//// ParticleSystem.cpp// hifi//// Created by Jeffrey on July 10, 2013// #include <glm/glm.hpp>#include "InterfaceConfig.h"#include <SharedUtil.h>#include "ParticleSystem.h"#include "Application.h" const float DEFAULT_PARTICLE_RADIUS = 0.01f;const float DEFAULT_PARTICLE_BOUNCE = 1.0f;const float DEFAULT_PARTICLE_AIR_FRICTION = 2.0f;const float DEFAULT_PARTICLE_LIFESPAN = 1.0f;const int DEFAULT_PARTICLE_SPHERE_RESOLUTION = 6; ParticleSystem::ParticleSystem() { _numEmitters = 0; _numParticles = 0; _upDirection = glm::vec3(0.0f, 1.0f, 0.0f); // default for (unsigned int emitterIndex = 0; emitterIndex < MAX_EMITTERS; emitterIndex++) { Emitter e = _emitter[emitterIndex]; e.position = glm::vec3(0.0f, 0.0f, 0.0f); e.direction = glm::vec3(0.0f, 1.0f, 0.0f); e.visible = false; e.particleResolution = DEFAULT_PARTICLE_SPHERE_RESOLUTION; e.particleLifespan = DEFAULT_PARTICLE_LIFESPAN; e.showingBaseParticle = false; e.emitReserve = 0.0; e.thrust = 0.0f; e.rate = 0.0f; e.currentParticle = 0; e.particleRenderStyle = PARTICLE_RENDER_STYLE_SPHERE; for (int lifeStage = 0; lifeStage<NUM_PARTICLE_LIFE_STAGES; lifeStage++) { ParticleAttributes * a = &_emitter[emitterIndex].particleAttributes[lifeStage]; a->radius = DEFAULT_PARTICLE_RADIUS; a->color = glm::vec4(0.0f, 0.0f, 0.0f, 0.0f); a->bounce = DEFAULT_PARTICLE_BOUNCE; a->airFriction = DEFAULT_PARTICLE_AIR_FRICTION; a->gravity = 0.0f; a->jitter = 0.0f; a->emitterAttraction = 0.0f; a->tornadoForce = 0.0f; a->neighborAttraction = 0.0f; a->neighborRepulsion = 0.0f; a->collisionSphereRadius = 0.0f; a->collisionSpherePosition = glm::vec3(0.0f, 0.0f, 0.0f); a->usingCollisionSphere = false; } }; for (unsigned int p = 0; p < MAX_PARTICLES; p++) { _particle[p].alive = false; _particle[p].age = 0.0f; _particle[p].radius = 0.0f; _particle[p].emitterIndex = 0; _particle[p].previousParticle = -1; _particle[p].position = glm::vec3(0.0f, 0.0f, 0.0f); _particle[p].velocity = glm::vec3(0.0f, 0.0f, 0.0f); } } int ParticleSystem::addEmitter() { if (_numEmitters < MAX_EMITTERS) { _numEmitters ++; return _numEmitters - 1; } return -1;} void ParticleSystem::simulate(float deltaTime) { // emit particles for (int e = 0; e < _numEmitters; e++) { assert( e >= 0 ); assert( e <= MAX_EMITTERS ); assert( _emitter[e].rate >= 0 ); _emitter[e].emitReserve += _emitter[e].rate * deltaTime; int numParticlesEmittedThisTime = (int)_emitter[e].emitReserve; _emitter[e].emitReserve -= numParticlesEmittedThisTime; for (int p = 0; p < numParticlesEmittedThisTime; p++) { createParticle(e); } } // update particles for (unsigned int p = 0; p < _numParticles; p++) { if (_particle[p].alive) { if (_particle[p].age > _emitter[_particle[p].emitterIndex].particleLifespan) { killParticle(p); } else { updateParticle(p, deltaTime); } } }} void ParticleSystem::createParticle(int e) { for (unsigned int p = 0; p < MAX_PARTICLES; p++) { if (!_particle[p].alive) { _particle[p].emitterIndex = e; _particle[p].alive = true; _particle[p].age = 0.0f; _particle[p].velocity = _emitter[e].direction * _emitter[e].thrust; _particle[p].position = _emitter[e].position; _particle[p].radius = _emitter[e].particleAttributes[0].radius; _particle[p].color = _emitter[e].particleAttributes[0].color; _particle[p].previousParticle = -1; if ( _particle[_emitter[e].currentParticle].alive) { if (_particle[_emitter[e].currentParticle].emitterIndex == e ) { _particle[p].previousParticle = _emitter[e].currentParticle; } } _emitter[e].currentParticle = p; _numParticles ++; assert(_numParticles <= MAX_PARTICLES); break; } }} void ParticleSystem::killParticle(int p) { assert( p >= 0); assert( p < MAX_PARTICLES); assert( _numParticles > 0); _particle[p].alive = false; _particle[p].previousParticle = -1; _particle[p].position = _emitter[_particle[p].emitterIndex].position; _particle[p].velocity = glm::vec3(0.0f, 0.0f, 0.0f); _particle[p].age = 0.0f; _particle[p].emitterIndex = -1; _numParticles --; } void ParticleSystem::setParticleAttributes(int emitterIndex, ParticleAttributes attributes) { for (int lifeStage = 0; lifeStage < NUM_PARTICLE_LIFE_STAGES; lifeStage ++ ) { setParticleAttributes(emitterIndex, (ParticleLifeStage)lifeStage, attributes); }} void ParticleSystem::setParticleAttributes(int emitterIndex, ParticleLifeStage lifeStage, ParticleAttributes attributes) { ParticleAttributes * a = &_emitter[emitterIndex].particleAttributes[lifeStage]; a->radius = attributes.radius; a->color = attributes.color; a->bounce = attributes.bounce; a->gravity = attributes.gravity; a->airFriction = attributes.airFriction; a->jitter = attributes.jitter; a->emitterAttraction = attributes.emitterAttraction; a->tornadoForce = attributes.tornadoForce; a->neighborAttraction = attributes.neighborAttraction; a->neighborRepulsion = attributes.neighborRepulsion; a->usingCollisionSphere = attributes.usingCollisionSphere; a->collisionSpherePosition = attributes.collisionSpherePosition; a->collisionSphereRadius = attributes.collisionSphereRadius;} void ParticleSystem::updateParticle(int p, float deltaTime) { if (_emitter[_particle[p].emitterIndex].particleLifespan > 0.0) { Emitter myEmitter = _emitter[_particle[p].emitterIndex]; assert(_particle[p].age <= myEmitter.particleLifespan); float ageFraction = _particle[p].age / myEmitter.particleLifespan; int lifeStage = (int)( ageFraction * (NUM_PARTICLE_LIFE_STAGES-1) ); float lifeStageFraction = ageFraction * ( NUM_PARTICLE_LIFE_STAGES - 1 ) - lifeStage; _particle[p].radius = myEmitter.particleAttributes[lifeStage ].radius * (1.0f - lifeStageFraction) + myEmitter.particleAttributes[lifeStage+1].radius * lifeStageFraction; _particle[p].color = myEmitter.particleAttributes[lifeStage ].color * (1.0f - lifeStageFraction) + myEmitter.particleAttributes[lifeStage+1].color * lifeStageFraction; // apply random jitter float j = myEmitter.particleAttributes[lifeStage].jitter; _particle[p].velocity += glm::vec3 ( -j * ONE_HALF + j * randFloat(), -j * ONE_HALF + j * randFloat(), -j * ONE_HALF + j * randFloat() ) * deltaTime; // apply attraction to home position glm::vec3 vectorToHome = myEmitter.position - _particle[p].position; _particle[p].velocity += vectorToHome * myEmitter.particleAttributes[lifeStage].emitterAttraction * deltaTime; // apply neighbor attraction int neighbor = p + 1; if (neighbor == _numParticles ) { neighbor = 0; } if ( _particle[neighbor].emitterIndex == _particle[p].emitterIndex) { glm::vec3 vectorToNeighbor = _particle[p].position - _particle[neighbor].position; _particle[p].velocity -= vectorToNeighbor * myEmitter.particleAttributes[lifeStage].neighborAttraction * deltaTime; float distanceToNeighbor = glm::length(vectorToNeighbor); if (distanceToNeighbor > 0.0f) { _particle[neighbor].velocity += (vectorToNeighbor / ( 1.0f + distanceToNeighbor * distanceToNeighbor)) * myEmitter.particleAttributes[lifeStage].neighborRepulsion * deltaTime; } } // apply tornado force glm::vec3 tornadoDirection = glm::cross(vectorToHome, myEmitter.direction); _particle[p].velocity += tornadoDirection * myEmitter.particleAttributes[lifeStage].tornadoForce * deltaTime; // apply air friction float drag = 1.0 - myEmitter.particleAttributes[lifeStage].airFriction * deltaTime; if (drag < 0.0f) { _particle[p].velocity = glm::vec3(0.0f, 0.0f, 0.0f); } else { _particle[p].velocity *= drag; } // apply gravity _particle[p].velocity -= _upDirection * myEmitter.particleAttributes[lifeStage].gravity * deltaTime; // update position by velocity _particle[p].position += _particle[p].velocity; // collision with ground if (_particle[p].position.y < _particle[p].radius) { _particle[p].position.y = _particle[p].radius; if (_particle[p].velocity.y < 0.0f) { _particle[p].velocity.y *= -myEmitter.particleAttributes[lifeStage].bounce; } } // collision with sphere if (myEmitter.particleAttributes[lifeStage].usingCollisionSphere) { glm::vec3 vectorToSphereCenter = myEmitter.particleAttributes[lifeStage].collisionSpherePosition - _particle[p].position; float distanceToSphereCenter = glm::length(vectorToSphereCenter); float combinedRadius = myEmitter.particleAttributes[lifeStage].collisionSphereRadius + _particle[p].radius; if (distanceToSphereCenter < combinedRadius) { if (distanceToSphereCenter > 0.0f){ glm::vec3 directionToSphereCenter = vectorToSphereCenter / distanceToSphereCenter; _particle[p].position = myEmitter.particleAttributes[lifeStage].collisionSpherePosition - directionToSphereCenter * combinedRadius; } } } } // do this at the end... _particle[p].age += deltaTime; } void ParticleSystem::killAllParticles() { for (int e = 0; e < _numEmitters; e++) { _emitter[e].currentParticle = -1; _emitter[e].emitReserve = 0.0f; } for (unsigned int p = 0; p < _numParticles; p++) { killParticle(p); }} void ParticleSystem::render() { // render the emitters for (int e = 0; e < _numEmitters; e++) { if (_emitter[e].showingBaseParticle) { glColor4f(_particle[0].color.r, _particle[0].color.g, _particle[0].color.b, _particle[0].color.a ); glPushMatrix(); glTranslatef(_emitter[e].position.x, _emitter[e].position.y, _emitter[e].position.z); glutSolidSphere(_particle[0].radius, _emitter[e].particleResolution, _emitter[e].particleResolution); glPopMatrix(); } if (_emitter[e].visible) { renderEmitter(e, 0.2f); } }; // render the particles for (unsigned int p = 0; p < _numParticles; p++) { if (_particle[p].alive) { if (_emitter[_particle[p].emitterIndex].particleLifespan > 0.0) { renderParticle(p); } } }} void ParticleSystem::renderParticle(int p) { glColor4f(_particle[p].color.r, _particle[p].color.g, _particle[p].color.b, _particle[p].color.a ); if (_emitter[_particle[p].emitterIndex].particleRenderStyle == PARTICLE_RENDER_STYLE_BILLBOARD) { glm::vec3 cameraPosition = Application::getInstance()->getCamera()->getPosition(); glm::vec3 viewVector = _particle[p].position - cameraPosition; float distance = glm::length(viewVector); if (distance >= 0.0f) { viewVector /= distance; glm::vec3 up = glm::vec3(viewVector.y, viewVector.z, viewVector.x); glm::vec3 right = glm::vec3(viewVector.z, viewVector.x, viewVector.y); glm::vec3 p0 = _particle[p].position - right * _particle[p].radius - up * _particle[p].radius; glm::vec3 p1 = _particle[p].position + right * _particle[p].radius - up * _particle[p].radius; glm::vec3 p2 = _particle[p].position + right * _particle[p].radius + up * _particle[p].radius; glm::vec3 p3 = _particle[p].position - right * _particle[p].radius + up * _particle[p].radius; glBegin(GL_TRIANGLES); glVertex3f(p0.x, p0.y, p0.z); glVertex3f(p1.x, p1.y, p1.z); glVertex3f(p2.x, p2.y, p2.z); glEnd(); glBegin(GL_TRIANGLES); glVertex3f(p0.x, p0.y, p0.z); glVertex3f(p2.x, p2.y, p2.z); glVertex3f(p3.x, p3.y, p3.z); glEnd(); } } else if (_emitter[_particle[p].emitterIndex].particleRenderStyle == PARTICLE_RENDER_STYLE_SPHERE) { glPushMatrix(); glTranslatef(_particle[p].position.x, _particle[p].position.y, _particle[p].position.z); glutSolidSphere(_particle[p].radius, _emitter[_particle[p].emitterIndex].particleResolution, _emitter[_particle[p].emitterIndex].particleResolution); glPopMatrix(); } else if (_emitter[_particle[p].emitterIndex].particleRenderStyle == PARTICLE_RENDER_STYLE_RIBBON) { if (_particle[p].previousParticle != -1) { if ((_particle[p].alive) && (_particle[_particle[p].previousParticle].alive) && (_particle[_particle[p].previousParticle].emitterIndex == _particle[p].emitterIndex )) { int pp = _particle[p].previousParticle; glm::vec3 v = _particle[p].position - _particle[pp].position; float distance = glm::length(v); if (distance > 0.0f) { v /= distance; glm::vec3 up = glm::normalize(glm::cross(v, _upDirection)) * _particle[p].radius; glm::vec3 right = glm::normalize(glm::cross(up, v )) * _particle[p].radius; glm::vec3 p0Left = _particle[p ].position - right; glm::vec3 p0Right = _particle[p ].position + right; glm::vec3 p0Down = _particle[p ].position - up; glm::vec3 p0Up = _particle[p ].position + up; glm::vec3 ppLeft = _particle[pp].position - right; glm::vec3 ppRight = _particle[pp].position + right; glm::vec3 ppDown = _particle[pp].position - up; glm::vec3 ppUp = _particle[pp].position + up; glBegin(GL_TRIANGLES); glVertex3f(p0Left.x, p0Left.y, p0Left.z ); glVertex3f(p0Right.x, p0Right.y, p0Right.z ); glVertex3f(ppLeft.x, ppLeft.y, ppLeft.z ); glVertex3f(p0Right.x, p0Right.y, p0Right.z ); glVertex3f(ppLeft.x, ppLeft.y, ppLeft.z ); glVertex3f(ppRight.x, ppRight.y, ppRight.z ); glVertex3f(p0Up.x, p0Up.y, p0Up.z ); glVertex3f(p0Down.x, p0Down.y, p0Down.z ); glVertex3f(ppDown.x, ppDown.y, ppDown.z ); glVertex3f(p0Up.x, p0Up.y, p0Up.z ); glVertex3f(ppUp.x, ppUp.y, ppUp.z ); glVertex3f(ppDown.x, ppDown.y, ppDown.z ); glVertex3f(p0Up.x, p0Up.y, p0Left.z ); glVertex3f(p0Right.x, p0Right.y, p0Right.z ); glVertex3f(p0Down.x, p0Down.y, p0Down.z ); glVertex3f(p0Up.x, p0Up.y, p0Left.z ); glVertex3f(p0Left.x, p0Left.y, p0Left.z ); glVertex3f(p0Down.x, p0Down.y, p0Down.z ); glVertex3f(ppUp.x, ppUp.y, ppLeft.z ); glVertex3f(ppRight.x, ppRight.y, ppRight.z ); glVertex3f(ppDown.x, ppDown.y, ppDown.z ); glVertex3f(ppUp.x, ppUp.y, ppLeft.z ); glVertex3f(ppLeft.x, ppLeft.y, ppLeft.z ); glVertex3f(ppDown.x, ppDown.y, ppDown.z ); glEnd(); } } } }} void ParticleSystem::renderEmitter(int e, float size) { glLineWidth(2.0f); glColor3f(0.4f, 0.4, 0.8); glBegin(GL_LINES); glVertex3f(_emitter[e].position.x, _emitter[e].position.y, _emitter[e].position.z); glVertex3f(_emitter[e].position.x + _emitter[e].direction.x, _emitter[e].position.y + _emitter[e].direction.y, _emitter[e].position.z + _emitter[e].direction.z); glEnd();}
//
// ParticleSystem.cpp
// hifi
//
// Created by Jeffrey on July 10, 2013
//
#include <glm/glm.hpp>
#include "InterfaceConfig.h"
#include <SharedUtil.h>
#include "ParticleSystem.h"
#include "Application.h"
const float DEFAULT_PARTICLE_RADIUS = 0.01f;
const float DEFAULT_PARTICLE_BOUNCE = 1.0f;
const float DEFAULT_PARTICLE_AIR_FRICTION = 2.0f;
const float DEFAULT_PARTICLE_LIFESPAN = 1.0f;
const int DEFAULT_PARTICLE_SPHERE_RESOLUTION = 6;
ParticleSystem::ParticleSystem() {
_numEmitters = 0;
_numParticles = 0;
_upDirection = glm::vec3(0.0f, 1.0f, 0.0f); // default
for (unsigned int emitterIndex = 0; emitterIndex < MAX_EMITTERS; emitterIndex++) {
Emitter e = _emitter[emitterIndex];
e.position = glm::vec3(0.0f, 0.0f, 0.0f);
e.direction = glm::vec3(0.0f, 1.0f, 0.0f);
e.visible = false;
e.particleResolution = DEFAULT_PARTICLE_SPHERE_RESOLUTION;
e.particleLifespan = DEFAULT_PARTICLE_LIFESPAN;
e.showingBaseParticle = false;
e.emitReserve = 0.0;
e.thrust = 0.0f;
e.rate = 0.0f;
e.currentParticle = 0;
e.particleRenderStyle = PARTICLE_RENDER_STYLE_SPHERE;
for (int lifeStage = 0; lifeStage<NUM_PARTICLE_LIFE_STAGES; lifeStage++) {
ParticleAttributes * a = &_emitter[emitterIndex].particleAttributes[lifeStage];
a->radius = DEFAULT_PARTICLE_RADIUS;
a->color = glm::vec4(0.0f, 0.0f, 0.0f, 0.0f);
a->bounce = DEFAULT_PARTICLE_BOUNCE;
a->airFriction = DEFAULT_PARTICLE_AIR_FRICTION;
a->gravity = 0.0f;
a->jitter = 0.0f;
a->emitterAttraction = 0.0f;
a->tornadoForce = 0.0f;
a->neighborAttraction = 0.0f;
a->neighborRepulsion = 0.0f;
a->collisionSphereRadius = 0.0f;
a->collisionSpherePosition = glm::vec3(0.0f, 0.0f, 0.0f);
a->usingCollisionSphere = false;
}
};
for (unsigned int p = 0; p < MAX_PARTICLES; p++) {
_particle[p].alive = false;
_particle[p].age = 0.0f;
_particle[p].radius = 0.0f;
_particle[p].emitterIndex = 0;
_particle[p].previousParticle = -1;
_particle[p].position = glm::vec3(0.0f, 0.0f, 0.0f);
_particle[p].velocity = glm::vec3(0.0f, 0.0f, 0.0f);
}
}
int ParticleSystem::addEmitter() {
if (_numEmitters < MAX_EMITTERS) {
_numEmitters ++;
return _numEmitters - 1;
}
return -1;
}
void ParticleSystem::simulate(float deltaTime) {
// emit particles
for (int e = 0; e < _numEmitters; e++) {
assert( e >= 0 );
assert( e <= MAX_EMITTERS );
assert( _emitter[e].rate >= 0 );
_emitter[e].emitReserve += _emitter[e].rate * deltaTime;
int numParticlesEmittedThisTime = (int)_emitter[e].emitReserve;
_emitter[e].emitReserve -= numParticlesEmittedThisTime;
for (int p = 0; p < numParticlesEmittedThisTime; p++) {
createParticle(e);
}
}
// update particles
for (unsigned int p = 0; p < _numParticles; p++) {
if (_particle[p].alive) {
if (_particle[p].age > _emitter[_particle[p].emitterIndex].particleLifespan) {
killParticle(p);
} else {
updateParticle(p, deltaTime);
}
}
}
}
void ParticleSystem::createParticle(int e) {
for (unsigned int p = 0; p < MAX_PARTICLES; p++) {
if (!_particle[p].alive) {
_particle[p].emitterIndex = e;
_particle[p].alive = true;
_particle[p].age = 0.0f;
_particle[p].velocity = _emitter[e].direction * _emitter[e].thrust;
_particle[p].position = _emitter[e].position;
_particle[p].radius = _emitter[e].particleAttributes[0].radius;
_particle[p].color = _emitter[e].particleAttributes[0].color;
_particle[p].previousParticle = -1;
if ( _particle[_emitter[e].currentParticle].alive) {
if (_particle[_emitter[e].currentParticle].emitterIndex == e ) {
