fromCubeRenderTarget static method

Implementation

static LightProbe fromCubeRenderTarget(WebGLRenderer renderer,WebGLCubeRenderTarget cubeRenderTarget ) {
	// The renderTarget must be set to RGBA in order to make readRenderTargetPixels works
	double totalWeight = 0;
	final coord = Vector3();
	final dir = Vector3();
	final color = Color();
	final List<double> shBasis = [ 0, 0, 0, 0, 0, 0, 0, 0, 0 ];

	final sh = SphericalHarmonics3();
	final shCoefficients = sh.coefficients;
	final dataType = cubeRenderTarget.texture.type;

	for (int faceIndex = 0; faceIndex < 6; faceIndex ++ ) {
		final imageWidth = cubeRenderTarget.width; // assumed to be square

		NativeArray data;

		if ( dataType == HalfFloatType ) {
			data = Uint16Array( imageWidth * imageWidth * 4 );
		}
      else {
			// assuming UnsignedByteType
			data = Uint8Array( imageWidth * imageWidth * 4 );
		}

		renderer.readRenderTargetPixels( cubeRenderTarget, 0, 0, imageWidth, imageWidth, data, faceIndex );

		final pixelSize = 2 / imageWidth;

		for (int i = 0, il = data.length; i < il; i += 4 ) { // RGBA assumed
			double r, g, b;

			if ( dataType == HalfFloatType ) {
				r = MathUtils.fromHalfFloat( data[ i ] );
				g = MathUtils.fromHalfFloat( data[ i + 1 ] );
				b = MathUtils.fromHalfFloat( data[ i + 2 ] );
			} else {
				r = data[i] / 255;
				g = data[i + 1] / 255;
				b = data[i + 2] / 255;
			}

			// pixel color
			color.setRGB( r, g, b );

			// convert to linear color space
			convertColorToLinear( color, cubeRenderTarget.texture.colorSpace );

			// pixel coordinate on unit cube

			final pixelIndex = i / 4;
			final col = - 1 + ( pixelIndex % imageWidth + 0.5 ) * pixelSize;
			final row = 1 - (( pixelIndex / imageWidth ).floor() + 0.5 ) * pixelSize;

			switch ( faceIndex ) {
				case 0: coord.setValues( 1, row, - col ); break;
				case 1: coord.setValues( - 1, row, col ); break;
				case 2: coord.setValues( col, 1, - row ); break;
				case 3: coord.setValues( col, - 1, row ); break;
				case 4: coord.setValues( col, row, 1 ); break;
				case 5: coord.setValues( - col, row, - 1 ); break;
			}

			// weight assigned to this pixel

			final lengthSq = coord.length2;

			final weight = 4 / ( math.sqrt( lengthSq ) * lengthSq );

			totalWeight += weight;

			// direction vector to this pixel
			dir.setFrom( coord ).normalize();

			// evaluate SH basis functions in direction dir
			SphericalHarmonics3.getBasisAt( dir, shBasis );

			// accummuulate
			for (int j = 0; j < 9; j ++ ) {
				shCoefficients[ j ].x += shBasis[ j ] * color.red * weight;
				shCoefficients[ j ].y += shBasis[ j ] * color.green * weight;
				shCoefficients[ j ].z += shBasis[ j ] * color.blue * weight;
			}
		}
	}

	// normalize
	final norm = ( 4 * math.pi ) / totalWeight;

	for (int j = 0; j < 9; j ++ ) {
		shCoefficients[ j ].x *= norm;
		shCoefficients[ j ].y *= norm;
		shCoefficients[ j ].z *= norm;
	}

	return LightProbe( sh );
}