Files
test2/source/blender/depsgraph/intern/builder/deg_builder_nodes.h
Sergey Sharybin c26566ad27 Drivers: Introduce the Context Properties
Drivers: Introduce the Context Properties

The goal: allow accessing context dependent data, such as active scene camera
without linking to a specific scene data-block. This is useful in cases when,
for example, geometry node setup needs to be aware of the camera position.

A possible work-around without changes like this is to have some scene
evaluation hook which will update driver variables for the currently evaluating
scene. But this raises an issue of linking: it is undesirable that the asset
scene is linked to the shot file.
Surely, it is possible to have post-evaluation handler to clear the variables,
but it all starts to be quite messy. Not to mention possible threading
conflicts.

Another possibility of introducing a way to achieve the goal is to make it so
the dependency graph somehow parses the python expression where artists can
(and already are trying to) type something like:

  depsgraph.scene.camera.matrix_world.col[3][0]

But this is not only tricky to implement properly and reliably, it hits two
limitations:

- Currently dependency graph can only easily resolve dependencies to a RNA
  property.

- Some properties access which are valid in Python are not considered valid
  RNA properties by the existing property resolution functions:

  `camera.matrix_world[3][0]` is a valid RNA property, but
  `camera.matrix_world.col[3][0]` is not.

Using driver variables allows to have visual feedback when the path resolution
fails, and there is no way to visualize errors in the python expression itself.

This change introduces the new variable type: Context Property. Using this
variable type makes allows to choose between Active Scene and Active View
Layer. These scene and view layer are resolved during the driver evaluation
time, based on the current dependency graph.

This allows to create a driver variable in the following configuration:

- Type: Context Property
- Context Property: Active Scene
- Path: camera.matrix_world[3][0]

The naming is a bit confusing. Tried my best to keep it clear keeping two
aspects in mind: using UI naming when possible, and follow the existing
naming.

A lot of the changes are related on making it so the required data is available
from the variable evaluation functions. It wasn't really clear what the data
would be, and the scope of the changes, so it is done together with the
functional changes.

It seems that there is some variable evaluation logic duplicated in the
`bpy_rna_driver.c`. This change does not change it. It is not really clear why
this separate code path with much more limited scope of supported target types
is even needed.

There is also a possible change in the behavior of the dependency graph: it
is now using ID of the resolved path when building driver variables. It used
to use the variable ID. In common cases they match, but when going into nested
data-blocks it is actually correct to use relation to the resolved ID. Not sure
if there was some code to ensure that, which now can be resolved. Also not sure
whether it is still needed to ensure the ID specified in the driver target is
build as well. Intuitively it is not needed.

