/**
 * Rainbow road
 * by Raphael Rouvinov-Kats
 * */
frameRate(0);
var draw = function() {
    if (!this.loadPixels) { return; }
    this.loadPixels();
    var pix=this.imageData.data;
    
    var l = 201 * 201;
    while(l--) {
        // coords
        var x = l % 201;
        var y = (l-x)/201;
        
        // dist from center
        var x2 = 200 - x;
        var y2 = 200 - y;
        var d = sqrt(x2*x2+y2*y2);
        
        // 'time'
        var t = (d * frameCount * frameCount)%360;
        
        // http://jsperf.com/native-sin-vs-approx-fast-sin
        // this is var s = 255 * sin(t)
        var s = 255* (0.02222222*t - 0.00012345679 * t * t);
        
        var xr = 400 - x; // x-right
        var yb = 400 - y; // y-bottom
        
        var willShowR = frameCount % 3 === 0;
        var willShowG = frameCount % 4 === 0;
        var willShowB = frameCount % 5 === 0;
        
        // top-left
        if(willShowR) {
            pix[(25*y<<6)+(x<<2)] += s;
            pix[(25*y<<6)+(xr<<2)] += s;
            pix[(25*yb<<6)+(x<<2)] += s;
            pix[(25*yb<<6)+(xr<<2)] += s;
            pix[(25*y<<6)+(x<<2)] /= 2;
            pix[(25*y<<6)+(xr<<2)] /= 2;
            pix[(25*yb<<6)+(x<<2)] /= 2;
            pix[(25*yb<<6)+(xr<<2)] /= 2;
        }
        if(willShowG) {
            pix[(25*y<<6)+(x<<2)+1] += s;
            pix[(25*y<<6)+(xr<<2)+1] += s;
            pix[(25*yb<<6)+(x<<2)+1] += s;
            pix[(25*yb<<6)+(xr<<2)+1] += s;
            pix[(25*y<<6)+(x<<2)+1] /= 2;
            pix[(25*y<<6)+(xr<<2)+1] /= 2;
            pix[(25*yb<<6)+(x<<2)+1] /= 2;
            pix[(25*yb<<6)+(xr<<2)+1] /= 2;
        }
        if(willShowB) {
            pix[(25*y<<6)+(x<<2)+2] += s;
            pix[(25*y<<6)+(xr<<2)+2] += s;
            pix[(25*yb<<6)+(x<<2)+2] += s;
            pix[(25*yb<<6)+(xr<<2)+2] += s;
            pix[(25*y<<6)+(x<<2)+2] /= 2;
            pix[(25*y<<6)+(xr<<2)+2] /= 2;
            pix[(25*yb<<6)+(x<<2)+2] /= 2;
            pix[(25*yb<<6)+(xr<<2)+2] /= 2;
        }
    }
    
    debug(this.__frameRate);
    this.updatePixels();
};