromWorld, const btVector3 &rayToWorld,
                                             RayResultCallback &resultCallback) const {
    BT_PROFILE("rayTest");
    /// use the broadphase to accelerate the search for objects, based on their aabb
    /// and for each object with ray-aabb overlap, perform an exact ray test
    btSoftSingleRayCallback rayCB(rayFromWorld, rayToWorld, this, resultCallback);
  
  #ifndef USE_BRUTEFORCE_RAYBROADPHASE
    m_broadphasePairCache->rayTest(rayFromWorld, rayToWorld, rayCB);
  #else
    for (int i = 0; i < this->getNumCollisionObjects(); i++) {
      rayCB.process(m_collisionObjects[i]->getBroadphaseHandle());
    }
  #endif // USE_BRUTEFORCE_RAYBROADPHASE
  }
  
  void btSoftMultiBodyDynamicsWorld::rayTestSingle(const btTransform &rayFromTrans, const btTransform &rayToTrans,
                                                   btCollisionObject *collisionObject,
                                                   const btCollisionShape *collisionShape,
                                                   const btTransform &colObjWorldTransform,
                                                   RayResultCallback &resultCallback) {
    if (collisionShape->isSoftBody()) {
      btSoftBody *softBody = btSoftBody::upcast(collisionObject);
      if (softBody) {
        btSoftBody::sRayCast softResult;
        if (softBody->rayTest(rayFromTrans.getOrigin(), rayToTrans.getOrigin(), softResult)) {
          if (softResult.fraction <= resultCallback.m_closestHitFraction) {
            btCollisionWorld::LocalShapeInfo shapeInfo;
            shapeInfo.m_shapePart = 0;
            shapeInfo.m_triangleIndex = softResult.index;
            // get the normal
            btVector3 rayDir = rayToTrans.getOrigin() - rayFromTrans.getOrigin();
            btVector3 normal = -rayDir;
            normal.normalize();
  
            if (softResult.feature == btSoftBody::eFeature::Face) {
              normal = softBody->m_faces[softResult.index].m_normal;
              if (normal.dot(rayDir) > 0) {
                // normal always point toward origin of the ray
                normal = -normal;
              }
            }
  
            btCollisionWorld::LocalRayResult rayResult(collisionObject, &shapeInfo, normal, softResult.fraction);
            bool normalInWorldSpace = true;
            resultCallback.addSingleResult(rayResult, normalInWorldSpace);
          }
        }
      }
    } else {
      btCollisionWorld::rayTestSingle(rayFromTrans, rayToTrans, collisionObject, collisionShape, colObjWorldTransform,
                                      resultCallback);
    }
  }
  
  void btSoftMultiBodyDynamicsWorld::serializeSoftBodies(btSerializer *serializer) {
    int i;
    // serialize all collision objects
    for (i = 0; i < m_collisionObjects.size(); i++) {
      btCollisionObject *colObj = m_collisionObjects[i];
      if (colObj->getInternalType() & btCollisionObject::CO_SOFT_BODY) {
        int len = colObj->calculateSerializeBufferSize();
        btChunk *chunk = serializer->allocate(len, 1);
        const char *structType = colObj->serialize(chunk->m_oldPtr, serializer);
        serializer->finalizeChunk(chunk, structType, BT_SOFTBODY_CODE, colObj);
      }
    }
  }
  
  void btSoftMultiBodyDynamicsWorld::serialize(btSerializer *serializer) {
    serializer->startSerialization();
  
    serializeDynamicsWorldInfo(serializer);
  
    serializeSoftBodies(serializer);
  
    serializeMultiBodies(serializer);
  
    serializeRigidBodies(serializer);
  
    serializeCollisionObjects(serializer);
  
    serializeContactManifolds(serializer);
  
    serializer->finishSerialization();
  }
  