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HTML

              
                
              
            
!

CSS

              
                head, body{
  width:100%;
  height:100%;
  overflow: hidden;
  top:0;
  left:0;
  margin:0;
  padding:0;
  background-color: #000000;
}
canvas{
  position:absolute;
  margin: auto;
  top: 0; left: 0; bottom: 0; right: 0;
}
              
            
!

JS

              
                /*
 * A speed-improved perlin and simplex noise algorithms for 2D.
 *
 * Based on example code by Stefan Gustavson (stegu@itn.liu.se).
 * Optimisations by Peter Eastman (peastman@drizzle.stanford.edu).
 * Better rank ordering method by Stefan Gustavson in 2012.
 * Converted to Javascript by Joseph Gentle.
 *
 * Version 2012-03-09
 *
 * This code was placed in the public domain by its original author,
 * Stefan Gustavson. You may use it as you see fit, but
 * attribution is appreciated.
 *
 */


var simplex = function( module )
{

    function Grad(x, y, z) {
        this.x = x; this.y = y; this.z = z;
    }

    Grad.prototype.dot2 = function(x, y) {
        return this.x*x + this.y*y;
    };

    Grad.prototype.dot3 = function(x, y, z) {
        return this.x*x + this.y*y + this.z*z;
    };

    var grad3 = [new Grad(1,1,0),new Grad(-1,1,0),new Grad(1,-1,0),new Grad(-1,-1,0),
        new Grad(1,0,1),new Grad(-1,0,1),new Grad(1,0,-1),new Grad(-1,0,-1),
        new Grad(0,1,1),new Grad(0,-1,1),new Grad(0,1,-1),new Grad(0,-1,-1)];

    var p = [151,160,137,91,90,15, 131, 13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23, 190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33, 88, 237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166, 77, 146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244, 102, 143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196, 135, 130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123, 5, 202, 38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42, 223, 183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9, 129, 22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228, 251, 34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107, 49, 192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254, 138, 236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180];

    // To remove the need for index wrapping, double the permutation table length
    var perm = new Array(512);
    var gradP = new Array(512);

    // This isn't a very good seeding function, but it works ok. It supports 2^16
    // different seed values. Write something better if you need more seeds.
    module.seed = function(seed) {
        if(seed > 0 && seed < 1) {
            // Scale the seed out
            seed *= 65536;
        }

        seed = Math.floor(seed);
        if(seed < 256) {
            seed |= seed << 8;
        }

        for(var i = 0; i < 256; i++) {
            var v;
            if (i & 1) {
                v = p[i] ^ (seed & 255);
            } else {
                v = p[i] ^ ((seed>>8) & 255);
            }

            perm[i] = perm[i + 256] = v;
            gradP[i] = gradP[i + 256] = grad3[v % 12];
        }
    };

    module.seed(0);

    /*
     for(var i=0; i<256; i++) {
     perm[i] = perm[i + 256] = p[i];
     gradP[i] = gradP[i + 256] = grad3[perm[i] % 12];
     }*/

    // Skewing and unskewing factors for 2, 3, and 4 dimensions
    var F2 = 0.5*(Math.sqrt(3)-1);
    var G2 = (3-Math.sqrt(3))/6;

    var F3 = 1/3;
    var G3 = 1/6;

    // 2D simplex noise
    module.simplex2 = function(xin, yin) {
        var n0, n1, n2; // Noise contributions from the three corners
        // Skew the input space to determine which simplex cell we're in
        var s = (xin+yin)*F2; // Hairy factor for 2D
        var i = Math.floor(xin+s);
        var j = Math.floor(yin+s);
        var t = (i+j)*G2;
        var x0 = xin-i+t; // The x,y distances from the cell origin, unskewed.
        var y0 = yin-j+t;
        // For the 2D case, the simplex shape is an equilateral triangle.
        // Determine which simplex we are in.
        var i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords
        if(x0>y0) { // lower triangle, XY order: (0,0)->(1,0)->(1,1)
            i1=1; j1=0;
        } else {    // upper triangle, YX order: (0,0)->(0,1)->(1,1)
            i1=0; j1=1;
        }
        // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
        // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
        // c = (3-sqrt(3))/6
        var x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
        var y1 = y0 - j1 + G2;
        var x2 = x0 - 1 + 2 * G2; // Offsets for last corner in (x,y) unskewed coords
        var y2 = y0 - 1 + 2 * G2;
        // Work out the hashed gradient indices of the three simplex corners
        i &= 255;
        j &= 255;
        var gi0 = gradP[i+perm[j]];
        var gi1 = gradP[i+i1+perm[j+j1]];
        var gi2 = gradP[i+1+perm[j+1]];
        // Calculate the contribution from the three corners
        var t0 = 0.5 - x0*x0-y0*y0;
        if(t0<0) {
            n0 = 0;
        } else {
            t0 *= t0;
            n0 = t0 * t0 * gi0.dot2(x0, y0);  // (x,y) of grad3 used for 2D gradient
        }
        var t1 = 0.5 - x1*x1-y1*y1;
        if(t1<0) {
            n1 = 0;
        } else {
            t1 *= t1;
            n1 = t1 * t1 * gi1.dot2(x1, y1);
        }
        var t2 = 0.5 - x2*x2-y2*y2;
        if(t2<0) {
            n2 = 0;
        } else {
            t2 *= t2;
            n2 = t2 * t2 * gi2.dot2(x2, y2);
        }
        // Add contributions from each corner to get the final noise value.
        // The result is scaled to return values in the interval [-1,1].
        return 70 * (n0 + n1 + n2);
    };

    // 3D simplex noise
    module.simplex3 = function(xin, yin, zin) {
        var n0, n1, n2, n3; // Noise contributions from the four corners

        // Skew the input space to determine which simplex cell we're in
        var s = (xin+yin+zin)*F3; // Hairy factor for 2D
        var i = Math.floor(xin+s);
        var j = Math.floor(yin+s);
        var k = Math.floor(zin+s);

        var t = (i+j+k)*G3;
        var x0 = xin-i+t; // The x,y distances from the cell origin, unskewed.
        var y0 = yin-j+t;
        var z0 = zin-k+t;

        // For the 3D case, the simplex shape is a slightly irregular tetrahedron.
        // Determine which simplex we are in.
        var i1, j1, k1; // Offsets for second corner of simplex in (i,j,k) coords
        var i2, j2, k2; // Offsets for third corner of simplex in (i,j,k) coords
        if(x0 >= y0) {
            if(y0 >= z0)      { i1=1; j1=0; k1=0; i2=1; j2=1; k2=0; }
            else if(x0 >= z0) { i1=1; j1=0; k1=0; i2=1; j2=0; k2=1; }
            else              { i1=0; j1=0; k1=1; i2=1; j2=0; k2=1; }
        } else {
            if(y0 < z0)      { i1=0; j1=0; k1=1; i2=0; j2=1; k2=1; }
            else if(x0 < z0) { i1=0; j1=1; k1=0; i2=0; j2=1; k2=1; }
            else             { i1=0; j1=1; k1=0; i2=1; j2=1; k2=0; }
        }
        // A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
        // a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
        // a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
        // c = 1/6.
        var x1 = x0 - i1 + G3; // Offsets for second corner
        var y1 = y0 - j1 + G3;
        var z1 = z0 - k1 + G3;

        var x2 = x0 - i2 + 2 * G3; // Offsets for third corner
        var y2 = y0 - j2 + 2 * G3;
        var z2 = z0 - k2 + 2 * G3;

        var x3 = x0 - 1 + 3 * G3; // Offsets for fourth corner
        var y3 = y0 - 1 + 3 * G3;
        var z3 = z0 - 1 + 3 * G3;

        // Work out the hashed gradient indices of the four simplex corners
        i &= 255;
        j &= 255;
        k &= 255;
        var gi0 = gradP[i+   perm[j+   perm[k   ]]];
        var gi1 = gradP[i+i1+perm[j+j1+perm[k+k1]]];
        var gi2 = gradP[i+i2+perm[j+j2+perm[k+k2]]];
        var gi3 = gradP[i+ 1+perm[j+ 1+perm[k+ 1]]];

