changes to simulate examples

java/examples/Topics/Simulate/MultipleParticleSystems/MultipleParticleSystems.pde

@@ -9,32 +9,31 @@
  * with Particles and CrazyParticles (a subclass of Particle)
  * Note use of Inheritance and Polymorphism here. 
  */
- 
-ArrayList psystems;
+
+ArrayList<ParticleSystem> systems;
 
 void setup() {
   size(640, 360);
-  colorMode(RGB, 255, 255, 255, 100);
-  psystems = new ArrayList();
+  systems = new ArrayList<ParticleSystem>();
+  smooth();
 }
 
 void draw() {
   background(0);
-
-  // Cycle through all particle systems, run them and delete old ones
-  for (int i = psystems.size()-1; i >= 0; i--) {
-    ParticleSystem psys = (ParticleSystem) psystems.get(i);
-    psys.run();
-    if (psys.dead()) {
-      psystems.remove(i);
-    }
+  for (ParticleSystem ps: systems) {
+    ps.run();
+    ps.addParticle();
   }
 
+  if (systems.isEmpty()) {
+    fill(255);
+    textAlign(CENTER);
+    text("click mouse to add particle systems", width/2, height/2);
+  }
 }
 
-// When the mouse is pressed, add a new particle system
 void mousePressed() {
-  psystems.add(new ParticleSystem(int(random(5,25)),new PVector(mouseX,mouseY)));
+  systems.add(new ParticleSystem(1, new PVector(mouseX, mouseY)));
 }
 
 
@@ -46,4 +45,3 @@ void mousePressed() {
 
 
 
-

java/examples/Topics/Simulate/MultipleParticleSystems/Particle.pde

@@ -1,57 +1,44 @@
 // A simple Particle class
 
 class Particle {
-  PVector loc;
-  PVector vel;
-  PVector acc;
-  float r;
-  float timer;
+  PVector location;
+  PVector velocity;
+  PVector acceleration;
+  float lifespan;
 
-  // One constructor
-  Particle(PVector a, PVector v, PVector l, float r_) {
-    acc = a.get();
-    vel = v.get();
-    loc = l.get();
-    r = r_;
-    timer = 100.0;
-  }
-  
-  // Another constructor (the one we are using here)
   Particle(PVector l) {
-    acc = new PVector(0,0.05,0);
-    vel = new PVector(random(-1,1),random(-2,0),0);
-    loc = l.get();
-    r = 10.0;
-    timer = 100.0;
+    acceleration = new PVector(0,0.05);
+    velocity = new PVector(random(-1,1),random(-2,0));
+    location = l.get();
+    lifespan = 255.0;
   }
 
-
   void run() {
     update();
-    render();
+    display();
   }
 
   // Method to update location
   void update() {
-    vel.add(acc);
-    loc.add(vel);
-    timer -= 1.0;
+    velocity.add(acceleration);
+    location.add(velocity);
+    lifespan -= 2.0;
   }
 
   // Method to display
-  void render() {
-    ellipseMode(CENTER);
-    stroke(255,timer);
-    fill(100,timer);
-    ellipse(loc.x,loc.y,r,r);
+  void display() {
+    stroke(255,lifespan);
+    fill(255,lifespan);
+    ellipse(location.x,location.y,8,8);
   }
   
   // Is the particle still useful?
-  boolean dead() {
-    if (timer <= 0.0) {
+  boolean isDead() {
+    if (lifespan < 0.0) {
       return true;
     } else {
       return false;
     }
   }
 }
+

java/examples/Topics/Simulate/MultipleParticleSystems/ParticleSystem.pde

@@ -2,29 +2,25 @@
 
 class ParticleSystem {
 
-  ArrayList particles;    // An arraylist for all the particles
-  PVector origin;        // An origin point for where particles are birthed
+  ArrayList<Particle> particles;    // An arraylist for all the particles
+  PVector origin;                   // An origin point for where particles are birthed
 
   ParticleSystem(int num, PVector v) {
-    particles = new ArrayList();              // Initialize the arraylist
+    particles = new ArrayList<Particle>();   // Initialize the arraylist
     origin = v.get();                        // Store the origin point
     for (int i = 0; i < num; i++) {
-      // We have a 50% chance of adding each kind of particle
-      if (random(1) < 0.5) {
-        particles.add(new CrazyParticle(origin)); 
-      } else {
-        particles.add(new Particle(origin)); 
-      }
+      particles.add(new Particle(origin));    // Add "num" amount of particles to the arraylist
     }
   }
 
   void run() {
-    // Cycle through the ArrayList backwards b/c we are deleting
-    for (int i = particles.size()-1; i >= 0; i--) {
-      Particle p = (Particle) particles.get(i);
+    // Cycle through the ArrayList using Iterator we are deleting
+    Iterator<Particle> it = particles.iterator();
+    while (it.hasNext()) {
+      Particle p = it.next();
       p.run();
-      if (p.dead()) {
-        particles.remove(i);
+      if (p.isDead()) {
+        it.remove();
       }
     }
   }
@@ -41,11 +37,9 @@ class ParticleSystem {
   boolean dead() {
     if (particles.isEmpty()) {
       return true;
-    } 
-    else {
+    } else {
       return false;
     }
   }
 
 }
-