WIP: Directly create Manifold from PolySet before attempting repair

src/geometry/manifold/manifoldutils.cc

@@ -106,7 +106,49 @@ template std::shared_ptr<const ManifoldGeometry> createManifoldFromSurfaceMesh(c
 template std::shared_ptr<const ManifoldGeometry> createManifoldFromSurfaceMesh(const CGAL_DoubleMesh &tm);
 #endif
 
+std::unique_ptr<const manifold::Manifold> createManifoldFromTriangularPolySet(const PolySet& ps)
+{
+  assert(ps.isTriangular);
+
+  manifold::Mesh mesh;
+
+  mesh.vertPos.reserve(ps.vertices.size());
+  for (const auto& v : ps.vertices) {
+    mesh.vertPos.emplace_back((float)v.x(), (float)v.y(), (float)v.z());
+  }
+
+  mesh.triVerts.reserve(ps.indices.size());
+  for (const auto& face : ps.indices) {
+    assert(face.size() == 3);
+    mesh.triVerts.emplace_back(face[0], face[1], face[2]);
+  }
+
+  return std::make_unique<manifold::Manifold>(std::move(mesh));
+}
+
 std::shared_ptr<const ManifoldGeometry> createManifoldFromPolySet(const PolySet& ps)
+{
+  // FIXME: To create a Manifold object, we may need to first triangulate.
+  // The incoming PolySet could be severely broken if it originated from user or file input, so
+  // be prepared to repair it.
+  // 1. If it's not triangular, attempt to triangulate it directly
+  // 2. Try to create a Manifold object
+  // 3. If the Manifold object is broken (e.g. not a manifold), attempt repair
+     // 4. If successfully repaired, try to create Manifold again.
+
+  std::unique_ptr<const PolySet> ps_tri;
+  if (!ps.isTriangular) {
+    ps_tri = PolySetUtils::tessellate_faces(ps);
+  }
+  const PolySet good_ps = ps.isTriangular ? ps : *ps_tri;
+  auto mani = createManifoldFromTriangularPolySet(good_ps);
+  if (mani->Status() == Error::NoError) {    
+    return std::make_shared<const ManifoldGeometry>(std::shared_ptr<const manifold::Manifold>(std::move(mani)));
+  }
+
+  LOG("Warning: [manifold] Surface_mesh -> Manifold conversion failed: %1$s", 
+      ManifoldUtils::statusToString(mani->Status()));
+
 {
 #ifdef ENABLE_CGAL
   PolySet psq(ps);
@@ -146,6 +188,7 @@ std::shared_ptr<const ManifoldGeometry> createManifoldFromPolySet(const PolySet&
   return std::make_shared<ManifoldGeometry>();
 #endif
 }
+}
 
 std::shared_ptr<const ManifoldGeometry> createManifoldFromGeometry(const std::shared_ptr<const Geometry>& geom) {
   if (auto mani = std::dynamic_pointer_cast<const ManifoldGeometry>(geom)) {