java/examples/Topics/Simulate/SmokeParticleSystem/applet/SmokeParticleSystem.java

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+import processing.core.*; 
+
+import java.applet.*; 
+import java.awt.*; 
+import java.awt.image.*; 
+import java.awt.event.*; 
+import java.io.*; 
+import java.net.*; 
+import java.text.*; 
+import java.util.*; 
+import java.util.zip.*; 
+import java.util.regex.*; 
+
+public class SmokeParticleSystem extends PApplet {
+
+/**
+ * Smoke Particle System
+ * by Daniel Shiffman.  
+ * 
+ * A basic smoke effect using a particle system. 
+ * Each particle is rendered as an alpha masked image. 
+ */
+
+ParticleSystem ps;
+Random generator;
+
+public void setup() {
+
+  size(640, 200);
+  colorMode(RGB, 255, 255, 255, 100);
+
+  // Using a Java random number generator for Gaussian random numbers
+  generator = new Random();
+
+  // Create an alpha masked image to be applied as the particle's texture
+  PImage msk = loadImage("texture.gif");
+  PImage img = new PImage(msk.width,msk.height);
+  for (int i = 0; i < img.pixels.length; i++) img.pixels[i] = color(255);
+  img.mask(msk);
+  ps = new ParticleSystem(0,new Vector3D(width/2,height-20),img);
+
+  smooth();
+}
+
+public void draw() {
+  background(75);
+
+  // Calculate a "wind" force based on mouse horizontal position
+  float dx = (mouseX - width/2) / 1000.0f;
+  Vector3D wind = new Vector3D(dx,0,0);
+  wind.display(width/2,50,500);
+  ps.add_force(wind);
+  ps.run();
+  for (int i = 0; i < 2; i++) {
+    ps.addParticle();
+  }
+}
+
+
+
+
+
+
+
+
+
+
+
+// A simple Particle class, renders the particle as an image
+
+class Particle {
+  Vector3D loc;
+  Vector3D vel;
+  Vector3D acc;
+  float timer;
+  PImage img;
+
+  // One constructor
+  Particle(Vector3D a, Vector3D v, Vector3D l, PImage img_) {
+    acc = a.copy();
+    vel = v.copy();
+    loc = l.copy();
+    timer = 100.0f;
+    img = img_;
+  }
+
+  // Another constructor (the one we are using here)
+  Particle(Vector3D l,PImage img_) {
+    acc = new Vector3D(0.0f,0.0f,0.0f);
+    float x = (float) generator.nextGaussian()*0.3f;
+    float y = (float) generator.nextGaussian()*0.3f - 1.0f;
+    vel = new Vector3D(x,y,0);
+    loc = l.copy();
+    timer = 100.0f;
+    img = img_;
+  }
+
+  public void run() {
+    update();
+    render();
+  }
+  
+  // Method to apply a force vector to the Particle object
+  // Note we are ignoring "mass" here
+  public void add_force(Vector3D f) {
+    acc.add(f);
+  }  
+
+  // Method to update location
+  public void update() {
+    vel.add(acc);
+    loc.add(vel);
+    timer -= 2.5f;
+    acc.setXY(0,0);
+  }
+
+  // Method to display
+  public void render() {
+    imageMode(CORNER);
+    tint(255,timer);
+    image(img,loc.x-img.width/2,loc.y-img.height/2);
+  }
+
+  // Is the particle still useful?
