Return std::optional to indicate mesh AABB cannot be computed

* Also fix `_sdfMesh` to be `const &`

Signed-off-by: Gabriel Pacheco <[email protected]>

Author: gabrielfpacheco

include/gz/sim/Util.hh

@@ -339,8 +339,8 @@ namespace gz
     /// \brief Compute the axis-aligned bounding box of a mesh.
     /// \param _sdfMesh Mesh SDF DOM.
     /// \return The AABB of the mesh in its local frame.
-    GZ_SIM_VISIBLE math::AxisAlignedBox meshAxisAlignedBox(
-      const sdf::Mesh _sdfMesh);
+    GZ_SIM_VISIBLE std::optional<math::AxisAlignedBox> meshAxisAlignedBox(
+      const sdf::Mesh &_sdfMesh);
 
     /// \brief Environment variable holding resource paths.
     const std::string kResourcePathEnv{"GZ_SIM_RESOURCE_PATH"};

src/Util.cc

@@ -989,15 +989,16 @@ const common::Mesh *optimizeMesh(const sdf::Mesh &_meshSdf,
   return optimizedMesh;
 }
 
-math::AxisAlignedBox meshAxisAlignedBox(sdf::Mesh _sdfMesh)
+std::optional<math::AxisAlignedBox> meshAxisAlignedBox(
+  const sdf::Mesh &_sdfMesh)
 {
   auto mesh = loadMesh(_sdfMesh);
   if (!mesh)
   {
-    gzwarn << "Mesh could not be loaded. Invalidating its bounding box."
+    gzwarn << "Mesh could not be loaded. Bounding box cannot be computed."
            << std::endl;
 
-    return math::AxisAlignedBox();
+    return std::nullopt;
   }
 
   // Get the mesh's bounding box

src/Util_TEST.cc

@@ -1052,14 +1052,14 @@ TEST_F(UtilTest, MeshAxisAlignedBoundingBox)
 {
   sdf::Mesh meshSdf;
   math::AxisAlignedBox emptyBox, aab;
-  EXPECT_EQ(emptyBox, meshAxisAlignedBox(meshSdf));
+  EXPECT_FALSE(meshAxisAlignedBox(meshSdf).has_value());
 
   meshSdf.SetUri("invalid_uri");
   meshSdf.SetFilePath("invalid_filepath");
-  EXPECT_EQ(emptyBox, meshAxisAlignedBox(meshSdf));
+  EXPECT_FALSE(meshAxisAlignedBox(meshSdf).has_value());
 
   meshSdf.SetUri("name://unit_box");
-  aab = meshAxisAlignedBox(meshSdf);
+  aab = meshAxisAlignedBox(meshSdf).value();
   EXPECT_NE(emptyBox, aab);
   EXPECT_EQ(aab.Size(), math::Vector3d::One);
   EXPECT_EQ(aab.Min(), math::Vector3d(-0.5, -0.5, -0.5));
@@ -1068,7 +1068,7 @@ TEST_F(UtilTest, MeshAxisAlignedBoundingBox)
 
   // Validate scaling using the unit box mesh
   meshSdf.SetScale(math::Vector3d(2, 3, 4));
-  aab = meshAxisAlignedBox(meshSdf);
+  aab = meshAxisAlignedBox(meshSdf).value();
   EXPECT_NE(emptyBox, aab);
   EXPECT_EQ(aab.Size(), math::Vector3d(2, 3, 4));
   EXPECT_EQ(aab.Min(), math::Vector3d(-1, -1.5, -2));
@@ -1080,7 +1080,7 @@ TEST_F(UtilTest, MeshAxisAlignedBoundingBox)
   std::string filePath = common::joinPaths(std::string(PROJECT_SOURCE_PATH),
     "test", "media", "duck.dae");
   meshSdf.SetFilePath(filePath);
-  aab = meshAxisAlignedBox(meshSdf);
+  aab = meshAxisAlignedBox(meshSdf).value();
   EXPECT_NE(emptyBox, aab);
 
   // Expected values obtained from the mesh file using Blender: