Shattering effect

[Yen]

I'm really fond of this effect. I like it a lot.

Why don't I use getimgwidth/height()?
If the image isn't loaded into memory, it returns no value. I'm setting constants to the height and width, so the effect will still display even if the image hasn't been loaded yet.

PHP Code:

function onPlayerEnters() {
  this.psize = 4; // Number of columns and rows of particles to be used (x^2 is the total number of particles)
  this.imgw = 32; // Width of the image being used
  this.imgh = 32; // Height of the image being used
  this.useimg = "block.png"; // Image to be used
  hideimgs(50,50+this.psize^2);
  showimg(50,this.useimg,x + 1.5 - (this.imgw/16) / 2, y + 1.5 - (this.imgh/16) / 2);
  InitChips();
  setTimer(.2);
}

function InitChips() {
  this.cx = new[this.psize^2];
  this.cy = new[this.psize^2];
  this.ca = new[this.psize^2];
  this.cs = new[this.psize^2];
  this.cs2 = new[this.psize^2];
  this.cr = new[this.psize^2];
  this.cm = new[this.psize^2];
  for (a = 0; a < this.psize^2; a++) {
    this.cx[a] = ((this.imgw/this.psize) * (a%this.psize)) / 16;
    this.cy[a] = (int(this.imgh/this.psize) * int(a/this.psize)) / 16;
    this.ca[a] = random(0,pi*2);
    this.cs[a] = this.cs2[a] = random(.3,.6);
    this.cr[a] = 0;
    this.cm[a] = int(random(0,2));
  }
}

function onTimeout() {
  for (b = 0; b < this.psize^2; b++) {
    if (this.cy[b] > 3.5) {
      hideimg(50+b);
      continue;
    }
    showimg(50+b,this.useimg,(player.x + 1.5 - (this.imgw/16)/2) + this.cx[b],(player.y + 1.5 - (this.imgh/16)/2) + this.cy[b]);
    changeimgpart(50+b, (this.imgw/this.psize) * (b%this.psize), int(this.imgh/this.psize) * int(b/this.psize), (this.imgw/this.psize), (this.imgh/this.psize));
    findimg(50+b).rotation = this.cr[b];
    this.cr[b] += random(pi/8,pi/12);
    this.cs2[b] -= .1;
    this.cy[b] -= this.cs2[b];
    this.cx[b] += cos(this.ca[b]) * (this.cs[b] / 3);
    if (this.cy[b] > 3.5) hideimg(50+b);
  }
  setTimer(.05);
}