bevy/crates/bevy_transform
James Liu eaeba0866d Parallelized transform propagation (#4775)
# Objective
Fixes #4697. Hierarchical propagation of properties, currently only Transform -> GlobalTransform, can be a very expensive operation. Transform propagation is a strict dependency for anything positioned in world-space. In large worlds, this can take quite a bit of time, so limiting it to a single thread can result in poor CPU utilization as it bottlenecks the rest of the frame's systems.

## Solution

 - Move transforms without a parent or a child (free-floating (Global)Transform) entities into a separate parallel system.
 - Chunk the hierarchy based on the root entities and process it in parallel with `Query::par_for_each_mut`. 
 - Utilize the hierarchy's specific properties introduced in #4717 to allow for safe use of `Query::get_unchecked` on multiple threads. Assuming each child is unique in the hierarchy, it is impossible to have an aliased `&mut GlobalTransform` so long as we verify that the parent for a child is the same one propagated from.

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## Changelog
Removed: `transform_propagate_system` is no longer `pub`.
2022-11-21 18:18:38 +00:00
..
src Parallelized transform propagation (#4775) 2022-11-21 18:18:38 +00:00
Cargo.toml Parallelized transform propagation (#4775) 2022-11-21 18:18:38 +00:00
README.md transform: remove some dependencies and cleanup 2020-07-10 01:49:23 -07:00

Bevy Transform

This crate is largely a 1:1 port from legion_transform (ecs: legion, math: nalgebra) to bevy (ecs: bevy_ecs, math: glam)