/**
 * definition
 * by Raphael Rouvinov-Kats
 * */

// http://stackoverflow.com
// /questions/3959211/fast-factorial-function-in-javascript
var sFact = function(num) {
    var rval=1;
    for (var i = 2; i <= num; i++) {
        rval = rval * i;
    }
    return rval;
};

mouseX=200;
mouseY=200;
frameRate(0);
var draw = function() {
    if (!this.loadPixels) { return; }
    this.loadPixels();
    var pix=this.imageData.data;
    
    var fact = sFact;
    
    var l = 201 * 201;
    while(l--) {
        // coords
        var x = l % 201;
        var y = (l-x)/201;
        
        // dist from center
        var x2 = fact((mouseX-x)/5);
        var y2 = fact((mouseY-y)/5);
        var d = sqrt(x2*x2+y2*y2);
        
        // 'time'
        var t = (d * 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 = true;
        var willShowB = true;
        
        // 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;
        }
        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;
        }
        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;
        }
    }
    
    this.updatePixels();
    
    if(random(0, 1) < 0.125) {
        filter(THRESHOLD);
    }
    else if(random(0, 1) < 0.25) {
        filter(GRAY);
    }
    else if(random(0, 1) < 0.375) {
        
    }
    else if(random(0, 1) < 0.5) {
        filter(POSTERIZE, 5);
    }
    else if(random(0, 1) < 0.675) {
        filter(BLUR);
    }
    else if(random(0, 1) < 0.75) {
        filter(OPAQUE);
    }
    else if(random(0, 1) < 0.875) {
        filter(ERODE);
    }
    else {
        filter(DILATE);
    }
};