Mesh: extend API to access edges of a facet via Python

src/Mod/Mesh/App/AppMesh.cpp

@@ -33,6 +33,7 @@
 #include "Mesh.h"
 #include "MeshPy.h"
 #include "MeshPointPy.h"
+#include "EdgePy.h"
 #include "FacetPy.h"
 #include "MeshFeaturePy.h"
 #include "FeatureMeshImport.h"
@@ -66,6 +67,7 @@ PyMOD_INIT_FUNC(Mesh)
 
     // add mesh elements
     Base::Interpreter().addType(&Mesh::MeshPointPy  ::Type,meshModule,"MeshPoint");
+    Base::Interpreter().addType(&Mesh::EdgePy       ::Type,meshModule,"Edge");
     Base::Interpreter().addType(&Mesh::FacetPy      ::Type,meshModule,"Facet");
     Base::Interpreter().addType(&Mesh::MeshPy       ::Type,meshModule,"Mesh");
     Base::Interpreter().addType(&Mesh::MeshFeaturePy::Type,meshModule,"Feature");

src/Mod/Mesh/App/CMakeLists.txt

@@ -28,12 +28,14 @@ if (BUILD_QT5)
     )
 endif()
 
+generate_from_xml(EdgePy)
 generate_from_xml(FacetPy)
 generate_from_xml(MeshFeaturePy)
 generate_from_xml(MeshPointPy)
 generate_from_xml(MeshPy)
 
 SET(Mesh_XML_SRCS
+    EdgePy.xml
     FacetPy.xml
     MeshFeaturePy.xml
     MeshPointPy.xml
@@ -331,6 +333,9 @@ SET(Mesh_SRCS
     Exporter.h
     Importer.cpp
     Importer.h
+    Edge.cpp
+    Edge.h
+    EdgePyImp.cpp
     Facet.cpp
     Facet.h
     FacetPyImp.cpp

src/Mod/Mesh/App/Core/Elements.cpp

@@ -280,6 +280,25 @@ bool MeshGeomEdge::IntersectWithLine (const Base::Vector3f &rclPt,
     return dist2 + dist3 <= dist1 + eps;
 }
 
+bool MeshGeomEdge::IsParallel(const MeshGeomEdge &edge) const
+{
+    Base::Vector3f r(_aclPoints[1] - _aclPoints[0]);
+    Base::Vector3f s(edge._aclPoints[1] - edge._aclPoints[0]);
+    Base::Vector3f n = r.Cross(s);
+    return n.IsNull();
+}
+
+bool MeshGeomEdge::IsCollinear(const MeshGeomEdge &edge) const
+{
+    if (IsParallel(edge)) {
+        Base::Vector3f r(_aclPoints[1] - _aclPoints[0]);
+        Base::Vector3f d = edge._aclPoints[0] - _aclPoints[0];
+        return d.Cross(r).IsNull();
+    }
+
+    return false;
+}
+
 bool MeshGeomEdge::IntersectWithEdge (const MeshGeomEdge &edge, Base::Vector3f &res) const
 {
     const float eps = 1e-06f;

src/Mod/Mesh/App/Core/Elements.h

@@ -198,6 +198,16 @@ class MeshExport MeshGeomEdge
    * Checks if the projection point of \a point lies on the edge.
    */
   bool IsProjectionPointOf(const Base::Vector3f& point) const;
+  /**
+   * Checks if the two edges are parallel.
+   * \note Parallel edges could be collinear.
+   */
+  bool IsParallel(const MeshGeomEdge &edge) const;
+  /**
+   * Checks if the two edges are collinear.
+   * \note Collinear edges always are parallel.
+   */
+  bool IsCollinear(const MeshGeomEdge &edge) const;
 
 public:
   Base::Vector3f _aclPoints[2];  /**< Corner points */

src/Mod/Mesh/App/Core/tritritest.h

@@ -41,7 +41,7 @@ OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
 */
 
 
-#include <math.h>
+#include <cmath>
 
 #define FABS(x) ((float)fabs(x))        /* implement as is fastest on your machine */
 

src/Mod/Mesh/App/Edge.cpp

@@ -0,0 +1,74 @@
+/***************************************************************************
+ *   Copyright (c) 2021 Werner Mayer <wmayer[at]users.sourceforge.net>     *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  is distributed in the hope that it will be useful,      *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 51 Franklin Street,      *
+ *   Fifth Floor, Boston, MA  02110-1301, USA                              *
+ *                                                                         *
+ ***************************************************************************/
+
+
+#include "PreCompiled.h"
+#ifndef _PreComp_
+# include <sstream>
+#endif
+
+#include "Edge.h"
+#include "Mesh.h"
+
+using namespace Mesh;
+
+Edge::Edge()
+  : Index(-1)
+  , Mesh(nullptr)
+{
+    for (int i=0; i<2; i++) {
+        PIndex[i] = MeshCore::POINT_INDEX_MAX;
+        NIndex[i] = MeshCore::FACET_INDEX_MAX;
+    }
+}
+
+Edge::Edge(const Edge& e)
+  : MeshCore::MeshGeomEdge(e)
+  , Index(e.Index)
+  , Mesh(e.Mesh)
+{
+    for (int i=0; i<2; i++) {
+        PIndex[i] = e.PIndex[i];
+        NIndex[i] = e.NIndex[i];
+    }
+}
+
+Edge::~Edge()
+{
+}
+
+void Edge::operator = (const Edge& e)
+{
+    MeshCore::MeshGeomEdge::operator = (e);
+    Mesh  = e.Mesh;
+    Index = e.Index;
+    for (int i=0; i<2; i++) {
+        PIndex[i] = e.PIndex[i];
+        NIndex[i] = e.NIndex[i];
+    }
+}
+
+void Edge::unbound()
+{
+    Index = -1;
+    Mesh = nullptr;
+}

src/Mod/Mesh/App/Edge.h

@@ -0,0 +1,63 @@
+/***************************************************************************
+ *   Copyright (c) 2021 Werner Mayer <wmayer[at]users.sourceforge.net>     *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  is distributed in the hope that it will be useful,      *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 51 Franklin Street,      *
+ *   Fifth Floor, Boston, MA  02110-1301, USA                              *
+ *                                                                         *
+ ***************************************************************************/
+
+
+#ifndef MESH_EDGE_H
+#define MESH_EDGE_H
+
+#include <Base/Matrix.h>
+#include <Base/Vector3D.h>
+#include <Base/Handle.h>
+
+#include <Mod/Mesh/App/Core/Elements.h>
+
+namespace Mesh
+{
+// forward declaration
+class MeshObject;
+
+/** The Edge helper class
+ * The Edge class provides an interface for the EdgePy class for
+ * convenient access to the Mesh data structure. This class should not be used
+ * for programming algorithms in C++. Use Mesh Core classes instead!
+ */
+class MeshExport Edge : public MeshCore::MeshGeomEdge
+{
+public:
+    Edge();
+    Edge(const Edge& f);
+    ~Edge();
+
+    bool isBound() const {return Index != -1;}
+    void unbound();
+    void operator = (const Edge& f);
+
+    int Index;
+    MeshCore::PointIndex PIndex[2];
+    MeshCore::FacetIndex NIndex[2];
+    Base::Reference<MeshObject> Mesh;
+};
+
+} // namespace Mesh
+
+
+#endif // MESH_EDGE_H

src/Mod/Mesh/App/EdgePy.xml

@@ -0,0 +1,90 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<GenerateModel xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="generateMetaModel_Module.xsd">
+  <PythonExport
+      Father="PyObjectBase"
+      Name="EdgePy"
+      Twin="Edge"
+      TwinPointer="Edge"
+      Include="Mod/Mesh/App/Edge.h"
+      FatherInclude="Base/PyObjectBase.h"
+      Namespace="Mesh"
+      Constructor="true"
+      Delete="true"
+      FatherNamespace="Base">
+    <Documentation>
+      <Author Licence="LGPL" Name="Werner Mayer" EMail="wmayer[at]users.sourceforge.net" />
+        <DeveloperDocu>Edge in a Mesh</DeveloperDocu>
+        <UserDocu>Edge in mesh
+This is an edge of a facet in a MeshObject. You can get it by e.g. iterating over the facets of a
+mesh and calling getEdge(index).
+        </UserDocu>
+    </Documentation>
+    <Methode Name="intersectWithEdge">
+          <Documentation>
+              <UserDocu>intersectWithEdge(Edge) -> list
+Get a list of intersection points with another edge.
+              </UserDocu>
+          </Documentation>
+    </Methode>
+    <Methode Name="isParallel">
+          <Documentation>
+              <UserDocu>isParallel(Edge) -> bool
+Checks if the two edges are parallel.
+              </UserDocu>
+          </Documentation>
+    </Methode>
+    <Methode Name="isCollinear">
+          <Documentation>
+              <UserDocu>isCollinear(Edge) -> bool
+Checks if the two edges are collinear.
+              </UserDocu>
+          </Documentation>
+    </Methode>
+    <Methode Name="unbound">
+        <Documentation>
+            <UserDocu>method unbound()
+Cut the connection to a MeshObject. The edge becomes
+free and is more or less a simple edge.
+After calling unbound() no topological operation will
+work!
+            </UserDocu>
+        </Documentation>
+    </Methode>
+    <Attribute Name="Index" ReadOnly="true">
+          <Documentation>
+              <UserDocu>The index of this edge of the facet</UserDocu>
+          </Documentation>
+          <Parameter Name="Index" Type="Long"/>
+    </Attribute>
+    <Attribute Name="Points" ReadOnly="true">
+          <Documentation>
+              <UserDocu>A list of points of the edge</UserDocu>
+          </Documentation>
+          <Parameter Name="Points" Type="List"/>
+    </Attribute>
+    <Attribute Name="PointIndices" ReadOnly="true">
+          <Documentation>
+              <UserDocu>The index tuple of point vertices of the mesh this edge is built of</UserDocu>
+          </Documentation>
+          <Parameter Name="PointIndices" Type="Tuple"/>
+    </Attribute>
+    <Attribute Name="NeighbourIndices" ReadOnly="true">
+            <Documentation>
+                <UserDocu>The index tuple of neighbour facets of the mesh this edge is adjacent with</UserDocu>
+            </Documentation>
+            <Parameter Name="NeighbourIndices" Type="Tuple"/>
+    </Attribute>
+    <Attribute Name="Length" ReadOnly="true">
+            <Documentation>
+                <UserDocu>The length of the edge</UserDocu>
+            </Documentation>
+            <Parameter Name="Length" Type="Float"/>
+    </Attribute>
+    <Attribute Name="Bound" ReadOnly="true">
+        <Documentation>
+            <UserDocu>Bound state of the edge</UserDocu>
+        </Documentation>
+        <Parameter Name="Bound" Type="Boolean"/>
+    </Attribute>
+  </PythonExport>
+</GenerateModel>