Add tools::activeVoxelCount()

Signed-off-by: Dan Bailey <danbailey@ilm.com>

openvdb/openvdb/CMakeLists.txt

@@ -295,6 +295,7 @@ set(OPENVDB_LIBRARY_TOOLS_INCLUDE_FILES
   tools/ChangeBackground.h
   tools/Clip.h
   tools/Composite.h
+  tools/Count.h
   tools/Dense.h
   tools/DenseSparseTools.h
   tools/Diagnostics.h

openvdb/openvdb/tools/Count.h

@@ -0,0 +1,83 @@
+// Copyright Contributors to the OpenVDB Project
+// SPDX-License-Identifier: MPL-2.0
+//
+/// @file   Count.h
+///
+/// @brief Functions to count tiles, nodes or voxels in a grid
+///
+/// @author Dan Bailey
+///
+
+#ifndef OPENVDB_TOOLS_COUNT_HAS_BEEN_INCLUDED
+#define OPENVDB_TOOLS_COUNT_HAS_BEEN_INCLUDED
+
+#include <openvdb/version.h>
+#include <openvdb/tree/NodeManager.h>
+
+namespace openvdb {
+OPENVDB_USE_VERSION_NAMESPACE
+namespace OPENVDB_VERSION_NAME {
+namespace tools {
+
+
+/// @brief Return the total number of active voxels in the tree.
+template <typename TreeT>
+Index64 activeVoxelCount(const TreeT& tree, bool threaded = true);
+
+
+////////////////////////////////////////
+
+
+namespace count_internal {
+
+template<typename TreeType>
+struct ActiveVoxelCountOp
+{
+    using LeafT = typename TreeType::LeafNodeType;
+
+    ActiveVoxelCountOp() = default;
+    ActiveVoxelCountOp(const ActiveVoxelCountOp&, tbb::split) { }
+
+    template<typename NodeT>
+    bool operator()(const NodeT& node, size_t)
+    {
+        for (auto iter = node.cbeginValueOn(); iter; ++iter) {
+            count += NodeT::ChildNodeType::NUM_VOXELS;
+        }
+        return true;
+    }
+
+    bool operator()(const LeafT& leaf, size_t)
+    {
+        count += leaf.onVoxelCount();
+        return false;
+    }
+
+    void join(const ActiveVoxelCountOp& other)
+    {
+        count += other.count;
+    }
+
+    openvdb::Index64 count{0};
+};
+
+} // namespace count_internal
+
+
+////////////////////////////////////////
+
+
+template <typename TreeT>
+Index64 activeVoxelCount(const TreeT& tree, bool threaded)
+{
+    count_internal::ActiveVoxelCountOp<TreeT> op;
+    tree::DynamicNodeManager<const TreeT> nodeManager(tree);
+    nodeManager.reduceTopDown(op, threaded);
+    return op.count;
+}
+
+} // namespace tools
+} // namespace OPENVDB_VERSION_NAME
+} // namespace openvdb
+
+#endif // OPENVDB_TOOLS_COUNT_HAS_BEEN_INCLUDED

openvdb/openvdb/unittest/CMakeLists.txt

@@ -62,6 +62,7 @@ set(UNITTEST_SOURCE_FILES
   TestClip.cc
   TestConjGradient.cc
   TestCoord.cc
+  TestCount.cc
   TestCpt.cc
   TestCurl.cc
   TestDelayedLoadMetadata.cc

openvdb/openvdb/unittest/TestCount.cc

@@ -0,0 +1,30 @@
+// Copyright Contributors to the OpenVDB Project
+// SPDX-License-Identifier: MPL-2.0
+
+#include "gtest/gtest.h"
+
+#include <openvdb/openvdb.h>
+#include <openvdb/tools/Count.h>
+#include <openvdb/tools/LevelSetSphere.h>
+
+
+class TestCount: public ::testing::Test
+{
+};
+
+
+////////////////////////////////////////
+
+
+TEST_F(TestCount, testActiveVoxelCount)
+{
+    using namespace openvdb;
+
+    auto grid = tools::createLevelSetSphere<FloatGrid>(10.0f, Vec3f(0), 0.1f);
+
+    Index64 activeVoxelCount1 = grid->tree().activeVoxelCount();
+
+    Index64 activeVoxelCount2 = tools::activeVoxelCount(grid->tree());
+
+    EXPECT_EQ(activeVoxelCount1, activeVoxelCount2);
+}