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Diffstat (limited to 'source/blender/depsgraph/intern/builder/deg_builder_relations_drivers.cc')
| -rw-r--r-- | source/blender/depsgraph/intern/builder/deg_builder_relations_drivers.cc | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/source/blender/depsgraph/intern/builder/deg_builder_relations_drivers.cc b/source/blender/depsgraph/intern/builder/deg_builder_relations_drivers.cc new file mode 100644 index 00000000000..717c8300f9b --- /dev/null +++ b/source/blender/depsgraph/intern/builder/deg_builder_relations_drivers.cc @@ -0,0 +1,258 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) 2013 Blender Foundation. + * All rights reserved. + */ + +/** \file + * \ingroup depsgraph + * + * Methods for constructing depsgraph relations for drivers. + */ + +#include "intern/builder/deg_builder_relations_drivers.h" + +#include <cstring> + +#include "DNA_anim_types.h" + +#include "BKE_anim_data.h" + +#include "intern/builder/deg_builder_relations.h" +#include "intern/depsgraph_relation.h" +#include "intern/node/deg_node.h" + +namespace blender { +namespace deg { + +DriverDescriptor::DriverDescriptor(PointerRNA *id_ptr, FCurve *fcu) + : rna_prefix(), + rna_suffix(), + id_ptr_(id_ptr), + fcu_(fcu), + driver_relations_needed_(false), + pointer_rna_(), + property_rna_(nullptr), + is_array_(false) +{ + driver_relations_needed_ = determine_relations_needed(); + split_rna_path(); +} + +bool DriverDescriptor::determine_relations_needed() +{ + if (fcu_->array_index > 0) { + /* Drivers on array elements always need relations. */ + is_array_ = true; + return true; + } + + if (!resolve_rna()) { + /* Properties that don't exist can't cause threading issues either. */ + return false; + } + + if (RNA_property_array_check(property_rna_)) { + /* Drivers on array elements always need relations. */ + is_array_ = true; + return true; + } + + /* Drivers on Booleans and Enums (when used as bitflags) can write to the same memory location, + * so they need relations between each other. */ + return ELEM(RNA_property_type(property_rna_), PROP_BOOLEAN, PROP_ENUM); +} + +bool DriverDescriptor::driver_relations_needed() const +{ + return driver_relations_needed_; +} + +bool DriverDescriptor::is_array() const +{ + return is_array_; +} + +/* Assumes that 'other' comes from the same RNA group, that is, has the same RNA path prefix. */ +bool DriverDescriptor::is_same_array_as(const DriverDescriptor &other) const +{ + if (!is_array_ || !other.is_array_) { + return false; + } + return rna_suffix == other.rna_suffix; +} + +OperationKey DriverDescriptor::depsgraph_key() const +{ + return OperationKey(id_ptr_->owner_id, + NodeType::PARAMETERS, + OperationCode::DRIVER, + fcu_->rna_path, + fcu_->array_index); +} + +void DriverDescriptor::split_rna_path() +{ + const char *last_dot = strrchr(fcu_->rna_path, '.'); + if (last_dot == nullptr || last_dot[1] == '\0') { + rna_prefix = StringRef(); + rna_suffix = StringRef(fcu_->rna_path); + return; + } + + rna_prefix = StringRef(fcu_->rna_path, last_dot); + rna_suffix = StringRef(last_dot + 1); +} + +bool DriverDescriptor::resolve_rna() +{ + return RNA_path_resolve_property(id_ptr_, fcu_->rna_path, &pointer_rna_, &property_rna_); +} + +static bool is_reachable(const Node *const from, const Node *const to) +{ + if (from == to) { + return true; + } + + // Perform a graph walk from 'to' towards its incoming connections. + // Walking from 'from' towards its outgoing connections is 10x slower on the Spring rig. + deque<const Node *> queue; + Set<const Node *> seen; + queue.push_back(to); + while (!queue.empty()) { + // Visit the next node to inspect. + const Node *visit = queue.back(); + queue.pop_back(); + + if (visit == from) { + return true; + } + + // Queue all incoming relations that we haven't seen before. + for (Relation *relation : visit->inlinks) { + const Node *prev_node = relation->from; + if (seen.add(prev_node)) { + queue.push_back(prev_node); + } + } + } + return false; +} + +/* **** DepsgraphRelationBuilder functions **** */ + +void DepsgraphRelationBuilder::build_driver_relations() +{ + for (IDNode *id_node : graph_->id_nodes) { + build_driver_relations(id_node); + } +} + +void DepsgraphRelationBuilder::build_driver_relations(IDNode *id_node) +{ + /* Add relations between drivers that write to the same datablock. + * + * This prevents threading issues when two separate RNA properties write to + * the same memory address. For example: + * - Drivers on individual array elements, as the animation system will write + * the whole array back to RNA even when changing individual array value. + * - Drivers on RNA properties that map to a single bit flag. Changing the RNA + * value will write the entire int containing the bit, in a non-thread-safe + * way. + */ + ID *id_orig = id_node->id_orig; + AnimData *adt = BKE_animdata_from_id(id_orig); + if (adt == nullptr) { + return; + } + + // Mapping from RNA prefix -> set of driver descriptors: + Map<string, Vector<DriverDescriptor>> driver_groups; + + PointerRNA id_ptr; + RNA_id_pointer_create(id_orig, &id_ptr); + + LISTBASE_FOREACH (FCurve *, fcu, &adt->drivers) { + if (fcu->rna_path == nullptr) { + continue; + } + + DriverDescriptor driver_desc(&id_ptr, fcu); + if (!driver_desc.driver_relations_needed()) { + continue; + } + + driver_groups.lookup_or_add_default_as(driver_desc.rna_prefix).append(driver_desc); + } + + for (Span<DriverDescriptor> prefix_group : driver_groups.values()) { + // For each node in the driver group, try to connect it to another node + // in the same group without creating any cycles. + int num_drivers = prefix_group.size(); + if (num_drivers < 2) { + // A relation requires two drivers. + continue; + } + for (int from_index = 0; from_index < num_drivers; ++from_index) { + const DriverDescriptor &driver_from = prefix_group[from_index]; + Node *op_from = get_node(driver_from.depsgraph_key()); + + // Start by trying the next node in the group. + for (int to_offset = 1; to_offset < num_drivers; ++to_offset) { + const int to_index = (from_index + to_offset) % num_drivers; + const DriverDescriptor &driver_to = prefix_group[to_index]; + Node *op_to = get_node(driver_to.depsgraph_key()); + + // Duplicate drivers can exist (see T78615), but cannot be distinguished by OperationKey + // and thus have the same depsgraph node. Relations between those drivers should not be + // created. This not something that is expected to happen (both the UI and the Python API + // prevent duplicate drivers), it did happen in a file and it is easy to deal with here. + if (op_from == op_to) { + continue; + } + + if (from_index < to_index && driver_from.is_same_array_as(driver_to)) { + // This is for adding a relation like `color[0]` -> `color[1]`. + // When the search for another driver wraps around, we cannot blindly add relations any + // more. + } + else { + // Investigate whether this relation would create a dependency cycle. + // Example graph: + // A -> B -> C + // and investigating a potential connection C->A. Because A->C is an + // existing transitive connection, adding C->A would create a cycle. + if (is_reachable(op_to, op_from)) { + continue; + } + + // No need to directly connect this node if there is already a transitive connection. + if (is_reachable(op_from, op_to)) { + break; + } + } + + add_operation_relation( + op_from->get_exit_operation(), op_to->get_entry_operation(), "Driver Serialization"); + break; + } + } + } +} + +} // namespace deg +} // namespace blender |