/** 
a small mousewheel tutorial by <a href="http://www.local-guru.net/blog">guru</a>
*/

void setup() {
  size(300,300);
  smooth();
  addMouseWheelListener(new java.awt.event.MouseWheelListener() { 
    public void mouseWheelMoved(java.awt.event.MouseWheelEvent evt) { 
      mouseWheel(evt.getWheelRotation());
  }}); 
}

float s = 10;

void mouseWheel(int delta) {
  float t = s + delta * 2;
  if (t> 2 && t < 300 ) {
    s = t;
  }
}

void draw() {
  background(255);
  stroke(0);
  translate( width/2, height/2);  
  int cnt = int( width/s);
  for( int x = -cnt; x < cnt; x++) {
    for( int y = -cnt; y < cnt; y++ ) {
      rect(x * s - s/2, y * s - s/2, s, s );
    }
  }
  
  
}