[geometry] Strengthen VTK to volume mesh error cases (RobotLocomotion…

…#20240)

Add some slightly more adversarial VTK files to the test suite, and improve
error reporting for VTK parse failures.

geometry/BUILD.bazel

@@ -629,10 +629,14 @@ filegroup(
     name = "test_vtk_files",
     testonly = 1,
     srcs = [
+        "test/bad_tet.vtk",
+        "test/cube_as_6_squares.vtk",
         "test/non_convex_mesh.vtk",
         "test/one_negative_tetrahedron.vtk",
         "test/one_tetrahedron.vtk",
+        "test/some_volume.vtk",
         "test/two_tetrahedra_with_field_variable.vtk",
+        "test/unstructured.vtk",
     ],
 )
 

geometry/proximity/test/vtk_to_volume_mesh_test.cc

@@ -58,24 +58,54 @@ GTEST_TEST(VtkToVolumeMeshTest, BadScale) {
   const double kNegativeScale = -0.01;
   DRAKE_EXPECT_THROWS_MESSAGE(
       internal::ReadVtkToVolumeMesh(test_file, kNegativeScale),
-      "ReadVtkToVolumeMesh: scale=.* is not a positive number.*");
+      "ReadVtkToVolumeMesh.*: scale=.* is not a positive number.*");
 
   const double kZeroScale = 0.0;
   DRAKE_EXPECT_THROWS_MESSAGE(
       internal::ReadVtkToVolumeMesh(test_file, kZeroScale),
-      "ReadVtkToVolumeMesh: scale=.* is not a positive number.*");
+      "ReadVtkToVolumeMesh.*: scale=.* is not a positive number.*");
 }
 
 GTEST_TEST(VtkToVolumeMeshTest, BogusFileName) {
   const std::string bogus_filename = "bogus_filename";
-  EXPECT_THROW(internal::ReadVtkToVolumeMesh(bogus_filename), std::exception);
+  DRAKE_EXPECT_THROWS_MESSAGE(internal::ReadVtkToVolumeMesh(bogus_filename),
+                              ".*at least one tetra.*");
 }
 
 GTEST_TEST(VtkToVolumeMeshTest, WrongFileType) {
   const std::string require_vtk_but_this_is_obj =
       FindResourceOrThrow("drake/geometry/test/non_convex_mesh.obj");
-  EXPECT_THROW(internal::ReadVtkToVolumeMesh(require_vtk_but_this_is_obj),
-               std::exception);
+  DRAKE_EXPECT_THROWS_MESSAGE(
+      internal::ReadVtkToVolumeMesh(require_vtk_but_this_is_obj),
+      ".*at least one tetra.*");
+}
+
+GTEST_TEST(VtkToVolumeMeshTest, WrongFileContentsCube) {
+  const std::string cube_vtk =
+      FindResourceOrThrow("drake/geometry/test/cube_as_6_squares.vtk");
+  DRAKE_EXPECT_THROWS_MESSAGE(internal::ReadVtkToVolumeMesh(cube_vtk),
+                              ".*at least one tetra.*");
+}
+
+GTEST_TEST(VtkToVolumeMeshTest, WrongFileContentsVolume) {
+  const std::string volume_vtk =
+      FindResourceOrThrow("drake/geometry/test/some_volume.vtk");
+  DRAKE_EXPECT_THROWS_MESSAGE(internal::ReadVtkToVolumeMesh(volume_vtk),
+                              ".*at least one tetra.*");
+}
+
+GTEST_TEST(VtkToVolumeMeshTest, WrongFileContentsUnstructured) {
+  const std::string unstructured_vtk =
+      FindResourceOrThrow("drake/geometry/test/unstructured.vtk");
+  DRAKE_EXPECT_THROWS_MESSAGE(internal::ReadVtkToVolumeMesh(unstructured_vtk),
+                              ".*non-tetra.*");
+}
+
+GTEST_TEST(VtkToVolumeMeshTest, WrongFileContentsBadTet) {
+  const std::string bad_tet_vtk =
+      FindResourceOrThrow("drake/geometry/test/bad_tet.vtk");
+  DRAKE_EXPECT_THROWS_MESSAGE(internal::ReadVtkToVolumeMesh(bad_tet_vtk),
+                              ".*at least one tetra.*");
 }
 
