//
// particle.cpp
// interface
//
// Created by Seiji Emery on 9/4/12.
// Copyright (c) 2012 __MyCompanyName__. All rights reserved.
//
#include "particle.h"
#define NUM_ELEMENTS 4
glm::vec3 color0(1,0,0); // Motionless particle
glm::vec3 color1(0,1,0); // Spring force
glm::vec3 color2(0,0,1);
glm::vec3 color3(0,1,1);
float radii[NUM_ELEMENTS] = {0.3, 0.5, 0.2, 0.4};
ParticleSystem::ParticleSystem(int num,
glm::vec3 box,
int wrap,
float noiselevel,
float setscale,
float setgravity) {
// Create and initialize particles
int i, element;
bounds = box;
count = num;
wrapBounds = false;
noise = noiselevel;
gravity = setgravity;
scale = setscale;
particles = new Particle[count];
for (i = 0; i < count; i++) {
particles[i].position.x = randFloat()*box.x;
particles[i].position.y = randFloat()*box.y;
particles[i].position.z = randFloat()*box.z;
// Constrain to a small box in center
//particles[i].position.x = randFloat()+box.x/2.0;
//particles[i].position.y = randFloat()+box.y/2.0;
//particles[i].position.z = randFloat()+box.z/2.0;
particles[i].velocity.x = 0;
particles[i].velocity.y = 0;
particles[i].velocity.z = 0;
particles[i].parent = 0;
particles[i].link *= 0;
element = 1; //rand()%NUM_ELEMENTS;
particles[i].element = element;
if (element == 0) particles[i].color = color0;
else if (element == 1) particles[i].color = color1;
else if (element == 2) particles[i].color = color2;
else if (element == 3) particles[i].color = color3;
particles[i].radius = 0.10; //radii[element]*scale;
particles[i].isColliding = false;
}
}
bool ParticleSystem::updateHand(glm::vec3 pos, glm::vec3 vel, float radius) {
handPos = pos;
handVel = vel;
handRadius = radius;
return handIsColliding;
}
void ParticleSystem::resetHand() {
handActive = false;
handIsColliding = false;
handPos = glm::vec3(0,0,0);
handVel = glm::vec3(0,0,0);
handRadius = 0;
}
void ParticleSystem::render() {
for (unsigned int i = 0; i < count; ++i) {
glPushMatrix();
glTranslatef(particles[i].position.x, particles[i].position.y, particles[i].position.z);
if (particles[i].numSprung == 0) glColor3f(1,1,1);
else if (particles[i].numSprung == 1) glColor3f(0,1,0);
else if (particles[i].numSprung == 2) glColor3f(1,1,0);
else if (particles[i].numSprung >= 3) glColor3f(1,0,0);
glutSolidSphere(particles[i].radius, 15, 15);
glPopMatrix();
}
}
void ParticleSystem::link(int child, int parent) {
particles[child].parent = parent;
particles[child].velocity *= 0.5;
particles[parent].velocity += particles[child].velocity;
particles[child].velocity *= 0.0;
particles[child].color = glm::vec3(1,1,0);
particles[child].link = particles[parent].position - particles[child].position;
}
void ParticleSystem::simulate (float deltaTime) {
int i, j;
for (i = 0; i < count; ++i) {
if (particles[i].element != 0) {
if (particles[i].parent == 0) {
// Move particles
particles[i].position += particles[i].velocity * deltaTime;
// Add gravity
particles[i].velocity.y -= gravity*deltaTime;
// Drag: decay velocity
const float CONSTANT_DAMPING = 0.1;
particles[i].velocity *= (1.f - CONSTANT_DAMPING*deltaTime);
// Add velocity from field
//Field::addTo(particles[i].velocity);
//particles[i].velocity += Field::valueAt(particles[i].position);
// Add noise
const float RAND_VEL = 0.05;
if (noise) {
if (1) {
particles[i].velocity += glm::vec3((randFloat() - 0.5)*RAND_VEL,
(randFloat() - 0.5)*RAND_VEL,
(randFloat() - 0.5)*RAND_VEL);
}
if (randFloat() < noise*deltaTime) {
particles[i].velocity += glm::vec3((randFloat() - 0.5)*RAND_VEL*100,
(randFloat() - 0.5)*RAND_VEL*100,
(randFloat() - 0.5)*RAND_VEL*100);
}
}
} else {
particles[i].position = particles[particles[i].parent].position + particles[i].link;
}
// Check for collision with manipulator hand
particles[i].isColliding = (glm::vec3(particles[i].position - handPos).length() <
(radius + handRadius));
// Check for collision with other balls
float separation;
const float HARD_SPHERE_FORCE = 100.0;
const float SPRING_FORCE = 10.0;
const float SPRING_DAMPING = 0.5;
float spring_length = 0.5; //2*radii[1];
float spring_range = spring_length * 1.2;
float contact;
particles[i].isColliding = false;
particles[i].numSprung = 0;
for (j = 0; j < count; j++) {
if ((j != i) &&
(!particles[i].parent)) {
separation = glm::distance(particles[i].position, particles[j].position);
contact = particles[i].radius + particles[j].radius;
// Hard Sphere Scattering
if (separation < contact) {
particles[i].velocity += glm::normalize(particles[i].position - particles[j].position)*deltaTime*HARD_SPHERE_FORCE*(contact - separation);
particles[i].isColliding = true;
}
// Spring Action
if ((particles[i].element == 1) && (separation < spring_range)) {
particles[i].velocity += glm::normalize(particles[i].position - particles[j].position)*deltaTime*SPRING_FORCE*(spring_length - separation);
particles[i].velocity *= (1.f - SPRING_DAMPING*deltaTime);
particles[i].numSprung++;
}
// Link!
if ((particles[i].parent == 0) &&
(particles[j].parent != i) &&
(separation > 0.9*(particles[j].radius + particles[i].radius)) &&
(separation < 1.0*(particles[j].radius + particles[i].radius)) ) {
// Link i to j!!
//link(i, j);
}
}
}
if (!particles[i].parent) {
if (wrapBounds) {
// wrap around bounds
if (particles[i].position.x > bounds.x)
particles[i].position.x -= bounds.x;
else if (particles[i].position.x < 0.0f)
particles[i].position.x += bounds.x;
if (particles[i].position.y > bounds.y)
particles[i].position.y -= bounds.y;
else if (particles[i].position.y < 0.0f)
particles[i].position.y += bounds.y;
if (particles[i].position.z > bounds.z)
particles[i].position.z -= bounds.z;
else if (particles[i].position.z < 0.0f)
particles[i].position.z += bounds.z;
} else {
// Bounce at bounds
if (particles[i].position.x > bounds.x
|| particles[i].position.x < 0.f) {
if (particles[i].position.x > bounds.x) particles[i].position.x = bounds.x;
else particles[i].position.x = 0.f;
particles[i].velocity.x *= -1;
}
if (particles[i].position.y > bounds.y
|| particles[i].position.y < 0.f) {
if (particles[i].position.y > bounds.y) particles[i].position.y = bounds.y;
else particles[i].position.y = 0.f;
particles[i].velocity.y *= -1;
}
if (particles[i].position.z > bounds.z
|| particles[i].position.z < 0.f) {
if (particles[i].position.z > bounds.z) particles[i].position.z = bounds.z;
else particles[i].position.z = 0.f;
particles[i].velocity.z *= -1;
}
}
}
}
}
}