/**
 * Pixel Pattern
 * By Raphael Rouvinov-Kats
 * */

frameRate(0);

var pattern = function(posX, posY) {
    if (!this.loadPixels) { return; }
    this.loadPixels();
    var pix=this.imageData.data;
    
    var l = 401 * 401;
    while(l--) {
        var x = l % 401;
        var y = (l-x)/401;
        
        var dx = posX - x;
        var dy = posY - y;
        var d = sqrt(dx*dx + dy*dy);
        
        // the line where the magic happens
        var diag = (x+y) % 16 < 8;
        
        var ind = (x + y * 400) << 2;
        pix[ind]   = diag ? d : 255;
        pix[ind+1] = diag ? 0 : 255;
        pix[ind+2] = diag ? 0 : 255;
    }
    
    this.updatePixels();
};

var mousePressed = function() {
    pattern(mouseX, mouseY);
};