fixing up smoke particle system

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

@@ -10,8 +10,8 @@ class Particle {
 
   Particle(PVector l,PImage img_) {
     acc = new PVector(0,0);
-    float vx = (float) generator.nextGaussian()*0.3;
-    float vy = (float) generator.nextGaussian()*0.3 - 1.0;
+    float vx = randomGaussian()*0.3;
+    float vy = randomGaussian()*0.3 - 1.0;
     vel = new PVector(vx,vy);
     loc = l.get();
     lifespan = 100.0;
@@ -33,8 +33,8 @@ class Particle {
   void update() {
     vel.add(acc);
     loc.add(vel);
-    acc.mult(0); // clear Acceleration
     lifespan -= 2.5;
+    acc.mult(0); // clear Acceleration
   }
 
   // Method to display
@@ -42,10 +42,14 @@ class Particle {
     imageMode(CENTER);
     tint(255,lifespan);
     image(img,loc.x,loc.y);
+    // Drawing a circle instead
+    // fill(255,lifespan);
+    // noStroke();
+    // ellipse(loc.x,loc.y,img.width,img.height);
   }
 
   // Is the particle still useful?
-  boolean dead() {
+  boolean isDead() {
     if (lifespan <= 0.0) {
       return true;
     } else {
@@ -54,6 +58,3 @@ class Particle {
   }
 }
 
-
-
-

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

@@ -4,25 +4,24 @@
 class ParticleSystem {
 
   ArrayList<Particle> particles;    // An arraylist for all the particles
-  PVector origin;        // An origin point for where particles are birthed
+  PVector origin;                   // An origin point for where particles are birthed
   PImage img;
   
   ParticleSystem(int num, PVector v, PImage img_) {
     particles = new ArrayList<Particle>();              // Initialize the arraylist
-    origin = v.get();                        // Store the origin point
+    origin = v.get();                                   // Store the origin point
     img = img_;
     for (int i = 0; i < num; i++) {
-      particles.add(new Particle(origin, img));    // Add "num" amount of particles to the arraylist
+      particles.add(new Particle(origin, img));         // Add "num" amount of particles to the arraylist
     }
   }
 
   void run() {
-    Iterator<Particle> it = particles.iterator();
-    while (it.hasNext()) {
-      Particle p = it.next();
+    for (int i = particles.size()-1; i >= 0; i--) {
+      Particle p = particles.get(i);
       p.run();
-      if (p.dead()) {
-        it.remove();
+      if (p.isDead()) {
+        particles.remove(i);
       }
     }
   }
@@ -40,19 +39,6 @@ class ParticleSystem {
     particles.add(new Particle(origin,img));
   }
 
-  void addParticle(Particle p) {
-    particles.add(p);
-  }
-
-  // A method to test if the particle system still has particles
-  boolean dead() {
-    if (particles.isEmpty()) {
-      return true;
-    } else {
-      return false;
-    }
-  }
-
 }
 
 

java/examples/Topics/Simulate/SmokeParticleSystem/SmokeParticleSystem.pde

@@ -11,14 +11,11 @@
 /* @pjs preload="texture.png"; */
 
 ParticleSystem ps;
-Random generator;
 
 void setup() {
   size(640,360);
-  generator = new Random();
   PImage img = loadImage("texture.png");
   ps = new ParticleSystem(0,new PVector(width/2,height-60),img);
-  smooth();
 }
 
 void draw() {