source/blender/blenkernel/BKE_attribute.hh

@@ -19,6 +19,7 @@
 
 struct Mesh;
 struct PointCloud;
+struct VolumeGrid;
 namespace blender::fn {
 namespace multi_function {
 class MultiFunction;

source/blender/blenkernel/BKE_volume_attribute.hh

@@ -17,23 +17,81 @@
 #  include <openvdb/openvdb.h>
 #endif
 
-#if 0
-struct VolumeGeometryGrid {
- public:
-  VolumeGeometryGrid();
-  ~VolumeGeometryGrid();
+namespace blender::bke {
 
-  VolumeGridType type() const;
+#ifdef WITH_OPENVDB
 
-  int64_t active_voxel_num() const;
+/**
+ * Result when looking up an attribute from some geometry with read and write access. After writing
+ * to the attribute, the #finish method has to be called. This may invalidate caches based on this
+ * attribute.
+ */
+template<typename T> struct AttributeGridWriter {
+  // using GridType =
 
-#  ifdef WITH_OPENVDB
-  openvdb::GridBase::Ptr grid_;
-#  endif
+  /**
+   * Grid pointer giving read and write access to the attribute. This may be empty.
+   */
+  GridT::Ptr VMutableArray<T> varray;
+  /**
+   * Domain where the attribute is stored on the geometry. Also determines the size of the virtual
+   * array.
+   */
+  eAttrDomain domain;
+  /**
+   * A function that has to be called after the attribute has been edited. This may be empty.
+   */
+  std::function<void()> tag_modified_fn;
+
+  operator bool() const
+  {
+    return this->varray;
+  }
+
+  /**
+   * Has to be called after the attribute has been modified.
+   */
+  void finish()
+  {
+    if (this->tag_modified_fn) {
+      this->tag_modified_fn();
+    }
+  }
 };
+
 #endif
 
-namespace blender::bke {
+/**
+ * A generic version of #AttributeWriter.
+ */
+struct GAttributeGridWriter {
+  VolumeGrid *grid;
+  eAttrDomain domain;
+  std::function<void()> tag_modified_fn;
+
+  operator bool() const
+  {
+    return this->grid;
+  }
+
+  void finish()
+  {
+    if (this->tag_modified_fn) {
+      this->tag_modified_fn();
+    }
+  }
+
+  template<typename T> AttributeWriter<T> typed() const
+  {
+    return {grid.typed<T>(), domain, tag_modified_fn};
+  }
+};
+
+/* OLD CODE
+ * OLD CODE
+ * OLD CODE
+ * OLD CODE
+ * OLD CODE */
 
 #ifdef WITH_OPENVDB
 

source/blender/blenlib/BLI_volume.hh

@@ -0,0 +1,67 @@
+/* SPDX-FileCopyrightText: 2023 Blender Foundation
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+/** \file
+ * \ingroup bli
+ */
+
+#ifdef WITH_OPENVDB
+#  include <openvdb/openvdb.h>
+#endif
+
+namespace blender {
+
+class CPPType;
+class ResourceScope;
+
+namespace volume_mask {
+
+/* Mask defined by active voxels of the grid. */
+class VolumeMask {
+#ifdef WITH_OPENVDB
+  const openvdb::MaskGrid &grid_;
+#endif
+
+ public:
+  bool is_empty() const;
+  int64_t min_voxel_count() const;
+
+#ifdef WITH_OPENVDB
+  const openvdb::MaskGrid &grid() const
+  {
+    return grid_;
+  }
+#endif
+};
+
+}  // namespace volume_mask
+
+using volume_mask::VolumeMask;
+
+struct VolumeGrid {
+#ifdef WITH_OPENVDB
+  openvdb::GridBase::Ptr grid_ = nullptr;
+#endif
+
+  /* Create an empty grid with a background value. */
+  static VolumeGrid create(ResourceScope &scope,
+                           const CPPType &type,
+                           const void *background_value);
+  /* Create an empty grid with the type default as background value. */
+  static VolumeGrid create(ResourceScope &scope, const CPPType &type);
+  /* Create a grid with the active volume mask voxels. */
+  static VolumeGrid create(ResourceScope &scope,
+                           const CPPType &type,
+                           const VolumeMask &mask,
+                           const void *inactive_value,
+                           const void *active_value);
+
+  int64_t voxel_count() const;
+  bool is_empty() const;
+  operator bool() const;
+};
+
+}  // namespace blender

source/blender/blenlib/CMakeLists.txt

@@ -380,6 +380,7 @@ set(SRC
   BLI_vector_set_slots.hh
   BLI_virtual_array.hh
   BLI_virtual_vector_array.hh
+  BLI_volume.hh
   BLI_voronoi_2d.h
   BLI_voxel.h
   BLI_winstuff.h
@@ -435,6 +436,20 @@ if(WITH_GMP)
   )
 endif()
 
+if(WITH_OPENVDB)
+  list(APPEND INC
+    ../../../intern/openvdb
+  )
+  list(APPEND INC_SYS
+    ${OPENVDB_INCLUDE_DIRS}
+  )
+  list(APPEND LIB
+    bf_intern_openvdb
+    ${OPENVDB_LIBRARIES}
+  )
+  add_definitions(-DWITH_OPENVDB ${OPENVDB_DEFINITIONS})
+endif()
+
 if(WIN32)
   if(WITH_BLENDER_THUMBNAILER)
     # Needed for querying the `thumbnailer .dll` in `winstuff.c`.

source/blender/functions/FN_volume_field.hh

@@ -14,60 +14,16 @@ namespace blender {
 class CPPType;
 class ResourceScope;
 template<typename T> class VArray;
+class VolumeGrid;
+class VolumeMask;
+
 namespace fn {
 class GFieldRef;
 }
 }  // namespace blender
 
-namespace blender::volume_mask {
-
-/* XXX Placeholder, this will define the grid voxels on which volume fields are evaluated. */
-class VolumeMask {
-#ifdef WITH_OPENVDB
-  const openvdb::MaskGrid &grid_;
-#endif
-
- public:
-  bool is_empty() const;
-  int64_t min_voxel_count() const;
-
-#ifdef WITH_OPENVDB
-  const openvdb::MaskGrid &grid() const
-  {
-    return grid_;
-  }
-#endif
-};
-
-}  // namespace blender::volume_mask
-
 namespace blender::fn {
 
-using volume_mask::VolumeMask;
-
-struct VolumeGrid {
-#ifdef WITH_OPENVDB
-  openvdb::GridBase::Ptr grid_ = nullptr;
-#endif
-
-  /* Create an empty grid with a background value. */
-  static VolumeGrid create(ResourceScope &scope,
-                           const CPPType &type,
-                           const void *background_value);
-  /* Create an empty grid with the type default as background value. */
-  static VolumeGrid create(ResourceScope &scope, const CPPType &type);
-  /* Create a grid with the active volume mask voxels. */
-  static VolumeGrid create(ResourceScope &scope,
-                           const CPPType &type,
-                           const VolumeMask &mask,
-                           const void *inactive_value,
-                           const void *active_value);
-
-  int64_t voxel_count() const;
-  bool is_empty() const;
-  operator bool() const;
-};
-
 void evaluate_procedure_on_varying_volume_fields(ResourceScope &scope,
                                                  const VolumeMask &mask,
                                                  const mf::Procedure &procedure,