        // Calculate the contribution from the four corners
        var t0 = 0.6 - x0*x0 - y0*y0 - z0*z0;
        if(t0<0) {
            n0 = 0;
        } else {
            t0 *= t0;
            n0 = t0 * t0 * gi0.dot3(x0, y0, z0);  // (x,y) of grad3 used for 2D gradient
        }
        var t1 = 0.6 - x1*x1 - y1*y1 - z1*z1;
        if(t1<0) {
            n1 = 0;
        } else {
            t1 *= t1;
            n1 = t1 * t1 * gi1.dot3(x1, y1, z1);
        }
        var t2 = 0.6 - x2*x2 - y2*y2 - z2*z2;
        if(t2<0) {
            n2 = 0;
        } else {
            t2 *= t2;
            n2 = t2 * t2 * gi2.dot3(x2, y2, z2);
        }
        var t3 = 0.6 - x3*x3 - y3*y3 - z3*z3;
        if(t3<0) {
            n3 = 0;
        } else {
            t3 *= t3;
            n3 = t3 * t3 * gi3.dot3(x3, y3, z3);
        }
        // Add contributions from each corner to get the final noise value.
        // The result is scaled to return values in the interval [-1,1].
        return 32 * (n0 + n1 + n2 + n3);

    };

    // ##### Perlin noise stuff

    function fade(t) {
        return t*t*t*(t*(t*6-15)+10);
    }

    function lerp(a, b, t) {
        return (1-t)*a + t*b;
    }

    // 2D Perlin Noise
    module.perlin2 = function(x, y) {
        // Find unit grid cell containing point
        var X = Math.floor(x), Y = Math.floor(y);
        // Get relative xy coordinates of point within that cell
        x = x - X; y = y - Y;
        // Wrap the integer cells at 255 (smaller integer period can be introduced here)
        X = X & 255; Y = Y & 255;

        // Calculate noise contributions from each of the four corners
        var n00 = gradP[X+perm[Y]].dot2(x, y);
        var n01 = gradP[X+perm[Y+1]].dot2(x, y-1);
        var n10 = gradP[X+1+perm[Y]].dot2(x-1, y);
        var n11 = gradP[X+1+perm[Y+1]].dot2(x-1, y-1);

        // Compute the fade curve value for x
        var u = fade(x);

        // Interpolate the four results
        return lerp(
            lerp(n00, n10, u),
            lerp(n01, n11, u),
            fade(y));
    };

    // 3D Perlin Noise
    module.perlin3 = function(x, y, z) {
        // Find unit grid cell containing point
        var X = Math.floor(x), Y = Math.floor(y), Z = Math.floor(z);
        // Get relative xyz coordinates of point within that cell
        x = x - X; y = y - Y; z = z - Z;
        // Wrap the integer cells at 255 (smaller integer period can be introduced here)
        X = X & 255; Y = Y & 255; Z = Z & 255;

        // Calculate noise contributions from each of the eight corners
        var n000 = gradP[X+  perm[Y+  perm[Z  ]]].dot3(x,   y,     z);
        var n001 = gradP[X+  perm[Y+  perm[Z+1]]].dot3(x,   y,   z-1);
        var n010 = gradP[X+  perm[Y+1+perm[Z  ]]].dot3(x,   y-1,   z);
        var n011 = gradP[X+  perm[Y+1+perm[Z+1]]].dot3(x,   y-1, z-1);
        var n100 = gradP[X+1+perm[Y+  perm[Z  ]]].dot3(x-1,   y,   z);
        var n101 = gradP[X+1+perm[Y+  perm[Z+1]]].dot3(x-1,   y, z-1);
        var n110 = gradP[X+1+perm[Y+1+perm[Z  ]]].dot3(x-1, y-1,   z);
        var n111 = gradP[X+1+perm[Y+1+perm[Z+1]]].dot3(x-1, y-1, z-1);

        // Compute the fade curve value for x, y, z
        var u = fade(x);
        var v = fade(y);
        var w = fade(z);

