diff --git a/libraries/particles/src/Particle.cpp b/libraries/particles/src/Particle.cpp index 5cf5e9248d..206f075df4 100644 --- a/libraries/particles/src/Particle.cpp +++ b/libraries/particles/src/Particle.cpp @@ -668,7 +668,50 @@ void Particle::adjustEditPacketForClockSkew(unsigned char* codeColorBuffer, ssiz } } +// HALTING_* params are determined using expected acceleration of gravity over some timescale. +// This is a HACK for particles that bounce in a 1.0 gravitational field and should eventually be made more universal. +const float HALTING_PARTICLE_PERIOD = 0.0167f; // ~1/60th of a second +const float HALTING_PARTICLE_SPEED = 9.8 * HALTING_PARTICLE_PERIOD / (float)(TREE_SCALE); + +void Particle::applyHardCollision(const CollisionInfo& collisionInfo) { + // + // Update the particle in response to a hard collision. Position will be reset exactly + // to outside the colliding surface. Velocity will be modified according to elasticity. + // + // if elasticity = 0.0, collision is inelastic (vel normal to collision is lost) + // if elasticity = 1.0, collision is 100% elastic. + // + glm::vec3 position = getPosition(); + glm::vec3 velocity = getVelocity(); + + const float EPSILON = 0.0f; + glm::vec3 relativeVelocity = collisionInfo._addedVelocity - velocity; + float velocityDotPenetration = glm::dot(relativeVelocity, collisionInfo._penetration); + if (velocityDotPenetration < EPSILON) { + // particle is moving into collision surface + // + // TODO: do something smarter here by comparing the mass of the particle vs that of the other thing + // (other's mass could be stored in the Collision Info). The smaller mass should surrender more + // position offset and should slave more to the other's velocity in the static-friction case. + position -= collisionInfo._penetration; + + if (glm::length(relativeVelocity) < HALTING_PARTICLE_SPEED) { + // static friction kicks in and particle moves with colliding object + velocity = collisionInfo._addedVelocity; + } else { + glm::vec3 direction = glm::normalize(collisionInfo._penetration); + velocity += glm::dot(relativeVelocity, direction) * (1.0f + collisionInfo._elasticity) * direction; // dynamic reflection + velocity += glm::clamp(collisionInfo._damping, 0.0f, 1.0f) * (relativeVelocity - glm::dot(relativeVelocity, direction) * direction); // dynamic friction + } + } + + // change the local particle too... + setPosition(position); + setVelocity(velocity); +} + // MIN_VALID_SPEED is obtained by computing speed gained at one gravity during the shortest expected frame period +// This is a HACK for particles that bounce in a 1.0 gravitational field and should eventually be made more universal. const float MIN_EXPECTED_FRAME_PERIOD = 0.005f; // 1/200th of a second const float MIN_VALID_SPEED = 9.8 * MIN_EXPECTED_FRAME_PERIOD / (float)(TREE_SCALE); diff --git a/libraries/particles/src/Particle.h b/libraries/particles/src/Particle.h index e534c7b418..96e58f0693 100644 --- a/libraries/particles/src/Particle.h +++ b/libraries/particles/src/Particle.h @@ -16,6 +16,7 @@ #include #include +#include #include #include @@ -240,6 +241,8 @@ public: static void adjustEditPacketForClockSkew(unsigned char* codeColorBuffer, ssize_t length, int clockSkew); + void applyHardCollision(const CollisionInfo& collisionInfo); + void update(const uint64_t& now); void collisionWithParticle(Particle* other); void collisionWithVoxel(VoxelDetail* voxel); diff --git a/libraries/particles/src/ParticleCollisionSystem.cpp b/libraries/particles/src/ParticleCollisionSystem.cpp index 7e8866e7d4..d2eb291a9d 100644 --- a/libraries/particles/src/ParticleCollisionSystem.cpp +++ b/libraries/particles/src/ParticleCollisionSystem.cpp @@ -73,6 +73,8 @@ void ParticleCollisionSystem::updateCollisionWithVoxels(Particle* particle) { const float DAMPING = 0.05f; const float COLLISION_FREQUENCY = 0.5f; CollisionInfo collisionInfo; + collisionInfo._damping = DAMPING; + collisionInfo._elasticity = ELASTICITY; VoxelDetail* voxelDetails = NULL; if (_voxels->findSpherePenetration(center, radius, collisionInfo._penetration, (void**)&voxelDetails)) { @@ -81,7 +83,8 @@ void ParticleCollisionSystem::updateCollisionWithVoxels(Particle* particle) { updateCollisionSound(particle, collisionInfo._penetration, COLLISION_FREQUENCY); collisionInfo._penetration /= (float)(TREE_SCALE); - applyHardCollision(particle, ELASTICITY, DAMPING, collisionInfo); + particle->applyHardCollision(collisionInfo); + queueParticlePropertiesUpdate(particle); delete voxelDetails; // cleanup returned details } @@ -161,6 +164,8 @@ void ParticleCollisionSystem::updateCollisionWithAvatars(Particle* particle) { if (_selfAvatar) { AvatarData* avatar = (AvatarData*)_selfAvatar; CollisionInfo