Fixed a bug with LeafManager construction from a single level RootNode

Signed-off-by: Nick Avramoussis <4256455+Idclip@users.noreply.github.com>

Author: Idclip

openvdb/openvdb/tree/LeafManager.h

@@ -586,7 +586,12 @@ class LeafManager
         using LeafParentT = typename CopyConstness<TreeType, NonConstLeafParentT>::Type;
 
         std::deque<LeafParentT*> leafParents;
-        mTree->getNodes(leafParents);
+        if constexpr(std::is_same<NonConstLeafParentT, RootNodeType>::value) {
+            leafParents.emplace_back(&mTree->root());
+        }
+        else {
+            mTree->getNodes(leafParents);
+        }
 
         // Compute the leaf counts for each node
 

openvdb/openvdb/tree/Tree.h

@@ -576,8 +576,8 @@ class Tree: public TreeBase
     /// array.reserve(tree.leafCount());//this is a fast preallocation.
     /// tree.getNodes(array);
     /// @endcode
-    template<typename ArrayT> void getNodes(ArrayT& array) { mRoot.getNodes(array); }
-    template<typename ArrayT> void getNodes(ArrayT& array) const { mRoot.getNodes(array); }
+    template<typename ArrayT> void getNodes(ArrayT& array);
+    template<typename ArrayT> void getNodes(ArrayT& array) const;
     //@}
 
     /// @brief Steals all nodes of a certain type from the tree and
@@ -1273,6 +1273,30 @@ Tree<RootNodeType>::writeBuffers(std::ostream &os, bool saveFloatAsHalf) const
 }
 
 
+template<typename RootNodeType>
+template<typename ArrayT>
+inline void
+Tree<RootNodeType>::getNodes(ArrayT& array)
+{
+    using NodeT = typename std::remove_pointer<typename ArrayT::value_type>::type;
+    static_assert(!std::is_same<NodeT, RootNodeType>::value,
+        "getNodes() does not work for the RootNode. Use Tree::root()");
+    mRoot.getNodes(array);
+}
+
+
+template<typename RootNodeType>
+template<typename ArrayT>
+inline void
+Tree<RootNodeType>::getNodes(ArrayT& array) const
+{
+    using NodeT = typename std::remove_pointer<typename ArrayT::value_type>::type;
+    static_assert(!std::is_same<NodeT, const RootNodeType>::value,
+        "getNodes() does not work for the RootNode. Use Tree::root()");
+    mRoot.getNodes(array);
+}
+
+
 template<typename RootNodeType>
 inline void
 Tree<RootNodeType>::clear()

openvdb/openvdb/unittest/TestLeafManager.cc

@@ -323,18 +323,21 @@ TEST_F(TestLeafManager, testTreeConfigurations)
         using TreeType = typename std::decay<decltype(tree)>::type;
         using LeafNodeType = typename TreeType::LeafNodeType;
         using LeafManagerT = openvdb::tree::LeafManager<TreeType>;
+        using ConstLeafManagerT = openvdb::tree::LeafManager<const TreeType>;
 
-        // Add 20 leaf nodes and make sure they are parsed correctly
-        constexpr int64_t Count = 20;
-        std::array<LeafNodeType*, Count> ptrs;
+        // Add 20 leaf nodes and make sure they are constructed correctly
+        constexpr openvdb::Int32 Count = 20;
 
-        const int64_t start = -(Count/2)*LeafNodeType::DIM;
-        const int64_t end   =  (Count/2)*LeafNodeType::DIM;
-        for (int64_t idx = start; idx < end; idx+=LeafNodeType::DIM) {
-            ptrs[idx] = tree.touchLeaf(openvdb::math::Coord(idx));
+        const openvdb::Int32 start = -(Count/2)*openvdb::Int32(LeafNodeType::DIM);
+        const openvdb::Int32 end   =  (Count/2)*openvdb::Int32(LeafNodeType::DIM);
+        for (openvdb::Int32 idx = start; idx < end; idx+=openvdb::Int32(LeafNodeType::DIM)) {
+            tree.touchLeaf(openvdb::math::Coord(idx));
         }
+
         EXPECT_EQ(tree.leafCount(), Count);
         LeafManagerT manager(tree);
         EXPECT_EQ(manager.leafCount(), Count);
+        ConstLeafManagerT cmanager(tree);
+        EXPECT_EQ(cmanager.leafCount(), Count);
     });
 }

pendingchanges/leafmanager_root_fix.txt

@@ -0,0 +1,7 @@
+OpenVDB:
+ - Bug Fixes:
+    - Fixed a bug with LeafManager which wouldn't correctly
+    initialize its LeafNode array for single level Tree configurations
+    i.e. RootNode<LeafNode> (bug introduced in 7.2.0)
+    [Reported by @lanwatch]
+