        // Interpolate
        return lerp(
            lerp(
                lerp(n000, n100, u),
                lerp(n001, n101, u), w),
            lerp(
                lerp(n010, n110, u),
                lerp(n011, n111, u), w),
            v);
    };

    module.turbulence = function( x,y,z, size, octaves, lacunarity, gain )
    {
        lacunarity = lacunarity || 2;
        gain = gain || .5;

        var sum = 0;
        var  freq = size, amp = 1.0;
        for ( var i = 0; i < octaves; i++ )
        {
            var n = module.perlin3( freq * x, freq * y, freq * z );
            sum += n * amp;
            freq *= lacunarity;
            amp *= gain;
        }
        return sum;
    };

    return module;

}({});
/**
 * Created by nico on 17/09/2015.
 */

//MIT License
//Author: Max Irwin, 2011
//https://gist.github.com/binarymax/4071852
//Floodfill functions
function floodFill(x,y,fillcolor,ctx,out,width,height,tolerance) {

    var img = ctx.getImageData(0,0,width,height);
    var data = img.data;

    out.clearRect(0,0,width,height);
    var imgOut = out.getImageData(0,0,width,height);
    var outData = imgOut.data;

    var length = data.length;
    var Q = [];
    var i = (x+y*width)*4;
    var e = i, w = i, me, mw, w2 = width*4;
    var targetcolor = [data[i],data[i+1],data[i+2],data[i+3]];


    if(!pixelCompare(i,targetcolor,fillcolor,data,length,tolerance)) { return false; }
    Q.push(i);

    while(Q.length)
    {
        i = Q.pop();
        if(pixelCompareAndSet(i,targetcolor,fillcolor,data,outData,length,tolerance))
        {
            e = i;
            w = i;
            mw = parseInt(i/w2)*w2; //left bound
            me = mw+w2;	//right bound
            while(mw<(w-=4) && pixelCompareAndSet(w,targetcolor,fillcolor,data,outData, length,tolerance)); //go left until edge hit
            while(me>(e+=4) && pixelCompareAndSet(e,targetcolor,fillcolor,data,outData, length,tolerance)); //go right until edge hit

            for(var j=w;j<e;j+=4) {
                if(j-w2>=0 		&& pixelCompare(j-w2,targetcolor,fillcolor,data,length,tolerance)) Q.push(j-w2); //queue y-1
                if(j+w2<length	&& pixelCompare(j+w2,targetcolor,fillcolor,data,length,tolerance)) Q.push(j+w2); //queue y+1
            }
        }
    }

    ctx.putImageData(img,0,0);

    out.imgData = imgOut;
    out.data = imgOut.data;
    out.putImageData(imgOut,0,0);

}

function pixelCompare(i,targetcolor,fillcolor,data,length,tolerance) {

    if (i<0||i>=length) return false; //out of bounds
    //if (data[i+3]===0)  return true;  //surface is invisible

    if (
        (targetcolor[3] === fillcolor.a) &&
        (targetcolor[0] === fillcolor.r) && (targetcolor[1] === fillcolor.g) && (targetcolor[2] === fillcolor.b)) return false; //target is same as fill

    if (
        (targetcolor[3] === data[i+3]) &&
        (targetcolor[0] === data[i]  ) && (targetcolor[1] === data[i+1]) && (targetcolor[2] === data[i+2])) return true; //target matches surface

    if (
        Math.abs(targetcolor[3] - data[i+3])<=tolerance //(255-tolerance)
        && Math.abs(targetcolor[0] - data[i]  )<=tolerance
        && Math.abs(targetcolor[1] - data[i+1])<=tolerance
        && Math.abs(targetcolor[2] - data[i+2])<=tolerance) return true; //target to surface within tolerance

    return false; //no match
}

function pixelCompareAndSet(i,targetcolor,fillcolor,data, outData, length,tolerance)
{
    if(pixelCompare(i,targetcolor,fillcolor,data,length,tolerance))
    {
        //fill the color
        data[i]   = outData[i]   = fillcolor.r;
        data[i+1] = outData[i+1] = fillcolor.g;
        data[i+2] = outData[i+2] = fillcolor.b;
        data[i+3] = fillcolor.a;
            outData[i+3] =  0xFF;
        return true;
    }
    return false;
}


