Allow to create empty RecastMesh

apps/openmw_test_suite/detournavigator/recastmeshbuilder.cpp

@@ -31,9 +31,11 @@ namespace
         }
     };
 
-    TEST_F(DetourNavigatorRecastMeshBuilderTest, create_for_empty_should_throw_exception)
+    TEST_F(DetourNavigatorRecastMeshBuilderTest, create_for_empty_should_return_empty)
     {
-        EXPECT_THROW(mBuilder.create(), std::invalid_argument);
+        const auto recastMesh = mBuilder.create();
+        EXPECT_EQ(recastMesh->getVertices(), std::vector<float>());
+        EXPECT_EQ(recastMesh->getIndices(), std::vector<int>());
     }
 
     TEST_F(DetourNavigatorRecastMeshBuilderTest, add_bhv_triangle_mesh_shape)

components/detournavigator/chunkytrimesh.cpp

@@ -120,7 +120,7 @@ namespace DetourNavigator
         const auto trianglesCount = indices.size() / 3;
 
         if (trianglesCount == 0)
-            throw InvalidArgument("ChunkyTriMesh tris should contain at least 3 values");
+            return;
 
         const auto nchunks = (trianglesCount + trisPerChunk - 1) / trisPerChunk;
 

components/detournavigator/makenavmesh.cpp

@@ -269,9 +269,6 @@ namespace DetourNavigator
             getRadius(settings, agentHalfExtents),
             " changedTile=", changedTile);
 
-        const auto& boundsMin = recastMesh.getBoundsMin();
-        const auto& boundsMax = recastMesh.getBoundsMax();
-
         auto& navMesh = navMeshCacheItem.mValue;
         const auto& params = *navMesh.lock()->getParams();
         const osg::Vec3f origin(params.orig[0], params.orig[1], params.orig[2]);
@@ -287,6 +284,15 @@ namespace DetourNavigator
                                                                         nullptr, nullptr));
         }
 
+        const auto& boundsMin = recastMesh.getBoundsMin();
+        const auto& boundsMax = recastMesh.getBoundsMax();
+
+        if (boundsMin == boundsMax)
+        {
+            log("ignore add tile: recastMesh is empty");
+            return;
+        }
+
         const auto tileBounds = makeTileBounds(settings, changedTile);
         const osg::Vec3f tileBorderMin(tileBounds.mMin.x(), boundsMin.y() - 1, tileBounds.mMin.y());
         const osg::Vec3f tileBorderMax(tileBounds.mMax.x(), boundsMax.y() + 1, tileBounds.mMax.y());

components/detournavigator/recastmesh.cpp

@@ -10,6 +10,7 @@ namespace DetourNavigator
         , mVertices(std::move(vertices))
         , mChunkyTriMesh(mVertices, mIndices, settings.mTrianglesPerChunk)
     {
+        if (getVerticesCount())
             rcCalcBounds(mVertices.data(), static_cast<int>(getVerticesCount()), mBoundsMin.ptr(), mBoundsMax.ptr());
     }
 }