////  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_BOUNCE       = 1.0f;const float DEFAULT_PARTICLE_AIR_FRICTION = 2.0f; ParticleSystem::ParticleSystem() {     _timer        = 0.0f;    _numEmitters  = 0;    _numParticles = 0;    _upDirection  = glm::vec3(0.0f, 1.0f, 0.0f); // default            for (unsigned int e = 0; e < MAX_EMITTERS; e++) {        _emitter[e].position                = glm::vec3(0.0f, 0.0f, 0.0f);        _emitter[e].rotation                = glm::quat();        _emitter[e].right                   = IDENTITY_RIGHT;        _emitter[e].up                      = IDENTITY_UP;        _emitter[e].front                   = IDENTITY_FRONT;        _emitter[e].bounce                  = DEFAULT_PARTICLE_BOUNCE;        _emitter[e].airFriction             = DEFAULT_PARTICLE_AIR_FRICTION;        _emitter[e].gravity                 = 0.0f;        _emitter[e].jitter                  = 0.0f;        _emitter[e].emitterAttraction       = 0.0f;        _emitter[e].tornadoForce            = 0.0f;        _emitter[e].neighborAttraction      = 0.0f;        _emitter[e].neighborRepulsion       = 0.0f;        _emitter[e].collisionSphereRadius   = 0.0f;        _emitter[e].collisionSpherePosition = glm::vec3(0.0f, 0.0f, 0.0f);        _emitter[e].usingCollisionSphere    = false;        _emitter[e].showingEmitter          = false;     };          for (unsigned int p = 0; p < MAX_PARTICLES; p++) {        _particle[p].alive        = false;        _particle[p].age          = 0.0f;        _particle[p].lifespan     = 0.0f;        _particle[p].radius       = 0.0f;        _particle[p].emitterIndex = 0;        _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() {     printf( "\n" );    printf( "ParticleSystem::addEmitter\n" );     _numEmitters ++;        if (_numEmitters > MAX_EMITTERS) {         printf( "Oops! _numEmitters > MAX_EMITTERS... returning -1\n" );         return -1;    }     printf( "ok, _numEmitters is %d,and the index of this newly added emitter is %d.\n", _numEmitters, _numEmitters-1 );        return _numEmitters - 1;}  void ParticleSystem::simulate(float deltaTime) {        // update emitters    for (unsigned int e = 0; e < _numEmitters; e++) {        updateEmitter(e, deltaTime);            }        runSpecialEffectsTest(0, deltaTime);          // update particles    for (unsigned int p = 0; p < _numParticles; p++) {        if (_particle[p].alive) {            updateParticle(p, deltaTime);        }    }} void ParticleSystem::updateEmitter(int e, float deltaTime) {     _emitter[e].front = _emitter[e].rotation * IDENTITY_FRONT;    _emitter[e].right = _emitter[e].rotation * IDENTITY_RIGHT;    _emitter[e].up    = _emitter[e].rotation * IDENTITY_UP;    }  void ParticleSystem::emitParticlesNow(int e, int num, float radius, glm::vec4 color, glm::vec3 velocity, float lifespan) {     for (unsigned int p = 0; p < num; p++) {        createParticle(e, _emitter[e].position, velocity, radius, color, lifespan);    }} void ParticleSystem::createParticle(int e, glm::vec3 position, glm::vec3 velocity, float radius, glm::vec4 color, float lifespan) {            for (unsigned int p = 0; p < MAX_PARTICLES; p++) {        if (!_particle[p].alive) {                    _particle[p].emitterIndex = e;                _particle[p].lifespan     = lifespan;            _particle[p].alive        = true;            _particle[p].age          = 0.0f;            _particle[p].position     = position;            _particle[p].velocity     = velocity;            _particle[p].radius       = radius;            _particle[p].color        = color;             _numParticles ++;                                                assert(_numParticles <= MAX_PARTICLES);                        return;        }    }} void ParticleSystem::killParticle(int p) {     assert( p >= 0);    assert( p < MAX_PARTICLES);    assert( _numParticles > 0);     _particle[p].alive = false;    _numParticles --;}  void ParticleSystem::setOrangeBlueColorPalette() {     for (unsigned int p = 0; p < _numParticles; p++) {         float radian = ((float)p / (float)_numParticles) * PI_TIMES_TWO;        float wave   = sinf(radian);                float red    = 0.5f + 0.5f * wave;        float green  = 0.3f + 0.3f * wave;        float blue   = 0.2f - 0.2f * wave;        float alpha  = 1.0f;                _particle[p].color = glm::vec4(red, green, blue, alpha);    }}  void ParticleSystem::runSpecialEffectsTest(int e, float deltaTime) {     _timer += deltaTime;           _emitter[e].gravity            = 0.0f                           + 0.05f        * sinf( _timer * 0.52f );    _emitter[e].airFriction        = (DEFAULT_PARTICLE_AIR_FRICTION + 0.5f) + 2.0f * sinf( _timer * 0.32f );    _emitter[e].jitter             = 0.05f                          + 0.05f        * sinf( _timer * 0.42f );    _emitter[e].emitterAttraction  = 0.015f                         + 0.015f       * cosf( _timer * 0.6f  );    _emitter[e].tornadoForce       = 0.0f                           + 0.03f        * sinf( _timer * 0.7f  );    _emitter[e].neighborAttraction = 0.1f                           + 0.1f         * cosf( _timer * 0.8f  );    _emitter[e].neighborRepulsion  = 0.2f                           + 0.2f         * sinf( _timer * 0.4f  );     if (_emitter[e].gravity < 0.0f) {        _emitter[e].gravity = 0.0f;    }}  void ParticleSystem::updateParticle(int p, float deltaTime) {     _particle[p].age += deltaTime;        if (_particle[p].age > _particle[p].lifespan) {        killParticle(p);    }        Emitter myEmitter = _emitter[_particle[p].emitterIndex];     // apply random jitter    _particle[p].velocity +=     glm::vec3    (        -myEmitter.jitter * ONE_HALF + myEmitter.jitter * randFloat(),         -myEmitter.jitter * ONE_HALF + myEmitter.jitter * randFloat(),         -myEmitter.jitter * ONE_HALF + myEmitter.jitter * randFloat()    ) * deltaTime;        // apply attraction to home position    glm::vec3 vectorToHome = myEmitter.position - _particle[p].position;    _particle[p].velocity += vectorToHome * myEmitter.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.neighborAttraction * deltaTime;         float distanceToNeighbor = glm::length(vectorToNeighbor);        if (distanceToNeighbor > 0.0f) {            _particle[neighbor].velocity += (vectorToNeighbor / ( 1.0f + distanceToNeighbor * distanceToNeighbor)) * myEmitter.neighborRepulsion * deltaTime;        }    }        // apply tornado force    glm::vec3 tornadoDirection = glm::cross(vectorToHome, myEmitter.up);    _particle[p].velocity += tornadoDirection * myEmitter.tornadoForce * deltaTime;     // apply air friction    float drag = 1.0 - myEmitter.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.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.bounce;        }    }        // collision with sphere    if (myEmitter.usingCollisionSphere) {        glm::vec3 vectorToSphereCenter = myEmitter.collisionSpherePosition - _particle[p].position;        float distanceToSphereCenter = glm::length(vectorToSphereCenter);        float combinedRadius = myEmitter.collisionSphereRadius + _particle[p].radius;        if (distanceToSphereCenter < combinedRadius) {                    if (distanceToSphereCenter > 0.0f){                glm::vec3 directionToSphereCenter = vectorToSphereCenter / distanceToSphereCenter;                _particle[p].position = myEmitter.collisionSpherePosition - directionToSphereCenter * combinedRadius;                        }        }    }} void ParticleSystem::setCollisionSphere(int e, glm::vec3 position, float radius) {    _emitter[e].usingCollisionSphere    = true;    _emitter[e].collisionSpherePosition = position;     _emitter[e].collisionSphereRadius   = radius;} void ParticleSystem::render() {     // render the emitters    for (unsigned int e = 0; e < _numEmitters; e++) {        if (_emitter[e].showingEmitter) {            renderEmitter(e, 0.2f);        }    };       // render the particles    for (unsigned int p = 0; p < _numParticles; p++) {        if (_particle[p].alive) {            renderParticle(p);        }    }} void ParticleSystem::renderParticle(int p) {     glColor4f(_particle[p].color.r, _particle[p].color.g, _particle[p].color.b, _particle[p].color.a );    glPushMatrix();    glTranslatef(_particle[p].position.x, _particle[p].position.y, _particle[p].position.z);    glutSolidSphere(_particle[p].radius, 6, 6);    glPopMatrix();     // render velocity lines    glColor4f( _particle[p].color.x, _particle[p].color.y, _particle[p].color.z, 0.5f);    glm::vec3 end = _particle[p].position - _particle[p].velocity * 2.0f;    glBegin(GL_LINES);    glVertex3f(_particle[p].position.x, _particle[p].position.y, _particle[p].position.z);    glVertex3f(end.x, end.y, end.z);        glEnd();}   void ParticleSystem::renderEmitter(int e, float size) {        glm::vec3 r = _emitter[e].right * size;    glm::vec3 u = _emitter[e].up    * size;    glm::vec3 f = _emitter[e].front * size;     glLineWidth(2.0f);     glColor3f(0.8f, 0.4, 0.4);    glBegin(GL_LINES);    glVertex3f(_emitter[e].position.x, _emitter[e].position.y, _emitter[e].position.z);    glVertex3f(_emitter[e].position.x + r.x, _emitter[e].position.y + r.y, _emitter[e].position.z + r.z);    glEnd();     glColor3f(0.4f, 0.8, 0.4);    glBegin(GL_LINES);    glVertex3f(_emitter[e].position.x, _emitter[e].position.y, _emitter[e].position.z);    glVertex3f(_emitter[e].position.x + u.x, _emitter[e].position.y + u.y, _emitter[e].position.z + u.z);    glEnd();     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 + f.x, _emitter[e].position.y + f.y, _emitter[e].position.z + f.z);    glEnd();}