Pull Request #105132
2023-03-06 16:01:47 +01:00

325 lines
13 KiB
C++

/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright 2013 Blender Foundation. All rights reserved. */
/** \file
* \ingroup depsgraph
*/
#pragma once
#include "intern/builder/deg_builder.h"
#include "intern/builder/deg_builder_key.h"
#include "intern/builder/deg_builder_map.h"
#include "intern/depsgraph_type.h"
#include "intern/node/deg_node_id.h"
#include "intern/node/deg_node_operation.h"
#include "DEG_depsgraph.h"
struct CacheFile;
struct Camera;
struct Collection;
struct FCurve;
struct FreestyleLineSet;
struct FreestyleLineStyle;
struct ID;
struct IDProperty;
struct Image;
struct Key;
struct LayerCollection;
struct Light;
struct LightProbe;
struct ListBase;
struct Main;
struct Mask;
struct Material;
struct MovieClip;
struct Object;
struct ParticleSettings;
struct Scene;
struct Simulation;
struct Speaker;
struct Tex;
struct VFont;
struct World;
struct bAction;
struct bArmature;
struct bConstraint;
struct bNodeSocket;
struct bNodeTree;
struct bPoseChannel;
struct bSound;
struct PointerRNA;
namespace blender::deg {
struct ComponentNode;
struct Depsgraph;
class DepsgraphBuilderCache;
struct IDNode;
struct OperationKey;
struct OperationNode;
struct TimeSourceNode;
class DepsgraphNodeBuilder : public DepsgraphBuilder {
public:
DepsgraphNodeBuilder(Main *bmain, Depsgraph *graph, DepsgraphBuilderCache *cache);
~DepsgraphNodeBuilder();
/* For given original ID get ID which is created by CoW system. */
ID *get_cow_id(const ID *id_orig) const;
/* Similar to above, but for the cases when there is no ID node we create
* one. */
ID *ensure_cow_id(ID *id_orig);
/* Helper wrapper function which wraps get_cow_id with a needed type cast. */
template<typename T> T *get_cow_datablock(const T *orig) const
{
return (T *)get_cow_id(&orig->id);
}
/* For a given COW datablock get corresponding original one. */
template<typename T> T *get_orig_datablock(const T *cow) const
{
return (T *)cow->id.orig_id;
}
virtual void begin_build();
virtual void end_build();
/**
* `id_cow_self` is the user of `id_pointer`,
* see also `LibraryIDLinkCallbackData` struct definition.
*/
int foreach_id_cow_detect_need_for_update_callback(ID *id_cow_self, ID *id_pointer);
IDNode *add_id_node(ID *id);
IDNode *find_id_node(const ID *id);
TimeSourceNode *add_time_source();
ComponentNode *add_component_node(ID *id, NodeType comp_type, const char *comp_name = "");
ComponentNode *find_component_node(const ID *id, NodeType comp_type, const char *comp_name = "");
OperationNode *add_operation_node(ComponentNode *comp_node,
OperationCode opcode,
const DepsEvalOperationCb &op = nullptr,
const char *name = "",
int name_tag = -1);
OperationNode *add_operation_node(ID *id,
NodeType comp_type,
const char *comp_name,
OperationCode opcode,
const DepsEvalOperationCb &op = nullptr,
const char *name = "",
int name_tag = -1);
OperationNode *add_operation_node(ID *id,
NodeType comp_type,
OperationCode opcode,
const DepsEvalOperationCb &op = nullptr,
const char *name = "",
int name_tag = -1);
OperationNode *ensure_operation_node(ID *id,
NodeType comp_type,
const char *comp_name,
OperationCode opcode,
const DepsEvalOperationCb &op = nullptr,
const char *name = "",
int name_tag = -1);
OperationNode *ensure_operation_node(ID *id,
NodeType comp_type,
OperationCode opcode,
const DepsEvalOperationCb &op = nullptr,
const char *name = "",
int name_tag = -1);
bool has_operation_node(ID *id,
NodeType comp_type,
const char *comp_name,
OperationCode opcode,
const char *name = "",
int name_tag = -1);
OperationNode *find_operation_node(const ID *id,
NodeType comp_type,
const char *comp_name,
OperationCode opcode,
const char *name = "",
int name_tag = -1);
OperationNode *find_operation_node(const ID *id,
NodeType comp_type,
OperationCode opcode,
const char *name = "",
int name_tag = -1);
OperationNode *find_operation_node(const OperationKey &key);
virtual void build_id(ID *id);
/* Build function for ID types that do not need their own build_xxx() function. */
virtual void build_generic_id(ID *id);
virtual void build_idproperties(IDProperty *id_property);
virtual void build_scene_render(Scene *scene, ViewLayer *view_layer);
virtual void build_scene_parameters(Scene *scene);
virtual void build_scene_compositor(Scene *scene);
virtual void build_layer_collections(ListBase *lb);
virtual void build_view_layer(Scene *scene,
ViewLayer *view_layer,
eDepsNode_LinkedState_Type linked_state);
virtual void build_collection(LayerCollection *from_layer_collection, Collection *collection);
virtual void build_object(int base_index,
Object *object,
eDepsNode_LinkedState_Type linked_state,
bool is_visible);
virtual void build_object_instance_collection(Object *object, bool is_object_visible);
virtual void build_object_from_layer(int base_index,
Object *object,
eDepsNode_LinkedState_Type linked_state);
virtual void build_object_flags(int base_index,
Object *object,
eDepsNode_LinkedState_Type linked_state);
virtual void build_object_modifiers(Object *object);
virtual void build_object_data(Object *object);
virtual void build_object_data_camera(Object *object);
virtual void build_object_data_geometry(Object *object);
virtual void build_object_data_geometry_datablock(ID *obdata);
virtual void build_object_data_light(Object *object);
virtual void build_object_data_lightprobe(Object *object);
virtual void build_object_data_speaker(Object *object);
