DotMatrix dots;
int i = 0;
int j = 0;
int span = 50;
int variant = 0;
int generation = 0;
int density = 1;
float emitter_x = 0.5;
float emitter_y = 0.5;
float ageing = 0.005;
boolean debug = false;

class Dot {
  
  PVector pos;
  PVector velo;
  PVector emitter;
  float lifetime = 1.0;
  float ageing;
  int dotSize;
  int variant;
  color c;
  
  Dot (PVector pos, PVector velo, PVector emitter, int initialSize, float ageing, int variant){
    this.pos = pos;
    this.velo = velo;
    this.emitter = new PVector(emitter.x, emitter.y);
    this.dotSize = initialSize;
    this.ageing = ageing;
    this.variant = variant;
    c = color(random(255), random(255), random(255));
  }
  
  void drawDot(){
    fill(c , lifetime*255);
    switch (variant){
      case 0:
      ellipse(pos.x*(emitter.x*lifetime), pos.y*(emitter.y*lifetime), dotSize*lifetime, dotSize*lifetime);  
      break;
      case 1:
      ellipse(pos.x*(emitter.x*lifetime), pos.y*(emitter.y/lifetime), dotSize*lifetime, dotSize*lifetime);  
      break;
      case 2:
      ellipse(pos.x*(emitter.x/lifetime), pos.y*(emitter.y*lifetime), dotSize*lifetime, dotSize*lifetime);  
      break;
      default:
      ellipse(pos.x*(emitter.x/lifetime), pos.y*(emitter.y/lifetime), dotSize*lifetime, dotSize*lifetime);  
      break;
    }
    lifetime-=ageing;
  }
  
  boolean isAlive(){
    return lifetime > 0;
  }
    
}

class DotMatrix {
  
  Dot [][] dots = new Dot[10][10];
  int x;
  int y;
  
  DotMatrix(){
    for (int i = 0; i < dots.length; i++){
      for (int j = 0; j < dots[i].length; j++){
        //dots[i][j]= new Dot(new PVector(i*span,j*span), new PVector(0,0),new PVector(emitter_x,emitter_y), span, ageing, variant);  
      }
    }
  }
  
  void render(){
    for (int i = 0; i < dots.length; i++){
      for (int j = 0; j < dots[i].length; j++){
        if (dots[i][j]!=null){
          Dot d = dots[i][j];
          d.drawDot();
          if (!d.isAlive()){
            dots[i][j]=null;           
          }
        }        
      }
    }
    
    if (generation++ % density == 0){
      int rand_x = int(random(dots.length));
      int rand_y = int(random(dots.length));
      dots[rand_x][rand_y]= new Dot(new PVector(rand_x*span,rand_y*span), new PVector(0,0), new PVector(emitter_x,emitter_y), span, ageing, variant);
    }
  }
  
}

void setup() {
  
  dots = new DotMatrix();
  size(1000, 600, P2D);
  noStroke();
  fill(204, 204);
  background(0);
}

float rotator = 0.0;

void draw() {
  
  translate(width/3,height/2);
  rotate(rotator);
  rotator += 0.01;
  background(0);
  dots.render();
  span+= random(-3, 4);
  if (span < 5){
    span=5;
  }else if (span > 80){
    span=80;
  }
   
}

void mouseClicked() {
  span = int(random(5, 80));
  emitter_x = random(0.1, 3.0);
  emitter_y = random(0.1, 3.0);
  variant = int(random(0, 4));
  ageing = random(0.0005, 0.01);
  density = int(random(1,5));
  if (debug){
    println ("emitter_x:"+emitter_x+" emitter_y:"+emitter_y +" variant:"+variant);
  }
  
}