collisionInfo; + collisionInfo._damping = DAMPING; + collisionInfo._elasticity = ELASTICITY; if (avatar->findSphereCollision(center, radius, collisionInfo)) { collisionInfo._addedVelocity /= (float)(TREE_SCALE); glm::vec3 relativeVelocity = collisionInfo._addedVelocity - particle->getVelocity(); @@ -185,7 +190,8 @@ void ParticleCollisionSystem::updateCollisionWithAvatars(Particle* particle) { updateCollisionSound(particle, collisionInfo._penetration, COLLISION_FREQUENCY); collisionInfo._penetration /= (float)(TREE_SCALE); - applyHardCollision(particle, elasticity, damping, collisionInfo); + particle->applyHardCollision(collisionInfo); + queueParticlePropertiesUpdate(particle); } } } @@ -224,51 +230,14 @@ void ParticleCollisionSystem::updateCollisionWithAvatars(Particle* particle) { // } } -// TODO: convert applyHardCollision() to take a CollisionInfo& instead of penetration + addedVelocity -void ParticleCollisionSystem::applyHardCollision(Particle* particle, float elasticity, float damping, const CollisionInfo& collisionInfo) { - // - // Update the particle in response to a hard collision. Position will be reset exactly - // to outside the colliding surface. Velocity will be modified according to elasticity. - // - // if elasticity = 0.0, collision is inelastic (vel normal to collision is lost) - // if elasticity = 1.0, collision is 100% elastic. - // - glm::vec3 position = particle->getPosition(); - glm::vec3 velocity = particle->getVelocity(); - - const float EPSILON = 0.0f; - glm::vec3 relativeVelocity = collisionInfo._addedVelocity - velocity; - float velocityDotPenetration = glm::dot(relativeVelocity, collisionInfo._penetration); - if (velocityDotPenetration < EPSILON) { - // particle is moving into collision surface - position -= collisionInfo._penetration; - - if (glm::length(relativeVelocity) < HALTING_SPEED) { - // static friction kicks in and particle moves with colliding object - velocity = collisionInfo._addedVelocity; - } else { - glm::vec3 direction = glm::normalize(collisionInfo._penetration); - velocity += glm::dot(relativeVelocity, direction) * (1.0f + elasticity) * direction; // dynamic reflection - velocity += glm::clamp(damping, 0.0f, 1.0f) * (relativeVelocity - glm::dot(relativeVelocity, direction) * direction); // dynamic friction - } - } - const bool wantDebug = false; - if (wantDebug) { - printf("ParticleCollisionSystem::applyHardCollision() particle id:%d new velocity:%f,%f,%f inHand:%s\n", - particle->getID(), velocity.x, velocity.y, velocity.z, debug::valueOf(particle->getInHand())); - } - - // send off the result to the particle server +void ParticleCollisionSystem::queueParticlePropertiesUpdate(Particle* particle) { + // queue the result for sending to the particle server ParticleProperties properties; ParticleID particleID(particle->getID()); properties.copyFromParticle(*particle); - properties.setPosition(position * (float)TREE_SCALE); - properties.setVelocity(velocity * (float)TREE_SCALE); + properties.setPosition(particle->getPosition() * (float)TREE_SCALE); + properties.setVelocity(particle->getVelocity() * (float)TREE_SCALE); _packetSender->queueParticleEditMessage(PACKET_TYPE_PARTICLE_ADD_OR_EDIT, particleID, properties); - - // change the local particle too... - particle->setPosition(position); - particle->setVelocity(velocity); } diff --git a/libraries/particles/src/ParticleCollisionSystem.h b/libraries/particles/src/ParticleCollisionSystem.h index cf52d01a7a..b96d3f07f3 100644 --- a/libraries/particles/src/ParticleCollisionSystem.h +++ b/libraries/particles/src/ParticleCollisionSystem.h @@ -47,7 +47,7 @@ public: void updateCollisionWithVoxels(Particle* particle); void updateCollisionWithParticles(Particle* particle); void updateCollisionWithAvatars(Particle* particle); - void applyHardCollision(Particle* particle, float elasticity, float damping, const CollisionInfo& collisionInfo); + void queueParticlePropertiesUpdate(Particle* particle); void updateCollisionSound(Particle* particle, const glm::vec3 &penetration, float frequency); private: diff --git a/libraries/shared/src/CollisionInfo.h b/libraries/shared/src/CollisionInfo.h index 1e4801788e..38ae64e30c 100644 --- a/libraries/shared/src/CollisionInfo.h +++ b/libraries/shared/src/CollisionInfo.h @@ -13,11 +13,19 @@ class CollisionInfo { public: - CollisionInfo() : _penetration(0.f), _addedVelocity(0.f) { } + CollisionInfo() + : _damping(0.f), + _elasticity(1.f), + _penetration(0.f), + _addedVelocity(0.f) { + } + ~CollisionInfo() {} //glm::vec3 _point; //glm::vec3 _normal; + float _damping; + float _elasticity; glm::vec3 _penetration; // depth that bodyA is penetrates bodyB glm::vec3 _addedVelocity; };