particle to particle collisions

libraries/octree/src/Octree.cpp

@@ -599,7 +599,7 @@ bool findSpherePenetrationOp(OctreeElement* element, void* extraData) {
     }
     if (element->hasContent()) {
         glm::vec3 elementPenetration;
-        if (box.findSpherePenetration(args->center, args->radius, elementPenetration)) {
+        if (element->findSpherePenetration(args->center, args->radius, elementPenetration)) {
             args->penetration = addPenetrations(args->penetration, elementPenetration * (float)TREE_SCALE);
             args->found = true;
             args->penetratedElement = element;

libraries/octree/src/OctreeElement.cpp

@@ -1285,6 +1285,11 @@ void OctreeElement::notifyUpdateHooks() {
     }
 }
 
+bool OctreeElement::findSpherePenetration(const glm::vec3& center, float radius, glm::vec3& penetration) const {
+    return _box.findSpherePenetration(center, radius, penetration);
+}
+
+
 OctreeElement* OctreeElement::getOrCreateChildElementAt(float x, float y, float z, float s) {
     OctreeElement* child = NULL;
     // If the requested size is less than or equal to our scale, but greater than half our scale, then

libraries/octree/src/OctreeElement.h

@@ -93,6 +93,8 @@ public:
     virtual bool deleteApproved() const { return true; }
 
 
+    virtual bool findSpherePenetration(const glm::vec3& center, float radius, glm::vec3& penetration) const;
+
     // Base class methods you don't need to implement
     const unsigned char* getOctalCode() const { return (_octcodePointer) ? _octalCode.pointer : &_octalCode.buffer[0]; }
     OctreeElement* getChildAtIndex(int childIndex) const;

libraries/particles/src/ParticleCollisionSystem.cpp

@@ -58,6 +58,7 @@ void ParticleCollisionSystem::update() {
 
 void ParticleCollisionSystem::checkParticle(Particle* particle) {
     updateCollisionWithVoxels(particle);
+    updateCollisionWithParticles(particle);
 }
 
 void ParticleCollisionSystem::updateCollisionWithVoxels(Particle* particle) {
@@ -75,6 +76,21 @@ void ParticleCollisionSystem::updateCollisionWithVoxels(Particle* particle) {
     }
 }
 
+void ParticleCollisionSystem::updateCollisionWithParticles(Particle* particle) {
+    glm::vec3 center = particle->getPosition() * (float)TREE_SCALE;
+    float radius = particle->getRadius() * (float)TREE_SCALE;
+    const float VOXEL_ELASTICITY = 1.4f;
+    const float VOXEL_DAMPING = 0.0;
+    const float VOXEL_COLLISION_FREQUENCY = 0.5f;
+    glm::vec3 penetration;
+    OctreeElement* penetratedElement;
+    if (_particles->findSpherePenetration(center, radius, penetration, &penetratedElement)) {
+        penetration /= (float)TREE_SCALE;
+        updateCollisionSound(particle, penetration, VOXEL_COLLISION_FREQUENCY);
+        applyHardCollision(particle, penetration, VOXEL_ELASTICITY, VOXEL_DAMPING);
+    }
+}
+
 void ParticleCollisionSystem::applyHardCollision(Particle* particle, const glm::vec3& penetration, 
                                 float elasticity, float damping) {
     //

libraries/particles/src/ParticleCollisionSystem.h

@@ -40,6 +40,7 @@ public:
     void update();
     void checkParticle(Particle* particle);
     void updateCollisionWithVoxels(Particle* particle);
+    void updateCollisionWithParticles(Particle* particle);
     void applyHardCollision(Particle* particle, const glm::vec3& penetration, float elasticity, float damping);
     void updateCollisionSound(Particle* particle, const glm::vec3 &penetration, float frequency);
 

libraries/particles/src/ParticleTreeElement.cpp

@@ -8,6 +8,8 @@
 
 #include <QtCore/QDebug>
 
+#include <GeometryUtil.h>
+
 #include "ParticleTree.h"
 #include "ParticleTreeElement.h"
 
@@ -84,6 +86,24 @@ void ParticleTreeElement::update(ParticleTreeUpdateArgs& args) {
     }
 }
 
+bool ParticleTreeElement::findSpherePenetration(const glm::vec3& center, float radius, glm::vec3& penetration) const {
+    uint16_t numberOfParticles = _particles.size();
+    for (uint16_t i = 0; i < numberOfParticles; i++) {
+        glm::vec3 particleCenter = _particles[i].getPosition();
+        float particleRadius = _particles[i].getRadius();
+        
+        // don't penetrate yourself
+        if (particleCenter == center && particleRadius == radius) {
+            return false;
+        }
+        
+        if (findSphereSpherePenetration(center, radius, particleCenter, particleRadius, penetration)) {
+            return true;
+        }
+    }
+    return false;
+}
+
 bool ParticleTreeElement::containsParticle(const Particle& particle) const {
     uint16_t numberOfParticles = _particles.size();
     for (uint16_t i = 0; i < numberOfParticles; i++) {

libraries/particles/src/ParticleTreeElement.h

@@ -70,9 +70,10 @@ public:
     /// where an element is not actually rendering all should render elements. If the isRendered() state doesn't match the
     /// shouldRender() state, the tree will remark elements as changed even in cases there the elements have not changed.
     virtual bool isRendered() const { return getShouldRender(); }
-
     virtual bool deleteApproved() const { return !hasParticles(); }
 
+    virtual bool findSpherePenetration(const glm::vec3& center, float radius, glm::vec3& penetration) const;
+
     const std::vector<Particle>& getParticles() const { return _particles; }
     std::vector<Particle>& getParticles() { return _particles; }
     bool hasParticles() const { return _particles.size() > 0; }