_particle[p].previousParticle = _emitter[e].currentParticle;
}
}
_emitter[e].currentParticle = p;
_numParticles ++;
assert(_numParticles <= MAX_PARTICLES);
break;
}
}
}
void ParticleSystem::killParticle(int p) {
assert( p >= 0);
assert( p < MAX_PARTICLES);
assert( _numParticles > 0);
_particle[p].alive = false;
_particle[p].previousParticle = -1;
_particle[p].position = _emitter[_particle[p].emitterIndex].position;
_particle[p].velocity = glm::vec3(0.0f, 0.0f, 0.0f);
_particle[p].age = 0.0f;
_particle[p].emitterIndex = -1;
_numParticles --;
}
void ParticleSystem::setParticleAttributes(int emitterIndex, ParticleAttributes attributes) {
for (int lifeStage = 0; lifeStage < NUM_PARTICLE_LIFE_STAGES; lifeStage ++ ) {
setParticleAttributes(emitterIndex, (ParticleLifeStage)lifeStage, attributes);
}
}
void ParticleSystem::setParticleAttributes(int emitterIndex, ParticleLifeStage lifeStage, ParticleAttributes attributes) {
ParticleAttributes * a = &_emitter[emitterIndex].particleAttributes[lifeStage];
a->radius = attributes.radius;
a->color = attributes.color;
a->bounce = attributes.bounce;
a->gravity = attributes.gravity;
a->airFriction = attributes.airFriction;
a->jitter = attributes.jitter;
a->emitterAttraction = attributes.emitterAttraction;
a->tornadoForce = attributes.tornadoForce;
a->neighborAttraction = attributes.neighborAttraction;
a->neighborRepulsion = attributes.neighborRepulsion;
a->usingCollisionSphere = attributes.usingCollisionSphere;
a->collisionSpherePosition = attributes.collisionSpherePosition;
a->collisionSphereRadius = attributes.collisionSphereRadius;
}
void ParticleSystem::updateParticle(int p, float deltaTime) {
if (_emitter[_particle[p].emitterIndex].particleLifespan > 0.0) {
Emitter myEmitter = _emitter[_particle[p].emitterIndex];
assert(_particle[p].age <= myEmitter.particleLifespan);
float ageFraction = _particle[p].age / myEmitter.particleLifespan;
int lifeStage = (int)( ageFraction * (NUM_PARTICLE_LIFE_STAGES-1) );
float lifeStageFraction = ageFraction * ( NUM_PARTICLE_LIFE_STAGES - 1 ) - lifeStage;
_particle[p].radius
= myEmitter.particleAttributes[lifeStage ].radius * (1.0f - lifeStageFraction)
+ myEmitter.particleAttributes[lifeStage+1].radius * lifeStageFraction;
_particle[p].color
= myEmitter.particleAttributes[lifeStage ].color * (1.0f - lifeStageFraction)
+ myEmitter.particleAttributes[lifeStage+1].color * lifeStageFraction;
// apply random jitter
float j = myEmitter.particleAttributes[lifeStage].jitter;
_particle[p].velocity +=
glm::vec3
(
-j * ONE_HALF + j * randFloat(),
-j * ONE_HALF + j * randFloat(),
-j * ONE_HALF + j * randFloat()
) * deltaTime;
// apply attraction to home position
glm::vec3 vectorToHome = myEmitter.position - _particle[p].position;
_particle[p].velocity += vectorToHome * myEmitter.particleAttributes[lifeStage].emitterAttraction * deltaTime;
// apply neighbor attraction
int neighbor = p + 1;
if (neighbor == _numParticles ) {
neighbor = 0;
}
if ( _particle[neighbor].emitterIndex == _particle[p].emitterIndex) {
glm::vec3 vectorToNeighbor = _particle[p].position - _particle[neighbor].position;
_particle[p].velocity -= vectorToNeighbor * myEmitter.particleAttributes[lifeStage].neighborAttraction * deltaTime;
float distanceToNeighbor = glm::length(vectorToNeighbor);
if (distanceToNeighbor > 0.0f) {
