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/**
* @author WestLangley / http://github.com/WestLangley
*/
import {
Color,
LightProbe,
LinearEncoding,
SphericalHarmonics3,
Vector3,
sRGBEncoding
} from "../../../build/three.module.js";
var LightProbeGenerator = {
// https://www.ppsloan.org/publications/StupidSH36.pdf
fromCubeTexture: function ( cubeTexture ) {
var norm, lengthSq, weight, totalWeight = 0;
var coord = new Vector3();
var dir = new Vector3();
var color = new Color();
var shBasis = [ 0, 0, 0, 0, 0, 0, 0, 0, 0 ];
var sh = new 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
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 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 Vector3();
var dir = new Vector3();
var color = new Color();
var shBasis = [ 0, 0, 0, 0, 0, 0, 0, 0, 0 ];
var sh = new 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
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 LightProbe( sh );
}
};
var convertColorToLinear = function ( color, encoding ) {
switch ( encoding ) {
case sRGBEncoding:
color.convertSRGBToLinear();
break;
case LinearEncoding:
break;
default:
console.warn( 'WARNING: LightProbeGenerator convertColorToLinear() encountered an unsupported encoding.' );
break;
}
return color;
};
export { LightProbeGenerator };
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