 }  // namespace

geometry/proximity/vtk_to_volume_mesh.cc

@@ -24,7 +24,8 @@ VolumeMesh<double> ReadVtkToVolumeMesh(const std::string& filename,
                                        double scale) {
   if (scale <= 0.0) {
     throw std::runtime_error(fmt::format(
-        "ReadVtkToVolumeMesh: scale={} is not a positive number", scale));
+        "ReadVtkToVolumeMesh('{}', {}): scale={} is not a positive number",
+        filename, scale, scale));
   }
   vtkNew<vtkUnstructuredGridReader> reader;
   reader->SetFileName(filename.c_str());
@@ -43,9 +44,21 @@ VolumeMesh<double> ReadVtkToVolumeMesh(const std::string& filename,
 
   std::vector<VolumeElement> elements;
   elements.reserve(vtk_mesh->GetNumberOfCells());
-  vtkCellIterator* iter = vtk_mesh->NewCellIterator();
+  auto iter =
+      vtkSmartPointer<vtkCellIterator>::Take(vtk_mesh->NewCellIterator());
   for (iter->InitTraversal(); !iter->IsDoneWithTraversal();
        iter->GoToNextCell()) {
+    if (iter->GetCellType() != VTK_TETRA) {
+      vtkNew<vtkGenericCell> bad_cell;
+      iter->GetCell(bad_cell);
+      auto msg = fmt::format(
+          "ReadVtkToVolumeMesh('{}', {}): file contains a"
+          " non-tetrahedron(type id={}) cell with type id {}, dimension {},"
+          " and number of points {}",
+          filename, scale, static_cast<int>(VTK_TETRA), bad_cell->GetCellType(),
+          bad_cell->GetCellDimension(), bad_cell->GetNumberOfPoints());
+      throw std::runtime_error(msg);
+    }
     vtkIdList* vtk_vertex_ids = iter->GetPointIds();
     // clang-format off
     elements.emplace_back(vtk_vertex_ids->GetId(0),
@@ -54,7 +67,6 @@ VolumeMesh<double> ReadVtkToVolumeMesh(const std::string& filename,
                           vtk_vertex_ids->GetId(3));
     // clang-format on
   }
-  iter->Delete();
 
   return {std::move(elements), std::move(vertices)};
 }

geometry/test/bad_tet.vtk

@@ -0,0 +1,17 @@
+# vtk DataFile Version 2.0
+Example of bad one-tet mesh -- triangle mis-typed as tet
+ASCII
+DATASET UNSTRUCTURED_GRID
+POINTS 3 float
+0.0 0.0 0.0
+1.0 0.0 0.0
+0.0 1.0 0.0
+
+CELLS 1 4
+4 0 1 2
+
+CELL_TYPES 1
+10
+
+
+

geometry/test/cube_as_6_squares.vtk

@@ -0,0 +1,61 @@
+# vtk DataFile Version 2.0
+Cube represented by six squares from https://examples.vtk.org/site/VTKFileFormats/
+ASCII
+DATASET POLYDATA
+POINTS 8 float
+0.0 0.0 0.0
+1.0 0.0 0.0
+1.0 1.0 0.0
+0.0 1.0 0.0
+0.0 0.0 1.0
+1.0 0.0 1.0
+1.0 1.0 1.0
+0.0 1.0 1.0
+POLYGONS 6 30
+4 0 1 2 3
+4 4 5 6 7
+4 0 1 5 4
+4 2 3 7 6
+4 0 4 7 3
+4 1 2 6 5
+CELL_DATA 6
+SCALARS cell_scalars int 1
+LOOKUP_TABLE default
+0
+1
+2
+3
+4
+5
+NORMALS cell_normals float
+0 0 -1
+0 0 1
+0 -1 0
+0 1 0
+-1 0 0
+1 0 0
+FIELD FieldData 2
+cellIds 1 6 int
+0 1 2 3 4 5
+faceAttributes 2 6 float
+0.0 1.0 1.0 2.0 2.0 3.0 3.0 4.0 4.0 5.0 5.0 6.0
+POINT_DATA 8
+SCALARS sample_scalars float 1
+LOOKUP_TABLE my_table
+0.0
+1.0
+2.0
+3.0
+4.0
+5.0
+6.0
+7.0
+LOOKUP_TABLE my_table 8
+0.0 0.0 0.0 1.0
+1.0 0.0 0.0 1.0
+0.0 1.0 0.0 1.0
+1.0 1.0 0.0 1.0
+0.0 0.0 1.0 1.0
+1.0 0.0 1.0 1.0
+0.0 1.0 1.0 1.0
+1.0 1.0 1.0 1.0

