scene/volume.h

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/* SPDX-FileCopyrightText: 2020-2022 Blender Foundation
 *
 * SPDX-License-Identifier: Apache-2.0 */
 
#pragma once
 
#include "graph/node.h"
 
#include "scene/mesh.h"
 
#ifdef WITH_OPENVDB
#  include <openvdb/openvdb.h>
#endif
 
CCL_NAMESPACE_BEGIN
 
class Object;
class Octree;
 
enum VolumeRenderingAlgorithm {
  NULL_SCATTERING,
  RAY_MARCHING,
  NONE,
};
 
class Volume : public Mesh {
 public:
  NODE_DECLARE
 
  Volume();
 
  NODE_SOCKET_API(float, step_size)
  NODE_SOCKET_API(bool, object_space)
  NODE_SOCKET_API(float, velocity_scale)
 
  /* Merge attributes for efficiency, call right after creating them. */
  void merge_grids(const Scene *scene);
 
  void clear(bool preserve_shaders = false) override;
};
 
class VolumeManager {
 public:
  VolumeManager();
  ~VolumeManager();
 
  void device_update(Device *, DeviceScene *, const Scene *, Progress &);
  void device_free(DeviceScene *);
 
  /* Tag volume octree for update when scene changes. */
  void tag_update();
  void tag_update(const Shader *shader);
  void tag_update(const Object *object, const uint32_t flag);
  void tag_update(const Geometry *geometry);
  void tag_update_indices();
 
  /* Check whether the shader is a homogeneous volume. */
  static bool is_homogeneous_volume(const Object *, const Shader *);
 
 private:
  /* Initialize octrees from the volumes in the scene. */
  void initialize_octree(const Scene *, Progress &);
 
  /* Build octrees based on the volume density. */
  void build_octree(Device *, Progress &);
 
  /* Update the object and shader index of octree root nodes. */
  void update_root_indices(DeviceScene *, const Scene *) const;
 
  /* Converting the octrees into an array for uploading to the kernel. */
  void flatten_octree(DeviceScene *, const Scene *) const;
 
  /* Count all the nodes of the octrees. */
  void update_num_octree_nodes();
  int num_octree_nodes() const;
  int num_octree_roots() const;
 
  /* When running Blender with `--log-level debug`, an octree visualization is written to
   * `filename`, which is a Python script that can be run inside Blender. */
  std::string visualize_octree(const char *filename) const;
 
  /* Step size for ray marching. */
  void update_step_size(const Scene *, DeviceScene *) const;
 
  /* One octree per object per shader. */
  std::map<std::pair<const Object *, const Shader *>, std::shared_ptr<Octree>> object_octrees_;
 
  bool update_root_indices_ = false;
  bool need_rebuild_;
  bool update_visualization_ = false;
  int num_octree_nodes_;
  int num_octree_roots_;
 
  VolumeRenderingAlgorithm last_algorithm = NONE;
 
#ifdef WITH_OPENVDB
  /* Create SDF grid for mesh volumes, to determine whether a certain point is in the
   * interior of the mesh. This reduces evaluation time needed for heterogeneous volume. */
  openvdb::BoolGrid::ConstPtr mesh_to_sdf_grid(const Mesh *mesh,
                                               const Shader *shader,
                                               const float half_width);
  openvdb::BoolGrid::ConstPtr get_vdb(const Geometry *, const Shader *) const;
  std::map<std::pair<const Geometry *, const Shader *>, openvdb::BoolGrid::ConstPtr> vdb_map_;
#endif
};
 
CCL_NAMESPACE_END