private static Xen.Ex.SphericalHarmonicL2RGB ExtractSphericalHarmonicForCubeFace(Matrix faceTransform, Vector3[] colourDataRGB, int faceSize)
{
Xen.Ex.SphericalHarmonicL2RGB sh = new Xen.Ex.SphericalHarmonicL2RGB();
//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.
//See the remarks in SphericalHarmonicL2RGB for more detals.
float directionStep = 2.0f / (faceSize - 1.0f);
int pixelIndex = 0;
float dirY = 1.0f;
for (int y = 0; y < faceSize; y++)
{
Xen.Ex.SphericalHarmonicL2RGB lineSh = new Xen.Ex.SphericalHarmonicL2RGB();
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;
//decode the RGBM colour
Vector3 rgb = colourDataRGB[pixelIndex++];
//Add it to the SH
lineSh.AddLight(ref rgb, ref direction, weight);
dirX += directionStep;
}
//average the SH
if (lineSh.Weighting > 0)
{
lineSh /= 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 /= sh.Weighting;
}
return(sh);
}
private static Xen.Ex.SphericalHarmonicL2RGB ExtractSphericalHarmonicForCubeFace(Matrix faceTransform, Vector3[] colourDataRGB, int faceSize)
{
Xen.Ex.SphericalHarmonicL2RGB sh = new Xen.Ex.SphericalHarmonicL2RGB();
//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.
//See the remarks in SphericalHarmonicL2RGB for more detals.
float directionStep = 2.0f / (faceSize - 1.0f);
int pixelIndex = 0;
float dirY = 1.0f;
for (int y = 0; y < faceSize; y++)
{
Xen.Ex.SphericalHarmonicL2RGB lineSh = new Xen.Ex.SphericalHarmonicL2RGB();
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;
//decode the RGBM colour
Vector3 rgb = colourDataRGB[pixelIndex++];
//Add it to the SH
lineSh.AddLight(ref rgb, ref direction, weight);
dirX += directionStep;
}
//average the SH
if (lineSh.Weighting > 0)
lineSh /= 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 /= sh.Weighting;
return sh;
}
