} // 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
