cssAudio - Activefile-genericCSS - ActiveGeneric - ActiveHTML - ActiveImage - ActiveJS - ActiveSVG - ActiveText - Activefile-genericVideo - ActiveLovehtmlicon-new-collectionicon-personicon-teamlog-outoctocatpop-outspinnerstartv

Untitled

A Pen By Captain Anonymous

Pen Settings

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. If you link to another Pen, it will include the CSS from that Pen. If the preprocessor matches, it will attempt to combine them before processing.

Quick-add: + add another resource

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

Quick-add: + add another resource

Code Indentation

     

Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

            
              <body onload="main()">
<canvas id="pal" width="500" height="30"></canvas><br/>
<canvas id="img" width="500" height="500"></canvas><br/>
<div id="tilesLeft">.</div>
</body>

            
          
!
            
              body   { background-color:#444444; font-family:monospace; }
canvas { background-color:#ffffff; border:solid 4px black; }

            
          
!
            
              function main() {
  
  function clamp(n) {
    n *= 255;
    if( n <   0 ) return   0;
    if( n > 255 ) return 255;
    return Math.floor(n);
}

function toPix(c) {
    return {r:clamp(c.r), g:clamp(c.g), b:clamp(c.b)};
}

function drawPal(canvas) {
    var ctx = canvas.getContext('2d');
    var dat = ctx.getImageData(0, 0, canvas.width, canvas.height);
    
    for(var x = 0; x < canvas.width; x++) {
        var t = x/canvas.width;
        var c = getPal(t);
        var p = toPix(c);
        
        for(var y = 0; y < canvas.height; y++) {
            var offset = 4*(y*canvas.width + x);
            dat.data[offset + 0] = p.r;
            dat.data[offset + 1] = p.g;
            dat.data[offset + 2] = p.b;
            dat.data[offset + 3] = 255;            
        }
    }
    
    ctx.putImageData(dat, 0, 0);
}

function computeOrbit(c) {
    
    orbit[0].re = 0;
    orbit[0].im = 0;
    
    orbit.escaped = false;
    orbit.numPoints = 1;
    
    var er = escapeRadius*escapeRadius;
    
    for(var i = 1; i < maxIters; i++) {
        var zp = orbit[i - 1];
        var zn = orbit[i];
        
        //z[i] = z[i - 1]^2 + c
        zn.re = zp.re*zp.re - zp.im*zp.im + c.re;
        zn.im = zp.re*zp.im + zp.im*zp.re + c.im;
        
        orbit.numPoints++;
        
        var mr = zn.re*zn.re + zn.im*zn.im;
        
        if( mr > er ) {
            orbit.escaped = true;
            break;
        }
    }
}

function mag(z) {
    var s = z.re*z.re + z.im*z.im;
    
    if( s != 0 ) {
        s = Math.sqrt(s);
    }
    
    return s;
}

//sets global var avgSum
function triangleInEq(orbit, numPoints, c) {

    avgSum.s1 = 0;
    avgSum.s2 = 0;

    if( numPoints < 3 ) {
        return 0;
    }
    
    var mc = mag(c);
    
    for(var i = 2; i < numPoints; i++) {
        var zp = orbit[i - 1];
        var zc = orbit[i];

        //tc = zp^2 
        tc.re = zp.re*zp.re - zp.im*zp.im;
        tc.im = zp.re*zp.im + zp.im*zp.re;

        var mp = mag(tc);
        
        var m = Math.abs( mp - mc);
        var M =           mp + mc;
        
        avgSum.s1 = avgSum.s2;
        avgSum.s2 += (mag(zc) - m)/(M - m);
    }

    avgSum.s1 /= numPoints - 3; 
    avgSum.s2 /= numPoints - 2; 
}

//pre: orbit.escaped && orbit.numPoints >= 2
function computeSmooth(orbit) {
    var zc = orbit[orbit.numPoints - 1];
    var mc = mag(zc);
    
    return 1 + 1/Math.log(2)*Math.log( Math.log(escapeRadius)/Math.log(mc) );
}

function genNextTile() {
    if( tiles.length === 0) {
        return;
    }
    
    var tile = tiles.pop();    
    var dat = ctx.getImageData(tile.x, tile.y, tile.w, tile.h);
    
    for(var j = 0; j < tile.h; j++) {
        for(var i = 0; i < tile.w; i++) {
            
            var offset = 4*(j*tile.w + i);
            var p = {r:0, g:0, b:0};
            
            for(var sj = 0; sj < superSamples; sj++) {
                for(var si = 0; si < superSamples; si++) {
                    var x = tile.x + i + si/superSamples;
                    var y = tile.y + j + sj/superSamples;
                    var c = {
                        re:x/img.width *(maxRe - minRe) + minRe,
                        im:y/img.height*(maxIm - minIm) + minIm};
                    
                    computeOrbit(c);
                    
                    if( orbit.escaped ) {
                         
                        var sm = computeSmooth(orbit);

                        triangleInEq(
                            orbit, 
                            orbit.numPoints, 
                            c);

                        var t = avgSum.s1*(1 - sm) + avgSum.s2*(sm);
                        var m = getPal(t);
                        
                        p.r += m.r; 
                        p.g += m.g; 
                        p.b += m.b;
                    }
                    
                    else {
                        p.r += inColor.r; 
                        p.g += inColor.g; 
                        p.b += inColor.b;
                    }                    
                }
            }
            
            p.r /= samplesPerPixel;
            p.g /= samplesPerPixel;
            p.b /= samplesPerPixel;
            
            var rgb = toPix(p);
            
            dat.data[offset + 0] = rgb.r;
            dat.data[offset + 1] = rgb.g;
            dat.data[offset + 2] = rgb.b;
            dat.data[offset + 3] = 255;
        }
    }
       
    ctx.putImageData(dat, tile.x, tile.y);
    statusDiv.innerHTML = tiles.length + ' tile(s)';    
    setTimeout(genNextTile, 1);
}

function getPal(t) {
    t = 1 - t;
    return {
        r:Math.pow(t, 3.0), 
        g:Math.pow(t, 1.0), 
        b:Math.pow(t, 0.2)
        };
}


var avgSum = {s1:0, s2:0};
var inColor = {r:1, g:1, b:1};
var superSamples = 3;
var samplesPerPixel = superSamples*superSamples;
var center = {
    re:-0.740, 
    im:0.208
};

var radius = 0.01; //0.005;
var tc = {re:0,im:0};
var img = document.getElementById('img');
var aspectRatio = img.height/img.width;
var minRe = center.re - radius;
var maxRe = center.re + radius;
var minIm = center.im - radius*aspectRatio;
var maxIm = center.im + radius*aspectRatio;
var escapeRadius = 1000;
var maxIters = 1000;
var statusDiv = document.getElementById('tilesLeft');
var ctx = img.getContext('2d');
var tileSize = 20;

drawPal(document.getElementById('pal'));

//pre allocated orbit to avoid doing it over and over
var orbit = [];

for(var i = 0; i < maxIters; i++) {
    orbit[i] = {re:0,im:0};
}

//only draw a tile at a time on the main event queue
//so that the browser does not complain
//about the script taking too long
var tiles = [];

for(var y = 0; y < img.height; y += tileSize) {
    for(var x = 0; x < img.width; x += tileSize) {
        tiles.push({
            x:x, 
            y:y, 
            w:Math.min(img.width  - x, tileSize), 
            h:Math.min(img.height - y, tileSize)});
    }
}

genNextTile();  
  
}
            
          
!
999px
Loading ..................

Console