First commit

README.md

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+Hello

lib/perlin.js

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+function Perlin( table ) {
+	this._table = table || Perlin.makeTable( 255 );
+
+	this.octaves = 10;
+	this.frequency = .1;
+	this.persistence = .5;
+}
+
+Perlin.random = function ( ) {
+	return Math.random( );
+};
+
+Perlin.makeTable = function ( size ) {
+	var result = [ ];
+
+	for ( var n = 0; n < size; ++ n )
+		result[ n ] = Perlin.random( );
+
+	return result;
+};
+
+Perlin.cosineInterpolate = function ( a, b, t ) {
+	var c = ( 1 - Math.cos( t * Math.PI ) ) * .5;
+
+	return ( 1 - c ) * a + c * b;
+};
+
+Perlin.prototype = {
+
+	_randify : function ( n ) {
+		return this._table[ Math.floor( n % this._table.length ) ];
+	},
+
+	_noise : function ( point ) {
+		var value = 0;
+		var dimensions = point.length;
+
+		for (var dimension = 0; dimension < dimensions; ++ dimension )
+			value = this._randify( value * 85000 + point[ dimension ] );
+
+		return value;
+	},
+
+	_smooth : function ( point, dimension ) {
+		if ( dimension < 0 )
+			return this._noise( point );
+
+		var value = point[ dimension ];
+		var integer = Math.floor( value );
+		var fractional = value - integer;
+
+		point[ dimension ] = integer;
+		var a = this._smooth( point, dimension - 1 );
+
+		point[ dimension ] = integer + 1;
+		var b = this._smooth( point, dimension - 1 );
+
+		point[ dimension ] = value;
+
+		return Perlin.cosineInterpolate( a, b, fractional );
+	},
+
+	_perlin : function ( point ) {
+		var value = 0;
+		var amplitude = 1;
+
+		var octaves = this.octaves;
+		var frequency = this.frequency;
+		var persistence = this.persistence;
+
+		var copy = point.slice( );
+		var dimensions = copy.length;
+
+		for ( var i = 0; i < octaves; ++ i )
+		{
+			for ( var dimension = 0; dimension < dimensions; ++ dimension )
+				copy[ dimension ] = point[ dimension ] * frequency;
+
+			value += this._noise( copy, dimensions - 1 ) * amplitude;
+
+			amplitude *= persistence;
+			frequency *= 2;
+		}
+
+		var limiter = ( 1 - persistence ) / ( 1 - amplitude );
+		return value * limiter;
+	},
+
+	_generate : function ( start, size, callback, dimension ) {
+		if ( dimension < 0 )
+			return callback( start, this._perlin( start ) );
+
+		for ( var end = start[ dimension ] + size[ dimension ]; start[ dimension ] < end; ++ start[ dimension ] )
+			this._generate( start, size, callback, dimension - 1 );
+
+		start[ dimension ] -= size[ dimension ];
+		return null;
+	},
+
+	generate : function ( start, size, callback ) {
+		this._generate( start, size, callback, start.length - 1 );
+	}
+
+};

test/demo.js

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+window.addEventListener( 'load', function ( ) {
+	var map    = new Perlin( );
+
+	var canvas = document.getElementById( 'canvas' );
+	var ctx    = canvas.getContext( '2d' );
+
+	var width  = canvas.width;
+	var height = canvas.height;
+
+	var buffer = ctx.createImageData( width, height );
+
+	function update( ) {
+		map.generate( [ 0, 0 ], [ width, height ], function ( point, value ) {
+			var idx = ( point[ 1 ] * width + point[ 0 ] ) * 4;
+			var clr = Math.floor( ( value + 1 ) / 2 * 255 );
+			console.log(clr);
+
+			buffer.data[ idx + 0 ] = clr;
+			buffer.data[ idx + 1 ] = clr;
+			buffer.data[ idx + 2 ] = clr;
+			buffer.data[ idx + 3 ] = 255;
+		});
+
+		ctx.putImageData( buffer, 0, 0 );
+	}
+
+	update( );
+} );

test/index.html

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+<canvas id="canvas" width="500" height="500"></canvas>
+<script src="../lib/perlin.js"></script>
+<script src="demo.js"></script>