} // GetWeightedAverageLightInputFromSphere private static SphericalHarmonicL2 ExtractSphericalHarmonicForCubeFace(Matrix faceTransform, Color[] colorDataRgb, int faceSize) { SphericalHarmonicL2 sh = new SphericalHarmonicL2(); // For each pixel in the face, generate it's SH contribution. // Treat each pixel in the cube as a light source, which gets added to the SH. // This is used to generate an indirect lighting SH for the scene. float directionStep = 2.0f / (faceSize - 1.0f); int pixelIndex = 0; float dirY = 1.0f; for (int y = 0; y < faceSize; y++) { SphericalHarmonicL2 lineSh = new SphericalHarmonicL2(); float dirX = -1.0f; for (int x = 0; x < faceSize; x++) { //the direction to the pixel in the cube Vector3 direction = new Vector3(dirX, dirY, 1); Vector3.TransformNormal(ref direction, ref faceTransform, out direction); //length of the direction vector float length = direction.Length(); //approximate area of the pixel (pixels close to the cube edges appear smaller when projected) float weight = 1.0f / length; //normalise: direction.X *= weight; direction.Y *= weight; direction.Z *= weight; Vector3 rgbFloat; Color rgbm = colorDataRgb[pixelIndex++]; rgbFloat = rgbm.ToVector3(); //Add it to the SH lineSh.AddLight(rgbFloat, direction, weight); dirX += directionStep; } //average the SH if (lineSh.weighting > 0) { lineSh *= 1 / lineSh.weighting; } // Add the line to the full SH // (SH is generated line by line to ease problems with floating point accuracy loss) sh += lineSh; dirY -= directionStep; } if (sh.weighting > 0) { sh *= 1 / sh.weighting; } return(sh); } // ExtractSphericalHarmonicForCubeFace
} // GetWeightedAverageLightInputFromSphere private static SphericalHarmonicL2 ExtractSphericalHarmonicForCubeFace(Matrix faceTransform, Color[] colorDataRgb, int faceSize) { SphericalHarmonicL2 sh = new SphericalHarmonicL2(); // For each pixel in the face, generate it's SH contribution. // Treat each pixel in the cube as a light source, which gets added to the SH. // This is used to generate an indirect lighting SH for the scene. float directionStep = 2.0f / (faceSize - 1.0f); int pixelIndex = 0; float dirY = 1.0f; for (int y = 0; y < faceSize; y++) { SphericalHarmonicL2 lineSh = new SphericalHarmonicL2(); float dirX = -1.0f; for (int x = 0; x < faceSize; x++) { //the direction to the pixel in the cube Vector3 direction = new Vector3(dirX, dirY, 1); Vector3.TransformNormal(ref direction, ref faceTransform, out direction); //length of the direction vector float length = direction.Length(); //approximate area of the pixel (pixels close to the cube edges appear smaller when projected) float weight = 1.0f / length; //normalise: direction.X *= weight; direction.Y *= weight; direction.Z *= weight; Vector3 rgbFloat; Color rgbm = colorDataRgb[pixelIndex++]; rgbFloat = rgbm.ToVector3(); //Add it to the SH lineSh.AddLight(rgbFloat, direction, weight); dirX += directionStep; } //average the SH if (lineSh.weighting > 0) lineSh *= 1 / lineSh.weighting; // Add the line to the full SH // (SH is generated line by line to ease problems with floating point accuracy loss) sh += lineSh; dirY -= directionStep; } if (sh.weighting > 0) sh *= 1 / sh.weighting; return sh; } // ExtractSphericalHarmonicForCubeFace