_particle[neighbor].velocity += (vectorToNeighbor / ( 1.0f + distanceToNeighbor * distanceToNeighbor)) * myEmitter.particleAttributes[lifeStage].neighborRepulsion * deltaTime;
}
}
// apply tornado force
glm::vec3 tornadoDirection = glm::cross(vectorToHome, myEmitter.direction);
_particle[p].velocity += tornadoDirection * myEmitter.particleAttributes[lifeStage].tornadoForce * deltaTime;
// apply air friction
float drag = 1.0 - myEmitter.particleAttributes[lifeStage].airFriction * deltaTime;
if (drag < 0.0f) {
_particle[p].velocity = glm::vec3(0.0f, 0.0f, 0.0f);
} else {
_particle[p].velocity *= drag;
}
// apply gravity
_particle[p].velocity -= _upDirection * myEmitter.particleAttributes[lifeStage].gravity * deltaTime;
// update position by velocity
_particle[p].position += _particle[p].velocity;
// collision with ground
if (_particle[p].position.y < _particle[p].radius) {
_particle[p].position.y = _particle[p].radius;
if (_particle[p].velocity.y < 0.0f) {
_particle[p].velocity.y *= -myEmitter.particleAttributes[lifeStage].bounce;
}
}
// collision with sphere
if (myEmitter.particleAttributes[lifeStage].usingCollisionSphere) {
glm::vec3 vectorToSphereCenter = myEmitter.particleAttributes[lifeStage].collisionSpherePosition - _particle[p].position;
float distanceToSphereCenter = glm::length(vectorToSphereCenter);
float combinedRadius = myEmitter.particleAttributes[lifeStage].collisionSphereRadius + _particle[p].radius;
if (distanceToSphereCenter < combinedRadius) {
if (distanceToSphereCenter > 0.0f){
glm::vec3 directionToSphereCenter = vectorToSphereCenter / distanceToSphereCenter;
_particle[p].position = myEmitter.particleAttributes[lifeStage].collisionSpherePosition - directionToSphereCenter * combinedRadius;
}
}
}
}
// do this at the end...
_particle[p].age += deltaTime;
}
void ParticleSystem::killAllParticles() {
for (int e = 0; e < _numEmitters; e++) {
_emitter[e].currentParticle = -1;
_emitter[e].emitReserve = 0.0f;
}
for (unsigned int p = 0; p < _numParticles; p++) {
killParticle(p);
}
}
void ParticleSystem::render() {
// render the emitters
for (int e = 0; e < _numEmitters; e++) {
if (_emitter[e].showingBaseParticle) {
glColor4f(_particle[0].color.r, _particle[0].color.g, _particle[0].color.b, _particle[0].color.a );
glPushMatrix();
glTranslatef(_emitter[e].position.x, _emitter[e].position.y, _emitter[e].position.z);
glutSolidSphere(_particle[0].radius, _emitter[e].particleResolution, _emitter[e].particleResolution);
glPopMatrix();
}
if (_emitter[e].visible) {
renderEmitter(e, 0.2f);
}
};
// render the particles
for (unsigned int p = 0; p < _numParticles; p++) {
if (_particle[p].alive) {
if (_emitter[_particle[p].emitterIndex].particleLifespan > 0.0) {
renderParticle(p);
}
}
}
}
void ParticleSystem::renderParticle(int p) {
glColor4f(_particle[p].color.r, _particle[p].color.g, _particle[p].color.b, _particle[p].color.a );
if (_emitter[_particle[p].emitterIndex].particleRenderStyle == PARTICLE_RENDER_STYLE_BILLBOARD) {
glm::vec3 cameraPosition = Application::getInstance()->getCamera()->getPosition();
glm::vec3 viewVector = _particle[p].position - cameraPosition;
float distance = glm::length(viewVector);
if (distance >= 0.0f) {
viewVector /= distance;
glm::vec3 up = glm::vec3(viewVector.y, viewVector.z, viewVector.x);
glm::vec3 right = glm::vec3(viewVector.z, viewVector.x, viewVector.y);
glm::vec3 p0 = _particle[p].position - right * _particle[p].radius - up * _particle[p].radius;
