// Robin Edwards, 2012
// Script for making friendly moving squares
// Please plagiarise at will (he'll appreciate the change from being shot at).

ArrayList <Effect> effects;
Effect [] bgrd;
char[] letters = {'a','A','b','B','c','C','d','D','e','E',
'f','F','g','G','h','H','i','I','j','J','k','K','l','L',
'm','M','n','N','o','O','p','P','q','Q','r','R','s','S',
't','T','u','U','v','V','w','W','x','X','y','Y','z','Z',
'0','1','2','3','4','5','6','7','8','9'}; // 62 long
PImage img;
int side = 125;
int x_side, y_side, init;
PVector[] dirs = { // direction vectors
  new PVector(1, 0), new PVector(-1, 0), 
  new PVector(0, 1), new PVector(0, -1)
};
int vi;            // vector randomiser
float scaler;      // tailor res for mobile and high-res devices 
PVector m, pv;

void setup() {
  size(window.innerWidth, window.innerHeight);
  //size(1000, 500);
  background(44);
  x_side = width/side;
  y_side = height/side;
  img = loadImage("rectangles_background.png");
  for(int i=0; i<x_side; i++) for(int j=0; j<y_side; j++) image(img, i*side, j*side);
  if (width < 1000) scaler = 2;
  else scaler = float(width)/1000;
  frameRate(30);
  rectMode(CENTER);
  textSize(20);
  textAlign(CENTER);
  effects = new ArrayList();
  bgrd = new Effect[5];
  for (int i=0; i<5; i++) {
    PVector p = new PVector(random(100,width-100),random(100,height-100));
    bgrd[i] = new Effect(p, false);
  }
  init = 0;
  mouseX = -100;
  mouseY = -100;
}


void draw() {
  // background
  //println(frameRate);
  for(int i=0; i<x_side; i++) for(int j=0; j<y_side; j++) image(img, i*side, j*side);
  x_side = window.innerWidth/side;
  y_side = window.innerHeight/side;
  if (frameCount%5 == 0) {
    effects.add(new Effect(new PVector(bgrd[init].p.x, bgrd[init].p.y), true));
    init++;
    init = init%5;
  }
  
  // background tiles
  for (int i=0; i<5; i++) bgrd[i].move();

  // foreground squares
  for (int i = effects.size()-1; i>=0; i--) {
    effects.get(i).move();
    if (effects.get(i).dead) effects.remove(i);
  }
  
  // mouse chaser
  m = new PVector(mouseX, mouseY);
  for(int i=0; i<effects.size(); i++){
    pv = PVector.sub(effects.get(i).p, m);
    if(pv.mag() < 75){
      pv.limit(5);
      effects.get(i).p.add(pv);
    }
  }

  for (Effect i:effects) {
    fill(i.c);
    stroke(i.c);
    rect(i.p.x, i.p.y, i.side, i.side);
    //textSize(i.side*3);
    //text(i.letter, i.p.x, i.p.y);
  }
}


class Effect {
  PVector p, v;
  int side = 0;
  int transp = 255;
  float speed;
  color c;
  boolean dead = false;
  boolean front;
  char letter;

  Effect(PVector P, boolean FRONT) {
    front = FRONT;
    //letter = letters[int(random(0,letters.length))];
    
    if (front) {
      c = color(random(0, 255), random(0, 255), random(0, 255));
      side = int(scaler * random(3, 8));
      speed = float(side)/5;
    }
    else {
  speed = 0.2;
  c = color(random(0, 255), random(0, 255), random(0, 255), 6);
  }
    p = new PVector(P.x, P.y);
    vi = int(random(4));
    v = new PVector(dirs[vi].x, dirs[vi].y);
    v.mult(speed);
  }

  void move() {
    if (front) { // main animation
      if (transp<=0 || p.x>width || p.x<0 || p.y<0 || p.y>height) dead = true;
      else {
        transp -= 1;
        c = color(red(c), green(c), blue(c), transp);
        if (random(-1, 50) < 0) changeCourse();
      }
    }
    else { // background tiles
      if (random(-1, 100) < 0) changeCourse();
      if (p.x<10 || p.x>width-10 || p.y<10 || p.y>height-10) v.mult(-1);
    }
    p.add(v);
  }

  void changeCourse() {
    if (v.y == 0) vi = int(random(2, 4)); // horizontal movers
    else vi = int(random(0, 2));         // vertical movers
    v = new PVector(dirs[vi].x, dirs[vi].y);
    v.mult(speed);
  }
}

void keyPressed(){
  if(key=='r') setup();
}

window.onresize = function(event) {
  size(window.innerWidth, window.innerHeight-3);
}