From 1a051ec5556f57149259fb1590671e0bd51e9c04 Mon Sep 17 00:00:00 2001
From: Christopher Lackner <clackner@cerbsim.com>
Date: Fri, 16 Oct 2020 12:05:03 +0200
Subject: [PATCH] export Polyhedra to Python and add test case

---
 libsrc/csg/python_csg.cpp | 29 +++++++++++++++++++++++++++++
 tests/pytest/test_csg.py  | 27 +++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 tests/pytest/test_csg.py

diff --git a/libsrc/csg/python_csg.cpp b/libsrc/csg/python_csg.cpp
index 09063e51..0954b2d6 100644
--- a/libsrc/csg/python_csg.cpp
+++ b/libsrc/csg/python_csg.cpp
@@ -354,6 +354,35 @@ When r =1, the truncated elliptic cone becomes an elliptic cylinder.
 When r tends to zero, the truncated elliptic cone tends to a full elliptic cone.
 However, when r = 0, the top part becomes a point(tip) and meshing fails!
 )raw_string");
+
+  m.def("Polyhedron", [](py::list points, py::list faces)
+  {
+    auto poly = new Polyhedra();
+    for(auto p : points)
+      poly->AddPoint(py::cast<Point<3>>(p));
+    int fnr = 0;
+    for(auto face : faces)
+      {
+        auto lface = py::cast<py::list>(face);
+        if(py::len(lface) == 3)
+          poly->AddFace(py::cast<int>(lface[0]),
+                        py::cast<int>(lface[1]),
+                        py::cast<int>(lface[2]),
+                        fnr++);
+        else if(py::len(lface) == 4)
+          {
+            poly->AddFace(py::cast<int>(lface[0]),
+                          py::cast<int>(lface[1]),
+                          py::cast<int>(lface[2]),
+                          fnr);
+            poly->AddFace(py::cast<int>(lface[0]),
+                          py::cast<int>(lface[2]),
+                          py::cast<int>(lface[3]),
+                          fnr++);
+          }
+      }
+    return make_shared<SPSolid>(new Solid(poly));
+  });
   
   m.def ("Or", FunctionPointer([](shared_ptr<SPSolid> s1, shared_ptr<SPSolid> s2)
                                  {
diff --git a/tests/pytest/test_csg.py b/tests/pytest/test_csg.py
new file mode 100644
index 00000000..55adcbbd
--- /dev/null
+++ b/tests/pytest/test_csg.py
@@ -0,0 +1,27 @@
+from netgen.csg import *
+
+def test_2_polyhedra():
+    geo = CSGeometry()
+    first = Polyhedron([(0,0,0), (0,1,0), (3,1,0), (3,0,0),
+                        (0,1,1), (3,1,1), (3,0,1), (0,0,1)],
+                        [(0,1,2,3), (1,4,5,2), (2,5,6,3), (3,6,7,0),
+                         (0,7,4,1), (7,6,5,4)])
+    # TODO: height = 0.1 not working!
+    height = 0.3
+    second = Polyhedron([(0,0,1), (0,1,1), (3,1,1), (3,0,1),
+                         (0,1,1+height), (3,1,1+height),
+                         (3,0,1+height), (0,0,1+height)],
+                        [(0,1,2,3), (1,4,5,2), (2,5,6,3), (3,6,7,0),
+                         (0,7,4,1), (7,6,5,4)])
+
+    geo.Add(first)
+    geo.Add(second)
+    Draw(geo)
+    mesh = geo.GenerateMesh()
+    return mesh
+
+
+if __name__ == "__main__":
+    from ngsolve import Mesh, Draw
+    mesh = Mesh(test_2_polyhedra())
+    Draw(mesh)