+  public boolean dead() {
+    if (timer <= 0.0f) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+}
+
+
+
+
+// A class to describe a group of Particles
+// An ArrayList is used to manage the list of Particles 
+
+class ParticleSystem {
+
+  ArrayList particles;    // An arraylist for all the particles
+  Vector3D origin;        // An origin point for where particles are birthed
+  PImage img;
+  
+  ParticleSystem(int num, Vector3D v, PImage img_) {
+    particles = new ArrayList();              // Initialize the arraylist
+    origin = v.copy();                        // 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
+    }
+  }
+
+  public 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);
+      p.run();
+      if (p.dead()) {
+        particles.remove(i);
+      }
+    }
+  }
+  
+  // Method to add a force vector to all particles currently in the system
+  public void add_force(Vector3D dir) {
+    for (int i = particles.size()-1; i >= 0; i--) {
+      Particle p = (Particle) particles.get(i);
+      p.add_force(dir);
+    }
+  
+  }  
+
+  public void addParticle() {
+    particles.add(new Particle(origin,img));
+  }
+
+  public void addParticle(Particle p) {
+    particles.add(p);
+  }
+
+  // A method to test if the particle system still has particles
+  public boolean dead() {
+    if (particles.isEmpty()) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+}
+
+// Simple Vector class
+
+class Vector3D {
+  float x;
+  float y;
+  float z;
+
+  Vector3D(float x_, float y_, float z_) {
+    x = x_; 
+    y = y_; 
+    z = z_;
+  }
+
+  Vector3D(float x_, float y_) {
+    x = x_; 
+    y = y_; 
+    z = 0f;
+  }
+
+  Vector3D() {
+    x = 0f; 
+    y = 0f; 
+    z = 0f;
+  }
+
+  public void setX(float x_) {
+    x = x_;
+  }
+
+  public void setY(float y_) {
+    y = y_;
+  }
+
+  public void setZ(float z_) {
+    z = z_;
+  }
+
+  public void setXY(float x_, float y_) {
+    x = x_;
+    y = y_;
+  }
+
+  public void setXYZ(float x_, float y_, float z_) {
+    x = x_;
+    y = y_;
+    z = z_;
+  }
+
+  public void setXYZ(Vector3D v) {
+    x = v.x;
+    y = v.y;
+    z = v.z;
+  }
+  public float magnitude() {
+    return (float) Math.sqrt(x*x + y*y + z*z);
+  }
+
+  public Vector3D copy() {
+    return new Vector3D(x,y,z);
+  }
+
+  public Vector3D copy(Vector3D v) {
+    return new Vector3D(v.x, v.y,v.z);
+  }
+
+  public void add(Vector3D v) {
+    x += v.x;
+    y += v.y;
+    z += v.z;
+  }
+
+  public void sub(Vector3D v) {
+    x -= v.x;
+    y -= v.y;
+    z -= v.z;
+  }
+
+  public void mult(float n) {
+    x *= n;
+    y *= n;
+    z *= n;
+  }
+
+  public void div(float n) {
+    x /= n;
+    y /= n;
+    z /= n;
+  }
+
+  /* float dot(Vector3D v) {
+   //implement DOT product
+   }*/
+
+  /* Vector3D cross(Vector3D v) {
+   //implement CROSS product
+   }*/
+
+  public void normalize() {
+    float m = magnitude();
+    if (m > 0) {
+      div(m);
+    }
+  }
+
+  public void limit(float max) {
+    if (magnitude() > max) {
+      normalize();
+      mult(max);
+    }
+  }
+
+  public float heading2D() {
+    float angle = (float) Math.atan2(-y, x);
+    return -1*angle;
+  }
+
+  public Vector3D add(Vector3D v1, Vector3D v2) {
+    Vector3D v = new Vector3D(v1.x + v2.x,v1.y + v2.y, v1.z + v2.z);
+    return v;
+  }
+
+  public Vector3D sub(Vector3D v1, Vector3D v2) {
+    Vector3D v = new Vector3D(v1.x - v2.x,v1.y - v2.y,v1.z - v2.z);
+    return v;
+  }
+
+  public Vector3D div(Vector3D v1, float n) {
+    Vector3D v = new Vector3D(v1.x/n,v1.y/n,v1.z/n);
+    return v;
+  }
+
+  public Vector3D mult(Vector3D v1, float n) {
+    Vector3D v = new Vector3D(v1.x*n,v1.y*n,v1.z*n);
+    return v;
+  }
+
+  public float distance (Vector3D v1, Vector3D v2) {
+    float dx = v1.x - v2.x;
+    float dy = v1.y - v2.y;
+    float dz = v1.z - v2.z;
+    return (float) Math.sqrt(dx*dx + dy*dy + dz*dz);
+  }
+
+  public void display(float x, float y, float scayl) {
+    pushMatrix();
+    float arrowsize = 4;
+    // Translate to location to render vector
+    translate(x,y);
+    stroke(255);
+    // Call vector heading function to get direction (note that pointing up is a heading of 0) and rotate
+    rotate(heading2D());
+    // Calculate length of vector & scale it to be bigger or smaller if necessary
+    float len = magnitude()*scayl;
+    // Draw three lines to make an arrow (draw pointing up since we've rotate to the proper direction)
+    line(0,0,len,0);
+    line(len,0,len-arrowsize,+arrowsize/2);
+    line(len,0,len-arrowsize,-arrowsize/2);
+    popMatrix();
+  } 
+
+}
+
+
+  static public void main(String args[]) {
+    PApplet.main(new String[] { "SmokeParticleSystem" });
+  }
+}