more efficient ParticleTree::getParticles() and adding ParticleTree::getParticlesForUpdate()

libraries/particles/src/ParticleTree.cpp

@@ -170,16 +170,14 @@ public:
 
 bool ParticleTree::findInSphereOperation(OctreeElement* element, void* extraData) {
     FindAllNearPointArgs* args = static_cast<FindAllNearPointArgs*>(extraData);
-    ParticleTreeElement* particleTreeElement = static_cast<ParticleTreeElement*>(element);
-
     glm::vec3 penetration;
-    bool sphereIntersection = particleTreeElement->getAABox().findSpherePenetration(args->position,
+    bool sphereIntersection = element->getAABox().findSpherePenetration(args->position,
                                                                     args->targetRadius, penetration);
 
-    // If this particleTreeElement contains the point, then search it...
+    // If this element contains the point, then search it...
     if (sphereIntersection) {
-        QVector<const Particle*> moreParticles = particleTreeElement->getParticles(args->position, args->targetRadius);
-        args->particles << moreParticles;
+        ParticleTreeElement* particleTreeElement = static_cast<ParticleTreeElement*>(element);
+        particleTreeElement->getParticles(args->position, args->targetRadius, args->particles);
         return true; // keep searching in case children have closer particles
     }
 
@@ -187,13 +185,43 @@ bool ParticleTree::findInSphereOperation(OctreeElement* element, void* extraData
     return false;
 }
 
-QVector<const Particle*> ParticleTree::findParticles(const glm::vec3& center, float radius) {
-    QVector<Particle*> result;
+void ParticleTree::findParticles(const glm::vec3& center, float radius, QVector<const Particle*>& foundParticles) {
     FindAllNearPointArgs args = { center, radius };
     lockForRead();
     recurseTreeWithOperation(findInSphereOperation, &args);
     unlock();
-    return args.particles;
+    // swap the two lists of particle pointers instead of copy
+    foundParticles.swap(args.particles);
+}
+
+class FindParticlesInBoxArgs {
+public:
+    FindParticlesInBoxArgs(const AABox& box) 
+        : _box(box), _foundParticles() {
+    }
+
+    AABox _box;
+    QVector<Particle*> _foundParticles;
+};
+
+bool findInBoxForUpdateOperation(OctreeElement* element, void* extraData) {
+    FindParticlesInBoxArgs* args = static_cast< FindParticlesInBoxArgs*>(extraData);
+    const AABox& elementBox = element->getAABox();
+    if (elementBox.touches(args->_box)) {
+        ParticleTreeElement* particleTreeElement = static_cast<ParticleTreeElement*>(element);
+        particleTreeElement->getParticlesForUpdate(args->_box, args->_foundParticles);
+        return true;
+    }
+    return false;
+}
+
+void ParticleTree::findParticlesForUpdate(const AABox& box, QVector<Particle*> foundParticles) {
+    FindParticlesInBoxArgs args(box);
+    lockForRead();
+    recurseTreeWithOperation(findInBoxForUpdateOperation, &args);
+    unlock();
+    // swap the two lists of particle pointers instead of copy
+    foundParticles.swap(args._foundParticles);
 }
 
 class FindByIDArgs {
@@ -495,31 +523,3 @@ void ParticleTree::processEraseMessage(const QByteArray& dataByteArray, const Hi
         recurseTreeWithOperation(findAndDeleteOperation, &args);
     }
 }
-
-class FindParticlesArgs {
-public:
-    FindParticlesArgs(const AABox& box) 
-        : _box(box), _foundParticles() {
-    }
-
-    AABox _box;
-    QVector<Particle*> _foundParticles;
-};
-
-bool findOperation(OctreeElement* element, void* extraData) {
-    FindParticlesArgs* args = static_cast< FindParticlesArgs*>(extraData);
-    const AABox& elementBox = element->getAABox();
-    if (elementBox.touches(args->_box)) {
-        ParticleTreeElement* particleTreeElement = static_cast<ParticleTreeElement*>(element);
-        particleTreeElement->findParticles(args->_box, args->_foundParticles);
-        return true;
-    }
-    return false;
-}
-
-void ParticleTree::findParticles(const AABox& box, QVector<Particle*> foundParticles) {
-    FindParticlesArgs args(box);
-    recurseTreeWithOperation(findOperation, &args);
-    // swap the two lists of particle pointers instead of copy
-    foundParticles.swap(args._foundParticles);
-}

libraries/particles/src/ParticleTree.h

@@ -42,7 +42,19 @@ public:
     void storeParticle(const Particle& particle, Node* senderNode = NULL);
     const Particle* findClosestParticle(glm::vec3 position, float targetRadius);
     const Particle* findParticleByID(uint32_t id, bool alreadyLocked = false);
-    QVector<const Particle*> findParticles(const glm::vec3& center, float radius);
+
+    /// finds all particles that touch a sphere
+    /// \param center the center of the sphere
+    /// \param radius the radius of the sphere
+    /// \param foundParticles[out] vector of const Particle*
+    /// \remark Side effect: any initial contents in foundParticles will be lost
+    void findParticles(const glm::vec3& center, float radius, QVector<const Particle*>& foundParticles);
+
+    /// finds all particles that touch a box
+    /// \param box the query box
+    /// \param foundParticles[out] vector of non-const Particle*
+    /// \remark Side effect: any initial contents in particles will be lost
+    void findParticlesForUpdate(const AABox& box, QVector<Particle*> foundParticles);
 
     void addNewlyCreatedHook(NewlyCreatedParticleHook* hook);
     void removeNewlyCreatedHook(NewlyCreatedParticleHook* hook);
@@ -54,12 +66,6 @@ public:
 
     void processEraseMessage(const QByteArray& dataByteArray, const HifiSockAddr& senderSockAddr, Node* sourceNode);
 
