add Normals to meshes

src/Math/QuadMesh.cpp

@@ -60,5 +60,18 @@ void QuadMesh::AddQuad(const Vector4i &id)
     this->m_Quads.push_back(id);
 }
 
+Vector3f QuadMesh::GetNormal(const Id_t id) const
+{
+    const Vector4i &quad = m_Quads.at(id);
+    const Vector3f &v0 = m_Points.at(quad(0));
+    const Vector3f &v1 = m_Points.at(quad(1));
+    const Vector3f &v3 = m_Points.at(quad(3));
+    
+    Vector3f edge1 = v1 - v0;
+    Vector3f edge2 = v3 - v0;
+    
+    return edge1.cross(edge2).normalized();
+}
+
 
 }

src/Math/QuadMesh.h

@@ -45,6 +45,9 @@ public:
     inline std::vector<Vector3f> & Points() { return this->m_Points; }
     inline std::vector<Vector4i> & Quads() { return this->m_Quads; }
 
+    const Vector4i & GetQuad(const Id_t id) const { return m_Quads.at(id); }
+    Vector3f GetNormal(const Id_t id) const;
+
 private:
     std::vector<Vector3f> m_Points;
     std::vector<Vector4i> m_Quads;

src/Math/TriangleMesh.cpp

@@ -24,8 +24,6 @@
 //////////////////////////////////////////////////////////////////////////////*/
 
 
-
-
 #include "TriangleMesh.h"
 
 
@@ -65,5 +63,18 @@ void TriangleMesh::AddTriangle(const Vector3i &id)
     this->m_Triangles.push_back(id);
 }
 
+Vector3f TriangleMesh::GetNormal(const Id_t id) const
+{
+    const Vector3i &trg = m_Triangles.at(id);
+    const Vector3f &v0 = m_Points.at(trg(0));
+    const Vector3f &v1 = m_Points.at(trg(1));
+    const Vector3f &v2 = m_Points.at(trg(2));
+    
+    Vector3f edge1 = v1 - v0;
+    Vector3f edge2 = v2 - v0;
+    
+    return edge1.cross(edge2).normalized();
+}
+
 
 }

src/Math/TriangleMesh.h

@@ -47,6 +47,9 @@ public:
     inline std::vector<Vector3f> & Points() { return this->m_Points; }
     inline std::vector<Vector3i> & Triangles() { return this->m_Triangles; }
 
+    const Vector3i & GetTriangle(const Id_t id) const { return m_Triangles.at(id); }
+    Vector3f GetNormal(const Id_t id) const;
+
 private:
     std::vector<Vector3f> m_Points;
     std::vector<Vector3i> m_Triangles;