geometry/test/some_volume.vtk

@@ -0,0 +1,16 @@
+# vtk DataFile Version 2.0
+Example of scalar field on uniform rectilinear grid from https://examples.vtk.org/site/VTKFileFormats/
+ASCII
+DATASET STRUCTURED_POINTS
+DIMENSIONS 3 4 6
+ASPECT_RATIO 1 1 1
+ORIGIN 0 0 0
+POINT_DATA 72
+SCALARS volume_scalars char 1
+LOOKUP_TABLE default
+0 0 0 0 0 0 0 0 0 0 0 0
+0 5 10 15 20 25 25 20 15 10 5 0
+0 10 20 30 40 50 50 40 30 20 10 0
+0 10 20 30 40 50 50 40 30 20 10 0
+0 5 10 15 20 25 25 20 15 10 5 0
+0 0 0 0 0 0 0 0 0 0 0 0

geometry/test/unstructured.vtk

@@ -0,0 +1,72 @@
+# vtk DataFile Version 2.0
+Example of Unstructured Grid of Many Cell Types from https://examples.vtk.org/site/VTKFileFormats/
+ASCII
+DATASET UNSTRUCTURED_GRID
+
+POINTS 27 float
+0 0 0  1 0 0  2 0 0  0 1 0  1 1 0  2 1 0
+0 0 1  1 0 1  2 0 1  0 1 1  1 1 1  2 1 1
+0 1 2  1 1 2  2 1 2  0 1 3  1 1 3  2 1 3
+0 1 4  1 1 4  2 1 4  0 1 5  1 1 5  2 1 5
+0 1 6  1 1 6  2 1 6
+
+CELLS 11 60
+8 0 1 4 3 6 7 10 9
+8 1 2 4 5 7 8 10 11
+4 6 10 9 12
+4 11 14 10 13
+6 15 16 17 14 13 12
+6 18 15 19 16 20 17
+4 22 23 20 19
+3 21 22 18
+3 22 19 18
+2 26 25
+1 24
+
+CELL_TYPES 11
+12
+11
+10
+8
+7
+6
+9
+5
+4
+3
+1
+
+POINT_DATA 27
+SCALARS scalars float 1
+LOOKUP_TABLE default
+0.0 1.0 2.0 3.0 4.0 5.0
+6.0 7.0 8.0 9.0 10.0 11.0
+12.0 13.0 14.0 15.0 16.0 17.0
+18.0 19.0 20.0 21.0 22.0 23.0
+24.0 25.0 26.0
+
+VECTORS vectors float
+1 0 0  1 1 0  0 2 0  1 0 0  1 1 0  0 2 0
+1 0 0  1 1 0  0 2 0  1 0 0  1 1 0  0 2 0
+0 0 1  0 0 1  0 0 1  0 0 1  0 0 1  0 0 1
+0 0 1  0 0 1  0 0 1  0 0 1  0 0 1  0 0 1
+0 0 1  0 0 1  0 0 1
+
+CELL_DATA 11
+SCALARS scalars float 1
+LOOKUP_TABLE CellColors
+0.0 1.0 2.0 3.0 4.0 5.0
+6.0 7.0 8.0 9.0 10.0
+
+LOOKUP_TABLE CellColors 11
+.4 .4 1 1
+.4 1 .4 1
+.4 1 1 1
+1 .4 .4 1
+1 .4 1 1
+1 1 .4 1
+1 1 1 1
+1 .5 .5 1
+.5 1 .5 1
+.5 .5 .5 1
+1 .5 .4 1