text: /**
   * @author WestLangley / http://github.com/WestLangley
   */
  
  THREE.LightProbeGenerator = {
  
  	// https://www.ppsloan.org/publications/StupidSH36.pdf
  	fromCubeTexture: function ( cubeTexture ) {
  
  		var norm, lengthSq, weight, totalWeight = 0;
  
  		var coord = new THREE.Vector3();
  
  		var dir = new THREE.Vector3();
  
  		var color = new THREE.Color();
  
  		var shBasis = [ 0, 0, 0, 0, 0, 0, 0, 0, 0 ];
  
  		var sh = new THREE.SphericalHarmonics3();
  		var shCoefficients = sh.coefficients;
  
  		for ( var faceIndex = 0; faceIndex < 6; faceIndex ++ ) {
  
  			var image = cubeTexture.image[ faceIndex ];
  
  			var width = image.width;
  			var height = image.height;
  
  			var canvas = document.createElement( 'canvas' );
  
  			canvas.width = width;
  			canvas.height = height;
  
  			var context = canvas.getContext( '2d' );
  
  			context.drawImage( image, 0, 0, width, height );
  
  			var imageData = context.getImageData( 0, 0, width, height );
  
  			var data = imageData.data;
  
  			var imageWidth = imageData.width; // assumed to be square
  
  			var pixelSize = 2 / imageWidth;
  
  			for ( var i = 0, il = data.length; i < il; i += 4 ) { // RGBA assumed
  
  				// pixel color
  				color.setRGB( data[ i ] / 255, data[ i + 1 ] / 255, data[ i + 2 ] / 255 );
  
  				// convert to linear color space
  				convertColorToLinear( color, cubeTexture.encoding );
  
  				// pixel coordinate on unit cube
  
  				var pixelIndex = i / 4;
  
  				var col = - 1 + ( pixelIndex % imageWidth + 0.5 ) * pixelSize;
  
  				var row = 1 - ( Math.floor( pixelIndex / imageWidth ) + 0.5 ) * pixelSize;
  
  				switch ( faceIndex ) {
  
  					case 0: coord.set( - 1, row, - col ); break;
  
  					case 1: coord.set( 1, row, col ); break;
  
  					case 2: coord.set( - col, 1, - row ); break;
  
  					case 3: coord.set( - col, - 1, row ); break;
  
  					case 4: coord.set( - col, row, 1 ); break;
  
  					case 5: coord.set( col, row, - 1 ); break;
  
  				}
  
  				// weight assigned to this pixel
  
  				lengthSq = coord.lengthSq();
  
  				weight = 4 / ( Math.sqrt( lengthSq ) * lengthSq );
  
  				totalWeight += weight;
  
  				// direction vector to this pixel
  				dir.copy( coord ).normalize();
  
  				// evaluate SH basis functions in direction dir
  				THREE.SphericalHarmonics3.getBasisAt( dir, shBasis );
  
  				// accummuulate
  				for ( var j = 0; j < 9; j ++ ) {
  
  					shCoefficients[ j ].x += shBasis[ j ] * color.r * weight;
  					shCoefficients[ j ].y += shBasis[ j ] * color.g * weight;
  					shCoefficients[ j ].z += shBasis[ j ] * color.b * weight;
  
  				}
  
  			}
  
  		}
  
  		// normalize
  		norm = ( 4 * Math.PI ) / totalWeight;
  
  		for ( var j = 0; j < 9; j ++ ) {
  
  			shCoefficients[ j ].x *= norm;
  			shCoefficients[ j ].y *= norm;
  			shCoefficients[ j ].z *= norm;
  
  		}
  
  		return new THREE.LightProbe( sh );
  
  	},
  
  	fromRenderTargetCube: function ( renderer, renderTargetCube ) {
  
  		// The renderTarget must be set to RGBA in order to make readRenderTargetPixels works
  		var norm, lengthSq, weight, totalWeight = 0;
  
  		var coord = new THREE.Vector3();
  
  		var dir = new THREE.Vector3();
  
  		var color = new THREE.Color();
  
  		var shBasis = [ 0, 0, 0, 0, 0, 0, 0, 0, 0 ];
  
  		var sh = new THREE.SphericalHarmonics3();
  		var shCoefficients = sh.coefficients;
  
  		for ( var faceIndex = 0; faceIndex < 6; faceIndex ++ ) {
  
  			var imageWidth = renderTargetCube.width; // assumed to be square
  			var data = new Uint8Array( imageWidth * imageWidth * 4 );
  			renderer.readRenderTargetPixels( renderTargetCube, 0, 0, imageWidth, imageWidth, data, faceIndex );
  
  			var pixelSize = 2 / imageWidth;
  
  			for ( var i = 0, il = data.length; i < il; i += 4 ) { // RGBA assumed
  
  				// pixel color
  				color.setRGB( data[ i ] / 255, data[ i + 1 ] / 255, data[ i + 2 ] / 255 );
  
  				// convert to linear color space
  				convertColorToLinear( color, renderTargetCube.texture.encoding );
  
  				// pixel coordinate on unit cube
  
  				var pixelIndex = i / 4;
  
  				var col = - 1 + ( pixelIndex % imageWidth + 0.5 ) * pixelSize;
  
  				var row = 1 - ( Math.floor( pixelIndex / imageWidth ) + 0.5 ) * pixelSize;
  
  				switch ( faceIndex ) {
  
  					case 0: coord.set( 1, row, - col ); break;
  
  					case 1: coord.set( - 1, row, col ); break;
  
  					case 2: coord.set( col, 1, - row ); break;
  
  					case 3: coord.set( col, - 1, row ); break;
  
  					case 4: coord.set( col, row, 1 ); break;
  
  					case 5: coord.set( - col, row, - 1 ); break;
  
  				}
  
  				// weight assigned to this pixel
  
  				lengthSq = coord.lengthSq();
  
  				weight = 4 / ( Math.sqrt( lengthSq ) * lengthSq );
  
  				totalWeight += weight;
  
  				// direction vector to this pixel
  				dir.copy( coord ).normalize();
  
  				// evaluate SH basis functions in direction dir
  				THREE.SphericalHarmonics3.getBasisAt( dir, shBasis );
  
  				// accummuulate
  				for ( var j = 0; j < 9; j ++ ) {
  
  					shCoefficients[ j ].x += shBasis[ j ] * color.r * weight;
  					shCoefficients[ j ].y += shBasis[ j ] * color.g * weight;
  					shCoefficients[ j ].z += shBasis[ j ] * color.b * weight;
  
  				}
  
  			}
  
  		}
  
  		// normalize
  		norm = ( 4 * Math.PI ) / totalWeight;
  
  		for ( var j = 0; j < 9; j ++ ) {
  
  			shCoefficients[ j ].x *= norm;
  			shCoefficients[ j ].y *= norm;
  			shCoefficients[ j ].z *= norm;
  
  		}
  
  		return new THREE.LightProbe( sh );
  
  	}
  
  };
  
  var convertColorToLinear = function ( color, encoding ) {
  
  	switch ( encoding ) {
  
  		case THREE.sRGBEncoding:
  
  			color.convertSRGBToLinear();
  			break;
  
  		case THREE.LinearEncoding:
  
  			break;
  
  		default:
  
  			console.warn( 'WARNING: LightProbeGenerator convertColorToLinear() encountered an unsupported encoding.' );
  			break;
  
  	}
  
  	return color;
  
  };
  