67c7485bfd
This refactors the lifetime analysis of anonymous attributes in geometry nodes. The refactor has a couple of goals: * Use a better and simpler abstraction that can be used when building the lazy-function graph. We currently have a bunch of duplicate code to handle "field source" and "caller propagation" attributes. This is now unified so that one only has to worry about one kind of "reference sets". * Make the abstraction compatible with handling bundles and closures in case we want to support them in the future. Both types can contain geometries and fields so they need to be taken into account when determining lifetimes. * Make more parts independent of the concept of "anonymous attributes". In theory, there could be more kinds of referenced data whose lifetimes need to be managed. I don't have any concrete plans for adding any though. At its core, deterministic anonymous attributes still work the same they have been since they became deterministic [0]. Even the generated lazy-function graph is still pretty much or even exactly the same as before. The patch renames `AnonymousAttributeSet` to the more general `GeometryNodesReferenceSet` which is more. This also makes more places independent of the concept of anonymous attributes. Functionally, this still the same though. It's only used in the internals of geometry nodes nowadays. Most code just gets an `AttributeFilter` that is based on it. [0]: https://archive.blender.org/developer/D16858 Pull Request: https://projects.blender.org/blender/blender/pulls/128667
102 lines
3.4 KiB
C++
102 lines
3.4 KiB
C++
/* SPDX-FileCopyrightText: 2024 Blender Authors
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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#pragma once
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/**
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* Geometry nodes has the concept of anonymous attributes. These are attributes that are created by
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* some node with an internal name that is not exposed to the user. The only way to use this
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* attribute is to make a link in the node tree to the node that should use it. This explicitness
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* allows us to automatically determine when anonymous attributes are not needed anymore and should
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* be deleted (or not created in the first place).
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*
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* This file is used to determine the lifetimes of these anonymous attributes. The logic is fairly
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* straight forward to extend to other kinds of referenced data, but for now we only have anonymous
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* attributes.
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*
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* The lifetime analysis uses information provided in the node declaration and hardcoded behavior
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* for some special nodes like zones to determine the following things among others.
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* - Where are new references (like anonymous attributes) created?
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* - Which data sockets (like geometry) contain the referenced data?
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* - Which nodes have to propagate which referenced data to which outputs?
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*
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* This information is later used when evaluating geometry nodes to reduce the lifetime of
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* anonymous attributes automatically.
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*/
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#include "BLI_bit_group_vector.hh"
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#include "BLI_vector.hh"
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#include "DNA_node_types.h"
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#include "NOD_node_declaration.hh"
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namespace blender::bke::node_tree_reference_lifetimes {
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enum class ReferenceSetType {
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/**
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* Corresponds to geometry outputs that may contain attributes that are propagated from a group
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* input. In such cases, the caller may provide a set of attributes that should be propagated.
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*/
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GroupOutputData,
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/**
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* Field inputs may require attributes that need to be propagated from other geometry inputs to
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* the node that evaluates the field.
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*/
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GroupInputReferenceSet,
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/**
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* Locally created anonymous attributes (like with the Capture Attribute node) need to be
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* propagated to the nodes that use them or even to the group output.
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*/
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LocalReferenceSet,
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};
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struct ReferenceSetInfo {
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ReferenceSetType type;
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union {
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/** Used for group interface sockets. */
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int index;
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/** Used for local sockets. */
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const bNodeSocket *socket;
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};
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/**
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* Sockets that may contain the referenced data (e.g. the geometry output of a Capture Attribute
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* node).
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*/
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Vector<const bNodeSocket *> potential_data_origins;
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ReferenceSetInfo(ReferenceSetType type, const int index) : type(type), index(index)
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{
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BLI_assert(
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ELEM(type, ReferenceSetType::GroupInputReferenceSet, ReferenceSetType::GroupOutputData));
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}
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ReferenceSetInfo(ReferenceSetType type, const bNodeSocket *socket) : type(type), socket(socket)
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{
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BLI_assert(ELEM(type, ReferenceSetType::LocalReferenceSet));
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}
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friend std::ostream &operator<<(std::ostream &stream, const ReferenceSetInfo &source);
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};
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struct ReferenceLifetimesInfo {
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Vector<ReferenceSetInfo> reference_sets;
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/**
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* Has a bit for each socket and each reference set. If the bit is set, the corresponding
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* reference set should be propagated to that socket.
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*/
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BitGroupVector<> required_data_by_socket;
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/**
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* Relations used for group nodes that use this group.
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*/
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nodes::aal::RelationsInNode tree_relations;
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};
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bool analyse_reference_lifetimes(bNodeTree &tree);
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} // namespace blender::bke::node_tree_reference_lifetimes
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