glm::vec3 p1 = _particle[p].position + right * _particle[p].radius - up * _particle[p].radius;
glm::vec3 p2 = _particle[p].position + right * _particle[p].radius + up * _particle[p].radius;
glm::vec3 p3 = _particle[p].position - right * _particle[p].radius + up * _particle[p].radius;
glBegin(GL_TRIANGLES);
glVertex3f(p0.x, p0.y, p0.z);
glVertex3f(p1.x, p1.y, p1.z);
glVertex3f(p2.x, p2.y, p2.z);
glEnd();
glBegin(GL_TRIANGLES);
glVertex3f(p0.x, p0.y, p0.z);
glVertex3f(p2.x, p2.y, p2.z);
glVertex3f(p3.x, p3.y, p3.z);
glEnd();
}
} else if (_emitter[_particle[p].emitterIndex].particleRenderStyle == PARTICLE_RENDER_STYLE_SPHERE) {
glPushMatrix();
glTranslatef(_particle[p].position.x, _particle[p].position.y, _particle[p].position.z);
glutSolidSphere(_particle[p].radius, _emitter[_particle[p].emitterIndex].particleResolution, _emitter[_particle[p].emitterIndex].particleResolution);
glPopMatrix();
} else if (_emitter[_particle[p].emitterIndex].particleRenderStyle == PARTICLE_RENDER_STYLE_RIBBON) {
if (_particle[p].previousParticle != -1) {
if ((_particle[p].alive)
&& (_particle[_particle[p].previousParticle].alive)
&& (_particle[_particle[p].previousParticle].emitterIndex == _particle[p].emitterIndex )) {
int pp = _particle[p].previousParticle;
glm::vec3 v = _particle[p].position - _particle[pp].position;
float distance = glm::length(v);
if (distance > 0.0f) {
v /= distance;
glm::vec3 up = glm::normalize(glm::cross(v, _upDirection)) * _particle[p].radius;
glm::vec3 right = glm::normalize(glm::cross(up, v )) * _particle[p].radius;
glm::vec3 p0Left = _particle[p ].position - right;
glm::vec3 p0Right = _particle[p ].position + right;
glm::vec3 p0Down = _particle[p ].position - up;
glm::vec3 p0Up = _particle[p ].position + up;
glm::vec3 ppLeft = _particle[pp].position - right;
glm::vec3 ppRight = _particle[pp].position + right;
glm::vec3 ppDown = _particle[pp].position - up;
glm::vec3 ppUp = _particle[pp].position + up;
glBegin(GL_TRIANGLES);
glVertex3f(p0Left.x, p0Left.y, p0Left.z );
glVertex3f(p0Right.x, p0Right.y, p0Right.z );
glVertex3f(ppLeft.x, ppLeft.y, ppLeft.z );
glVertex3f(p0Right.x, p0Right.y, p0Right.z );
glVertex3f(ppLeft.x, ppLeft.y, ppLeft.z );
glVertex3f(ppRight.x, ppRight.y, ppRight.z );
glVertex3f(p0Up.x, p0Up.y, p0Up.z );
glVertex3f(p0Down.x, p0Down.y, p0Down.z );
glVertex3f(ppDown.x, ppDown.y, ppDown.z );
glVertex3f(p0Up.x, p0Up.y, p0Up.z );
glVertex3f(ppUp.x, ppUp.y, ppUp.z );
glVertex3f(ppDown.x, ppDown.y, ppDown.z );
glVertex3f(p0Up.x, p0Up.y, p0Left.z );
glVertex3f(p0Right.x, p0Right.y, p0Right.z );
glVertex3f(p0Down.x, p0Down.y, p0Down.z );
glVertex3f(p0Up.x, p0Up.y, p0Left.z );
glVertex3f(p0Left.x, p0Left.y, p0Left.z );
glVertex3f(p0Down.x, p0Down.y, p0Down.z );
glVertex3f(ppUp.x, ppUp.y, ppLeft.z );
glVertex3f(ppRight.x, ppRight.y, ppRight.z );
glVertex3f(ppDown.x, ppDown.y, ppDown.z );
glVertex3f(ppUp.x, ppUp.y, ppLeft.z );
glVertex3f(ppLeft.x, ppLeft.y, ppLeft.z );
glVertex3f(ppDown.x, ppDown.y, ppDown.z );
glEnd();
}
}
}
}
}
void ParticleSystem::renderEmitter(int e, float size) {
glLineWidth(2.0f);
glColor3f(0.4f, 0.4, 0.8);
glBegin(GL_LINES);
glVertex3f(_emitter[e].position.x, _emitter[e].position.y, _emitter[e].position.z);
glVertex3f(_emitter[e].position.x + _emitter[e].direction.x, _emitter[e].position.y + _emitter[e].direction.y, _emitter[e].position.z + _emitter[e].direction.z);
glEnd();
}