Merge pull request #422 from yungyuc/multidim-rectangle-2dmesh

Add 2D unstructured mesh of triangle elements in a rectangle

cpp/modmesh/view/RManager.cpp

@@ -259,6 +259,10 @@ void RManager::setUpMenu()
         QString("Sample: mesh of \"solvcon\" text in 2D"),
         QString("Create a sample mesh drawing a text string of \"solvcon\""),
         QString("modmesh.gui.sample_mesh.mesh_solvcon_2dtext")));
+    m_meshMenu->addAction(new RPythonAction(
+        QString("Sample: 2D mesh in a rectangle"),
+        QString("Triangular mesh in a rectangle"),
+        QString("modmesh.gui.sample_mesh.mesh_rectangle")));
     m_meshMenu->addAction(new RPythonAction(
         QString("Sample: 3D mesh of mixed elements"),
         QString("Create a very simple sample mesh of mixed elements in 3D"),

modmesh/gui/sample_mesh.py

@@ -29,6 +29,9 @@
 Show example meshes.
 """
 
+import os
+
+import modmesh as mm
 from .. import core
 from .. import view
 
@@ -201,4 +204,25 @@ def mesh_3dmix():
     w_3dmix.showMark()
     view.mgr.pycon.writeToHistory(f"3dmix nedge: {mh.nedge}\n")
 
+
+def mesh_rectangle():
+    fn = os.path.join(os.path.dirname(mm.__file__), '..')
+    fn = os.path.abspath(fn)
+    fn = os.path.join(fn, "tests", "data", "rectangle.msh")
+    if not os.path.exists(fn):
+        view.mgr.pycon.writeToHistory(f"{fn} does not exist\n")
+        return
+
+    with open(fn, 'rb') as fobj:
+        data = fobj.read()
+    view.mgr.pycon.writeToHistory(f"gmsh mesh file {fn} is read\n")
+    gmsh = mm.Gmsh(data)
+    mh = gmsh.to_block()
+    view.mgr.pycon.writeToHistory("StaticMesh object created from gmsh\n")
+    # Open a sub window for triangles and quadrilaterals:
+    w = view.mgr.add3DWidget()
+    w.updateMesh(mh)
+    w.showMark()
+    view.mgr.pycon.writeToHistory(f"nedge: {mh.nedge}\n")
+
 # vim: set ff=unix fenc=utf8 et sw=4 ts=4 sts=4:

tests/data/rectangle.geo

@@ -0,0 +1,27 @@
+/*
+ * A Gmsh template file for a rectangle domain.
+ */
+lc = 0.25;
+// vertices.
+Point(1) = {0,0,0,lc};
+Point(2) = {4,0,0,lc};
+Point(3) = {4,1,0,lc};
+Point(4) = {0,1,0,lc};
+// lines.
+Line(1) = {1,2};
+Line(2) = {2,3};
+Line(3) = {3,4};
+Line(4) = {4,1};
+// surface.
+Line Loop(1) = {1,2,3,4};
+Plane Surface(1) = {1};
+// physics.
+Physical Line("lower") = {1};
+Physical Line("right") = {2};
+Physical Line("upper") = {3};
+Physical Line("left") = {4};
+Physical Surface("domain") = {1};
+// mesh
+Mesh.MshFileVersion = 2.2;
+Mesh.ALgorithm = 6; // Frontal-Delaunay for 2D mesh.
+Mesh 2;