virtual void build_object_transform(Object *object);
virtual void build_object_constraints(Object *object);
virtual void build_object_pointcache(Object *object);
virtual void build_pose_constraints(Object *object, bPoseChannel *pchan, int pchan_index);
virtual void build_rigidbody(Scene *scene);
virtual void build_particle_systems(Object *object, bool is_object_visible);
virtual void build_particle_settings(ParticleSettings *part);
/**
* Build graph nodes for #AnimData block and any animated images used.
* \param id: ID-Block which hosts the #AnimData
*/
virtual void build_animdata(ID *id);
virtual void build_animdata_nlastrip_targets(ListBase *strips);
/**
* Build graph nodes to update the current frame in image users.
*/
virtual void build_animation_images(ID *id);
virtual void build_action(bAction *action);
/**
* Build graph node(s) for Driver
* \param id: ID-Block that driver is attached to
* \param fcurve: Driver-FCurve
* \param driver_index: Index in animation data drivers list
*/
virtual void build_driver(ID *id, FCurve *fcurve, int driver_index);
virtual void build_driver_variables(ID *id, FCurve *fcurve);
/* Build operations of a property value from which is read by a driver target.
*
* The driver target points to a data-block (or a sub-data-block like View Layer).
* This data-block is presented in the interface as a "Prop" and its resolved RNA pointer is
* passed here as `target_prop`.
*
* The tricky part (and a bit confusing naming) is that the driver target accesses a property of
* the `target_prop` to get its value. The property which is read to give an actual target value
* is denoted by its RNA path relative to the `target_prop`. In the interface it is called "Path"
* and here it is called `rna_path_from_target_prop`. */
virtual void build_driver_id_property(const PointerRNA &target_prop,
const char *rna_path_from_target_prop);
virtual void build_parameters(ID *id);
virtual void build_dimensions(Object *object);
virtual void build_ik_pose(Object *object, bPoseChannel *pchan, bConstraint *con);
virtual void build_splineik_pose(Object *object, bPoseChannel *pchan, bConstraint *con);
virtual void build_rig(Object *object);
virtual void build_armature(bArmature *armature);
virtual void build_armature_bones(ListBase *bones);
virtual void build_shapekeys(Key *key);
virtual void build_camera(Camera *camera);
virtual void build_light(Light *lamp);
virtual void build_nodetree(bNodeTree *ntree);
virtual void build_nodetree_socket(bNodeSocket *socket);
virtual void build_material(Material *ma);
virtual void build_materials(Material **materials, int num_materials);
virtual void build_freestyle_lineset(FreestyleLineSet *fls);
virtual void build_freestyle_linestyle(FreestyleLineStyle *linestyle);
virtual void build_texture(Tex *tex);
virtual void build_image(Image *image);
virtual void build_world(World *world);
virtual void build_cachefile(CacheFile *cache_file);
virtual void build_mask(Mask *mask);
virtual void build_movieclip(MovieClip *clip);
virtual void build_lightprobe(LightProbe *probe);
virtual void build_speaker(Speaker *speaker);
virtual void build_sound(bSound *sound);
virtual void build_simulation(Simulation *simulation);
virtual void build_scene_sequencer(Scene *scene);
virtual void build_scene_audio(Scene *scene);
virtual void build_scene_speakers(Scene *scene, ViewLayer *view_layer);
virtual void build_vfont(VFont *vfont);
/* Per-ID information about what was already in the dependency graph.
* Allows to re-use certain values, to speed up following evaluation. */
struct IDInfo {
/* Copy-on-written pointer of the corresponding ID. */
ID *id_cow;
/* Mask of visible components from previous state of the
* dependency graph. */
IDComponentsMask previously_visible_components_mask;
/* Special evaluation flag mask from the previous depsgraph. */
uint32_t previous_eval_flags;
/* Mesh CustomData mask from the previous depsgraph. */
DEGCustomDataMeshMasks previous_customdata_masks;
};
protected:
/* Entry tags from the previous state of the dependency graph.
* Stored before the graph is re-created so that they can be transferred over. */
Vector<PersistentOperationKey> saved_entry_tags_;
struct BuilderWalkUserData {
DepsgraphNodeBuilder *builder;
};
static void modifier_walk(void *user_data,
struct Object *object,
struct ID **idpoin,
int cb_flag);
static void constraint_walk(bConstraint *constraint,
ID **idpoin,
bool is_reference,
void *user_data);
void tag_previously_tagged_nodes();
/**
* Check for IDs that need to be flushed (COW-updated)
* because the depsgraph itself created or removed some of their evaluated dependencies.
*/
void update_invalid_cow_pointers();
/* State which demotes currently built entities. */
Scene *scene_;
ViewLayer *view_layer_;
int view_layer_index_;
/* NOTE: Collection are possibly built recursively, so be careful when
* setting the current state. */
Collection *collection_;
/* Accumulated flag over the hierarchy of currently building collections.
* Denotes whether all the hierarchy from parent of `collection_` to the
* very root is visible (aka not restricted.). */
bool is_parent_collection_visible_;
/* Indexed by original ID.session_uuid, values are IDInfo. */
Map<uint, IDInfo *> id_info_hash_;
/* Set of IDs which were already build. Makes it easier to keep track of
* what was already built and what was not. */
BuilderMap built_map_;
};
} // namespace blender::deg