function getContext(w,h){
    var canvas = document.createElement( 'canvas' );
    canvas.width  = w;
    canvas.height = h;
    return canvas.getContext("2d");
}

function getImageData( canvas )
{
    var w = canvas.width;
    var h = canvas.height;
    return ctx.getImageData( 0,0,w,h );
}

var interval;
var w = 512;
var h = 512;
var ctx = getContext( w,h );
document.body.appendChild(ctx.canvas);
var out = getContext( w,h );
document.body.appendChild(out.canvas);
out.canvas.style.position = "absolute";
out.canvas.style.top = "0";
out.canvas.style.left = "0";
var fin = getContext( w,h );
document.body.appendChild(fin.canvas);
function init()
{
    cancelAnimationFrame( interval );



    var imgData = getImageData(ctx.canvas);

    var s = .075;
    for( var i = 0; i< imgData.data.length; i+=4 )
    {
        var x = ( i/4 % w );
        var y = ~~( i/4 / w );
        var val = ~~( 0xFF * Math.random() );
        val = ( simplex.simplex2( x * s, y * s ) ) < -0.25     ? 0xFF  : 0;

        imgData.data[ i ] =
        imgData.data[ i+1 ] =
        imgData.data[ i+2 ] = val;
        imgData.data[ i+3 ] = val;

    }

    ctx.putImageData(imgData, 0,0);

    componentLabelling();


}
function componentLabelling()
{
    var xy = firstNonTransparentPixel( ctx );
    if( xy != null )
    {
        floodFill( xy[0],xy[1], { r:0xFF, g:0x00, b:0xFF, a:0 }, ctx,out, w,h, 128 );

        xy = firstNonTransparentPixel( ctx );

        var r = getColorBoundsRect( out );
        if(r.w >= w-1 || r.h >= h-1 )
        {
            setTimeout( componentLabelling, 1 );
            return;
        }

      /*
        fin.strokeStyle = "#FFF";
        fin.strokeRect(r.x, r.y, r.w, r.h );
        */
        fin.drawImage(out.canvas,0,0);
      

        setTimeout( componentLabelling, 1 );
    }
}

function firstNonTransparentPixel(ctx) {

    var w = ctx.canvas.width;
    var h = ctx.canvas.height;
    var imgData = ctx.getImageData(0, 0, w, h );
    var data = imgData.data;
    var x, y, i = 0;
    while (i < (data.length / 4)) {
        if (data[i * 4 + 3] != 0) {
            x = ( i % w );
            y = ~~(i / w);
            return [x,y];
        }
        i++;
    }
    return null;
}


function getColorBoundsRect(ctx) {

    var w = ctx.canvas.width;
    var h = ctx.canvas.height;
    var imgData = ctx.getImageData(0, 0, w, h );
    var data = imgData.data;
    var r = { x: 10e10, y: 10e10, w: -10e10, h: -10e10};
    var x, y, i = 0;
    var _r = ~~(Math.random() * 0xFF ), _g = ~~(Math.random() * 0xFF ), _b = ~~(Math.random() * 0xFF );
    while (i < (data.length / 4))
    {
        if ( data[ i * 4 + 3 ] != 0)
        {
            x = ( i % w );
            y = ~~(i / w);

            if ( x < r.x )r.x = x;
            if ( x > r.w )r.w = x;
            if ( y < r.y )r.y = y;
            if ( y > r.h )r.h = y;
            data[ i * 4 ]       = _r;
            data[ i * 4 + 1 ]   = _g;
            data[ i * 4 + 2 ]   = _b;
            data[ i * 4 + 3 ]   = 0xFF;
        }
        ++i;
    }
    r.w -= r.x;
    r.h -= r.y;
    ctx.putImageData( imgData, 0, 0 );
    return r;

}



function update()
{
    interval = requestAnimationFrame( update );




}

///////////////////////////////////
window.onload = function( e )
{
    init();
    //update();
};


window.onmousedown = function(e)
{
    console.log(e.clientX, e.clientY );

}
              
            
!
999px

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