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VertexCurvature method added.

This commit is contained in:
Paolo Cignoni 2008-04-23 16:37:15 +00:00
parent c918066b8e
commit 35daaec635
1 changed files with 87 additions and 9 deletions
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96
vcg/complex/trimesh/update/curvature.h
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@ -23,6 +23,9 @@
/****************************************************************************
History
$Log: not supported by cvs2svn $
Revision 1.6 2008/04/04 10:26:12 cignoni
Cleaned up names, now Kg() gives back Gaussian Curvature (k1*k2), while Kh() gives back Mean Curvature 1/2(k1+k2)
Revision 1.5 2008/03/25 11:00:56 ganovelli
fixed bugs sign of principal direction and mean curvature value
@ -67,13 +70,16 @@ class UpdateCurvature
{
public:
typedef typename MeshType::FaceIterator FaceIterator;
typedef typename MeshType::VertexIterator VertexIterator;
typedef typename MeshType::VertContainer VertContainer;
typedef typename MeshType::VertexType VertexType;
typedef typename MeshType::FaceType FaceType;
typedef typename MeshType::CoordType CoordType;
typedef typename CoordType::ScalarType ScalarType;
typedef typename MeshType::FaceType FaceType;
typedef typename MeshType::FacePointer FacePointer;
typedef typename MeshType::FaceIterator FaceIterator;
typedef typename MeshType::VertexIterator VertexIterator;
typedef typename MeshType::VertContainer VertContainer;
typedef typename MeshType::VertexType VertexType;
typedef typename MeshType::VertexPointer VertexPointer;
typedef vcg::face::VFIterator<FaceType> VFIteratorType;
typedef typename MeshType::CoordType CoordType;
typedef typename CoordType::ScalarType ScalarType;
private:
@ -94,7 +100,6 @@ public:
pages = "902--907",
URL = "http://dx.doi.org/10.1109/ICCV.1995.466840",
bibsource = "http://www.visionbib.com/bibliography/describe440.html#TT32253",
}
*/
static void PrincipalDirections(MeshType &m) {
@ -382,7 +387,80 @@ Discrete Differential-Geometry Operators for Triangulated 2-Manifolds Mark Meyer
TDContr.Stop();
}
/* Update the mean and the gaussian curvature of a vertex, using the
* VF adiacency to walk around the vertex. Return the voronoi area
* around the vertex.
* if norm == true, the mean and the gaussian curvature are normalized
* based on the paper
* "optimizing 3d triangulations using discrete curvature analysis"
* http://www2.in.tu-clausthal.de/~hormann/papers/Dyn.2001.OTU.pdf
* */
static float VertexCurvature(VertexPointer v, bool norm = true)
{
// VFAdjacency required!
assert(FaceType::HasVFAdjacency());
assert(VertexType::HasVFAdjacency());
VFIteratorType vfi(v);
float A = 0;
v->Kh() = 0;
v->Kg() = 2 * M_PI;
while (!vfi.End()) {
if (!vfi.F()->IsD()) {
FacePointer f = vfi.F();
int i = vfi.I();
VertexPointer v0 = f->V0(i), v1 = f->V1(i), v2 = f->V2(i);
float ang0 = math::Abs(Angle(v1->P() - v0->P(), v2->P() - v0->P() ));
float ang1 = math::Abs(Angle(v0->P() - v1->P(), v2->P() - v1->P() ));
float ang2 = M_PI - ang0 - ang1;
float s01 = SquaredDistance(v1->P(), v0->P());
float s02 = SquaredDistance(v2->P(), v0->P());
// voronoi cell of current vertex
if (ang0 >= M_PI/2)
A += (0.5f * DoubleArea(*f) - (s01 * tan(ang1) + s02 * tan(ang2)) / 8.0 );
else if (ang1 >= M_PI/2)
A += (s01 * tan(ang0)) / 8.0;
else if (ang2 >= M_PI/2)
A += (s02 * tan(ang0)) / 8.0;
else // non obctuse triangle
A += ((s02 / tan(ang1)) + (s01 / tan(ang2))) / 8.0;
// gaussian curvature update
v->Kg() -= ang0;
// mean curvature update
ang1 = math::Abs(Angle(f->N(), v1->N()));
ang2 = math::Abs(Angle(f->N(), v2->N()));
v->Kh() += ( (math::Sqrt(s01) / 2.0) * ang1 +
(math::Sqrt(s02) / 2.0) * ang2 );
}
++vfi;
}
v->Kh() /= 4.0f;
if(norm) {
if(A <= std::numeric_limits<float>::epsilon()) {
v->Kh() = 0;
v->Kg() = 0;
}
else {
v->Kh() /= A;
v->Kg() /= A;
}
}
return A;
}
};