-    /// finds all particles that touch a box
-    /// \param box the query box
-    /// \param particles[out] vector of Particle pointer
-    /// \remark Side effect: any initial contents in particles will be lost
-    void findParticles(const AABox& box, QVector<Particle*> particles);
-
 private:
 
     static bool updateOperation(OctreeElement* element, void* extraData);

libraries/particles/src/ParticleTreeElement.cpp

@@ -185,21 +185,34 @@ const Particle* ParticleTreeElement::getClosestParticle(glm::vec3 position) cons
     return closestParticle;
 }
 
-QVector<const Particle*> ParticleTreeElement::getParticles(glm::vec3 searchPosition, float searchRadius) const {
-    QVector<const Particle*> results;
+void ParticleTreeElement::getParticles(const glm::vec3& searchPosition, float searchRadius, QVector<const Particle*>& foundParticles) const {
     uint16_t numberOfParticles = _particles->size();
     for (uint16_t i = 0; i < numberOfParticles; i++) {
         const Particle* particle = &(*_particles)[i];
         glm::vec3 particlePosition = particle->getPosition();
-        float particleRadius = particle->getRadius();
-        glm::vec3 penetration;
-
-        // check to see that the particle (penetrator) penetrates the search area
-        if (findSphereSpherePenetration(particlePosition, particleRadius, searchPosition, searchRadius, penetration)) {
-            results << particle;
+        float distance = glm::length(particle->getPosition() - searchPosition);
+        if (distance < searchRadius + particle->getRadius()) {
+            foundParticles.push_back(particle);
         }
     }
-    return results;
+}
+
+void ParticleTreeElement::getParticlesForUpdate(const AABox& box, QVector<Particle*>& foundParticles) {
+    QList<Particle>::iterator particleItr = _particles->begin();
+    QList<Particle>::iterator particleEnd = _particles->end();
+    AABox particleBox;
+    while(particleItr != particleEnd) {
+        Particle* particle = &(*particleItr);
+        float radius = particle->getRadius();
+        // NOTE: we actually do box-box collision queries here, which is sloppy but good enough for now
+        // TODO: decide whether to replace particleBox-box query with sphere-box (requires a square root
+        // but will be slightly more accurate).
+        particleBox.setBox(particle->getPosition() - glm::vec3(radius), 2.f * radius);
+        if (particleBox.touches(_box)) {
+            foundParticles.push_back(particle);
+        }
+        ++particleItr;
+    }
 }
 
 const Particle* ParticleTreeElement::getParticleWithID(uint32_t id) const {
@@ -228,22 +241,6 @@ bool ParticleTreeElement::removeParticleWithID(uint32_t id) {
     return foundParticle;
 }
 
-void ParticleTreeElement::findParticles(const AABox& box, QVector<Particle*>& foundParticles) {
-    QList<Particle>::iterator particleItr = _particles->begin();
-    QList<Particle>::iterator particleEnd = _particles->end();
-    AABox particleBox;
-    while(particleItr != particleEnd) {
-        Particle* particle = &(*particleItr);
-        float radius = particle->getRadius();
-        particleBox.setBox(particle->getPosition() - glm::vec3(radius), 2.f * radius);
-        // TODO: replace particleBox-box query with sphere-box
-        if (particleBox.touches(_box)) {
-            foundParticles.push_back(particle);
-        }
-        ++particleItr;
-    }
-}
-
 int ParticleTreeElement::readElementDataFromBuffer(const unsigned char* data, int bytesLeftToRead,
             ReadBitstreamToTreeParams& args) {
 

libraries/particles/src/ParticleTreeElement.h

@@ -89,15 +89,21 @@ public:
     bool containsParticle(const Particle& particle) const;
     bool updateParticle(const Particle& particle);
     const Particle* getClosestParticle(glm::vec3 position) const;
-    QVector<const Particle*> getParticles(glm::vec3 position, float radius) const;
-    const Particle* getParticleWithID(uint32_t id) const;
 
-    bool removeParticleWithID(uint32_t id);
+    /// finds all particles that touch a sphere
+    /// \param position the center of the query sphere
+    /// \param radius the radius of the query sphere
+    /// \param particles[out] vector of const Particle*
+    void getParticles(const glm::vec3& position, float radius, QVector<const Particle*>& foundParticles) const;
 
     /// finds all particles that touch a box
     /// \param box the query box
-    /// \param particles[out] vector of Particle pointers
-    void findParticles(const AABox& box, QVector<Particle*>& foundParticles);
+    /// \param particles[out] vector of non-const Particle*
+    void getParticlesForUpdate(const AABox& box, QVector<Particle*>& foundParticles);
+
+    const Particle* getParticleWithID(uint32_t id) const;
+
+    bool removeParticleWithID(uint32_t id);
 
 protected:
     virtual void init(unsigned char * octalCode);

libraries/particles/src/ParticlesScriptingInterface.cpp

@@ -150,7 +150,8 @@ ParticleID ParticlesScriptingInterface::findClosestParticle(const glm::vec3& cen
 QVector<ParticleID> ParticlesScriptingInterface::findParticles(const glm::vec3& center, float radius) const {
     QVector<ParticleID> result;
     if (_particleTree) {
-        QVector<const Particle*> particles = _particleTree->findParticles(center/(float)TREE_SCALE, radius/(float)TREE_SCALE);
+        QVector<const Particle*> particles;
+        _particleTree->findParticles(center/(float)TREE_SCALE, radius/(float)TREE_SCALE, particles);
 
         foreach (const Particle* particle, particles) {
             ParticleID thisParticleID(particle->getID(), UNKNOWN_TOKEN, true);