Vector2f propagate_uv(Vector3f pos, Vector2f nbrUV, ref Frame3f fNbr, ref Frame3f fSeed)
{
Vector2f local_uv = compute_local_uv(ref fNbr, pos);
Frame3f fSeedToLocal = fSeed;
fSeedToLocal.AlignAxis(2, fNbr.Z);
Vector3f vAlignedSeedX = fSeedToLocal.X;
Vector3f vLocalX = fNbr.X;
float fCosTheta = vLocalX.Dot(vAlignedSeedX);
// compute rotated min-dist vector for this particle
float fTmp = 1 - fCosTheta * fCosTheta;
if (fTmp < 0)
{
fTmp = 0; // need to clamp so that sqrt works...
}
float fSinTheta = (float)Math.Sqrt(fTmp);
Vector3f vCross = vLocalX.Cross(vAlignedSeedX);
if (vCross.Dot(fNbr.Z) < 0) // get the right sign...
{
fSinTheta = -fSinTheta;
}
Matrix2f mFrameRotate = new Matrix2f(fCosTheta, fSinTheta, -fSinTheta, fCosTheta);
return(nbrUV + mFrameRotate * local_uv);
}
public override MeshGenerator Generate()
{
int N = (PointIndicesCount == -1) ? PointIndices.Count() : PointIndicesCount;
vertices = new VectorArray3d(N * 3);
uv = null;
normals = new VectorArray3f(vertices.Count);
triangles = new IndexArray3i(N);
Matrix2f matRot = new Matrix2f(120 * MathUtil.Deg2Radf);
Vector2f uva = new Vector2f(0, Radius);
Vector2f uvb = matRot * uva;
Vector2f uvc = matRot * uvb;
int vi = 0;
int ti = 0;
foreach (int pid in PointIndices)
{
Vector3d v = PointF(pid);
Vector3d n = NormalF(pid);
Frame3f f = new Frame3f(v, n);
triangles.Set(ti++, vi, vi + 1, vi + 2, Clockwise);
vertices[vi++] = f.FromPlaneUV(uva, 2);
vertices[vi++] = f.FromPlaneUV(uvb, 2);
vertices[vi++] = f.FromPlaneUV(uvc, 2);
}
return(this);
}
public void EigenDecomposition(ref Matrix2f rot, ref Matrix2f diag)
{
float sum = Math.Abs(m00) + Math.Abs(m11);
if (Math.Abs(m01) + sum == sum)
{
// The matrix M is diagonal (within numerical round-off).
rot.m00 = (float)1;
rot.m01 = (float)0;
rot.m10 = (float)0;
rot.m11 = (float)1;
diag.m00 = m00;
diag.m01 = (float)0;
diag.m10 = (float)0;
diag.m11 = m11;
return;
}
float trace = m00 + m11;
float diff = m00 - m11;
float discr = (float)Math.Sqrt(diff * diff + ((float)4) * m01 * m01);
float eigVal0 = 0.5f * (trace - discr);
float eigVal1 = 0.5f * (trace + discr);
diag.SetToDiagonal(eigVal0, eigVal1);
float cs, sn;
if (diff >= 0.0)
{
cs = m01;
sn = eigVal0 - m00;
}
else
{
cs = eigVal0 - m11;
sn = m01;
}
float invLength = 1.0f / (float)Math.Sqrt(cs * cs + sn * sn);
cs *= invLength;
sn *= invLength;
rot.m00 = cs;
rot.m01 = -sn;
rot.m10 = sn;
rot.m11 = cs;
}
