From 98b779db16492e076dc1cfc9a863121aeafdd800 Mon Sep 17 00:00:00 2001
From: "T.Alderighi" <thomasalderighi@gmail.com>
Date: Thu, 10 May 2018 16:02:26 +0200
Subject: [PATCH] seed tetfuse + tetra3 utility functions

---
 .../algorithms/tetra/tetfuse_collapse.h       | 20 +++++++++
 vcg/space/tetra3.h                            | 44 +++++++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 vcg/complex/algorithms/tetra/tetfuse_collapse.h

diff --git a/vcg/complex/algorithms/tetra/tetfuse_collapse.h b/vcg/complex/algorithms/tetra/tetfuse_collapse.h
new file mode 100644
index 00000000..c8df69c5
--- /dev/null
+++ b/vcg/complex/algorithms/tetra/tetfuse_collapse.h
@@ -0,0 +1,20 @@
+#ifndef VCG_TETFUSECOLLAPSE_H
+#define VCG_TETFUSECOLLAPSE_H
+
+namespace vcg {
+namespace tetra {
+
+template < class TetraMesh >
+class TetFuser {
+    typedef typename TetraMesh::VertexType VertexType;
+    typedef typename TetraMesh::TetraType   TetraType;
+    typedef typename TetraMesh::CoordType   CoordType;
+    typedef typename TetraMesh::ScalarType ScalarType;
+
+    
+};
+
+}
+}
+
+#endif
\ No newline at end of file
diff --git a/vcg/space/tetra3.h b/vcg/space/tetra3.h
index 8f0779c0..3aaa4db5 100644
--- a/vcg/space/tetra3.h
+++ b/vcg/space/tetra3.h
@@ -319,6 +319,50 @@ static Point3<typename TetraType::ScalarType> Normal( const TetraType &t,const i
   return(((t.cP(Tetra::VofF(face,1))-t.cP(Tetra::VofF(face,0)))^(t.cP(Tetra::VofF(face,2))-t.cP(Tetra::VofF(face,0)))).Normalize());
 }
 
+template < class TetraType >
+static typename TetraType::ScalarType DihedralAngle (const TetraType & t, const size_t eidx)
+{
+	typedef typename TetraType::CoordType CoordType;
+	//get two faces incident on eidx
+	int f0 = Tetra::FofE(eidx, 0);
+	int f1 = Tetra::FofE(eidx, 1);
+
+	CoordType p0 = t.P(Tetra::VofF(f0, 0));
+	CoordType p1 = t.P(Tetra::VofF(f0, 1));
+	CoordType p2 = t.P(Tetra::VofF(f0, 2));
+
+	CoordType n0 = ((p2 - p0) ^ (p1 - p0)).normalized();
+
+	p0 = t.P(Tetra::VofF(f1, 0));
+	p1 = t.P(Tetra::VofF(f1, 1));
+	p2 = t.P(Tetra::VofF(f1, 2));
+
+	CoordType n1 = ((p2 - p0) ^ (p1 - p0)).normalized();
+
+	return M_PI - double(acos(n0 * n1));
+
+};
+
+template < class TetraType >
+static typename TetraType::ScalarType SolidAngle (const TetraType & t, const size_t vidx)
+{
+	TetraType::ScalarType a0 = DihedralAngle(t, Tetra::EofV(vidx, 0));
+	TetraType::ScalarType a1 = DihedralAngle(t, Tetra::EofV(vidx, 1));
+	TetraType::ScalarType a2 = DihedralAngle(t, Tetra::EofV(vidx, 2));
+
+	return (a0 + a1 + a2) - M_PI;
+};
+
+template < class TetraType >
+static typename TetraType::ScalarType AspectRatio (const TetraType & t)
+{
+	TetraType::ScalarType a0 = SolidAngle(t, 0);
+	TetraType::ScalarType a1 = SolidAngle(t, 1);
+	TetraType::ScalarType a2 = SolidAngle(t, 2);
+	TetraType::ScalarType a3 = SolidAngle(t, 3);
+
+	return std::min(a0, std::min(a1, std::min(a2, a3)));
+}
 };
 
 /**