From 7f38262616002cbdd34db3f2a496ebd140fe86ed Mon Sep 17 00:00:00 2001
From: Paolo Cignoni <paolo.cignoni@isti.cnr.it>
Date: Sun, 10 Sep 2017 18:09:08 +0200
Subject: [PATCH] corrected curvature issues #25

(wrong requirements, missing components...)
---
 .../trimesh_curvature/trimesh_curvature.cpp   | 24 +++++++++----------
 vcg/complex/algorithms/update/curvature.h     | 11 +++++----
 2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/apps/sample/trimesh_curvature/trimesh_curvature.cpp b/apps/sample/trimesh_curvature/trimesh_curvature.cpp
index e5458d72..8569c6e5 100644
--- a/apps/sample/trimesh_curvature/trimesh_curvature.cpp
+++ b/apps/sample/trimesh_curvature/trimesh_curvature.cpp
@@ -25,8 +25,6 @@
 
 \brief an example showing the various techniques for computing curvatures
 
-This file contain a minimal example of the library
-
 */
 #include <vcg/complex/complex.h>
 
@@ -42,8 +40,8 @@ struct MyUsedTypes : public vcg::UsedTypes<	vcg::Use<MyVertex>   ::AsVertexType,
                                             vcg::Use<MyEdge>     ::AsEdgeType,
                                             vcg::Use<MyFace>     ::AsFaceType>{};
 
-class MyVertex  : public vcg::Vertex<MyUsedTypes, vcg::vertex::Coord3f, vcg::vertex::Normal3f, vcg::vertex::BitFlags  >{};
-class MyFace    : public vcg::Face< MyUsedTypes, vcg::face::FFAdj,  vcg::face::VertexRef, vcg::face::BitFlags > {};
+class MyVertex  : public vcg::Vertex<MyUsedTypes, vcg::vertex::Coord3f, vcg::vertex::Normal3f, vcg::vertex::VFAdj, vcg::vertex::CurvatureDirf, vcg::vertex::Curvaturef, vcg::vertex::BitFlags  >{};
+class MyFace    : public vcg::Face< MyUsedTypes, vcg::face::FFAdj, vcg::face::VFAdj, vcg::face::VertexRef, vcg::face::BitFlags > {};
 class MyEdge    : public vcg::Edge<MyUsedTypes>{};
 class MyMesh    : public vcg::tri::TriMesh< std::vector<MyVertex>, std::vector<MyFace> , std::vector<MyEdge>  > {};
 
@@ -51,18 +49,20 @@ int main( int /*argc*/, char **/*argv*/ )
 {
   MyMesh m;
   vcg::tri::Torus(m,30,10);
-  vcg::tri::io::ExporterOFF<MyMesh>::Save(m,"torus.off");
-
+  
   vcg::tri::UpdateTopology<MyMesh>::FaceFace(m);
-//  vcg::tri::UpdateCurvature<MyMesh>::VertexCurvature(m);
+  vcg::tri::UpdateTopology<MyMesh>::VertexFace(m);
+  
+  // Two different techniques for computing Discrete Gaussian and Mean Curvature
+  // they require the presence of the vertex::Curvature component
+  vcg::tri::UpdateCurvature<MyMesh>::PerVertex(m);
   vcg::tri::UpdateCurvature<MyMesh>::MeanAndGaussian(m);
+  
+  // Two different techniques for computing Principal Curvature Directions 
+  // they require the presence of the vertex::CurvatureDir component
   vcg::tri::UpdateCurvature<MyMesh>::PrincipalDirections(m);
-  //vcg::tri::UpdateCurvature<MyMesh>::PrincipalDirectionsNormalCycles(m);
-  vcg::tri::UpdateCurvature<MyMesh>::PrincipalDirectionsPCA(m,m.bbox.Diag()/100);
-
-  vcg::tri::UpdateNormal<MyMesh>::PerVertexNormalized(m);
+  vcg::tri::UpdateCurvature<MyMesh>::PrincipalDirectionsNormalCycle(m);
   printf("Input mesh  vn:%i fn:%i\n",m.VN(),m.FN());
-  printf( "Mesh has %i vert and %i faces\n", m.VN(), m.FN() );
 
   return 0;
 }
diff --git a/vcg/complex/algorithms/update/curvature.h b/vcg/complex/algorithms/update/curvature.h
index 918d5ad7..5b9a5364 100644
--- a/vcg/complex/algorithms/update/curvature.h
+++ b/vcg/complex/algorithms/update/curvature.h
@@ -400,6 +400,7 @@ For further details, please, refer to: \n
 static void MeanAndGaussian(MeshType & m)
 {
   tri::RequireFFAdjacency(m);
+  tri::RequirePerVertexCurvature(m);
 
   float area0, area1, area2, angle0, angle1, angle2;
   FaceIterator fi;
@@ -540,6 +541,7 @@ static void MeanAndGaussian(MeshType & m)
         while (!vfi.End()) {
             if (!vfi.F()->IsD()) {
                 FacePointer f = vfi.F();
+                CoordType nf = TriangleNormal(*f);
                 int i = vfi.I();
                 VertexPointer v0 = f->V0(i), v1 = f->V1(i), v2 = f->V2(i);
 
@@ -564,8 +566,8 @@ static void MeanAndGaussian(MeshType & m)
                 v->Kg() -= ang0;
 
                 // mean curvature update
-                ang1 = math::Abs(Angle(f->N(), v1->N()));
-                ang2 = math::Abs(Angle(f->N(), v2->N()));
+                ang1 = math::Abs(Angle(nf, v1->N()));
+                ang2 = math::Abs(Angle(nf, v2->N()));
                 v->Kh() += ( (math::Sqrt(s01) / 2.0) * ang1 +
                              (math::Sqrt(s02) / 2.0) * ang2 );
             }
@@ -612,7 +614,6 @@ static void MeanAndGaussian(MeshType & m)
     static void PrincipalDirectionsNormalCycle(MeshType & m){
       tri::RequireVFAdjacency(m);
       tri::RequireFFAdjacency(m);
-      tri::RequirePerFaceNormal(m);
 
         typename MeshType::VertexIterator vi;
 
@@ -629,8 +630,8 @@ static void MeanAndGaussian(MeshType & m)
                     Point3<ScalarType> normalized_edge = p.F()->V(p.F()->Next(p.VInd()))->cP() - (*vi).P();
                     ScalarType edge_length = normalized_edge.Norm();
                     normalized_edge/=edge_length;
-                    Point3<ScalarType> n1 = p.F()->cN();n1.Normalize();
-                    Point3<ScalarType> n2 = p.FFlip()->cN();n2.Normalize();
+                    Point3<ScalarType> n1 = NormalizedTriangleNormal(*(p.F()));
+                    Point3<ScalarType> n2 = NormalizedTriangleNormal(*(p.FFlip()));
                     ScalarType n1n2 = (n1 ^ n2).dot(normalized_edge);
                     n1n2 = std::max(std::min( ScalarType(1.0),n1n2),ScalarType(-1.0));
                     ScalarType beta = math::Asin(n1n2);