Depsgraph: Modernization #121019

New Issue

Sergey Sharybin · 2024-04-24T12:35:58+02:00

Sergey Sharybin commented

2024-04-24 12:35:58 +02:00

This task is aimed to be a parent task for the dependency graph upgrades for an upgraded requirements. The goal is to convert the current system to a better state, without involving another big rewrite, as it is not very practical.

In this task it is more a compilation of aspects which needs to be addressed, with a brief description. Those could be split into separate "sub-tasks" in order to allow more detailed design and discussions.

API

Use deg::Depsgraph everywhere, avoiding the reinterpert cast from/to opaque pointer. The deg::Depsgraph definition could still stay private to the despgraph module.
Support tagging specific RNA properties, by their PointerRNA. Goal: allow tagging individual custom properties, and limit updates to things which are connected to it.
Allow sub-classing AbstractBuilderPipeline outside of the DEG module.
More "batched" iteration of instances, providing array of transforms more directly, avoiding creation of temporary in-memory objects.

Builder

Merge Nodes and Relations builder
Cleanup of the collections builder, with more clear separation between collections referenced by objects, and collections coming from the layer collections.
Move ID builders to ID_Type.
Solve implicit decisions in the RNANodeQuery::construct_node_identifier. Possibly make it so RNA gives require information in a generic manner (which will be needed to support tagging RNA properties).
Revisit the visiiblity optimization. It works, but with limitations, and implementation feels a bit ad-hocky. Feels like it could become more prominent core feature, with clarity of what each visibility means at every step of the depsgraph timelife.

Debugging

Technical artists should access to performance and relation debugging as a core functionality. Currently it is done via gnuplot for timing and graphviz for relations. The graphviz is especially bad, as it only handles very small graphs.

Make performance debugging a core feature in Blender, displayed in the Space Info
Similarly, make make it possible to debug and visualize dependencies (OppsWindow)

Optimizations

Avoid unnecessary re-evaluations when a single custom property is changed (see the RNA property tagging).
Allow weak pointers to IDs in custom properties, avoiding all the IDs referenced by custom properties becoming a part of the depsgraph.
Revisit the situation about unwanted evaluations (like, via disabled modifiers/constraints). A lot of work was done, but is unclear if all use-cases were covered. Need to go over reports, like #99572, #89599, #73199, #111021.
Tighter integration with geometry nodes, especially the Switch node. Goal: avoid evaluation of geometry which is referenced by the geometry node tree, but is not needed for its actual evaluation.

This task is aimed to be a parent task for the dependency graph upgrades for an upgraded requirements. The goal is to convert the current system to a better state, without involving another big rewrite, as it is not very practical. In this task it is more a compilation of aspects which needs to be addressed, with a brief description. Those could be split into separate "sub-tasks" in order to allow more detailed design and discussions. **API** * Use `deg::Depsgraph` everywhere, avoiding the reinterpert cast from/to opaque pointer. The `deg::Depsgraph` definition could still stay private to the despgraph module. * Support tagging specific RNA properties, by their `PointerRNA`. Goal: allow tagging individual custom properties, and limit updates to things which are connected to it. * Allow sub-classing `AbstractBuilderPipeline` outside of the DEG module. * More "batched" iteration of instances, providing array of transforms more directly, avoiding creation of temporary in-memory objects. **Builder** * Merge Nodes and Relations builder * Cleanup of the collections builder, with more clear separation between collections referenced by objects, and collections coming from the layer collections. * Move ID builders to `ID_Type`. * Solve implicit decisions in the `RNANodeQuery::construct_node_identifier`. Possibly make it so RNA gives require information in a generic manner (which will be needed to support tagging RNA properties). * Revisit the visiiblity optimization. It works, but with limitations, and implementation feels a bit ad-hocky. Feels like it could become more prominent core feature, with clarity of what each visibility means at every step of the depsgraph timelife. **Debugging** Technical artists should access to performance and relation debugging as a core functionality. Currently it is done via gnuplot for timing and graphviz for relations. The graphviz is especially bad, as it only handles very small graphs. * Make performance debugging a core feature in Blender, displayed in the Space Info * Similarly, make make it possible to debug and visualize dependencies ([OppsWindow](https://docs.blender.org/api/htmlII/x3447.html)) **Optimizations** * Avoid unnecessary re-evaluations when a single custom property is changed (see the RNA property tagging). * Allow weak pointers to IDs in custom properties, avoiding all the IDs referenced by custom properties becoming a part of the depsgraph. * Revisit the situation about unwanted evaluations (like, via disabled modifiers/constraints). A lot of work was done, but is unclear if all use-cases were covered. Need to go over reports, like #99572, #89599, #73199, #111021. * Tighter integration with geometry nodes, especially the Switch node. Goal: avoid evaluation of geometry which is referenced by the geometry node tree, but is not needed for its actual evaluation.

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Depsgraph: Modernization #121019