Implement the `AnimationGraph`, allowing for multiple animations to be blended together. #11989

pcwalton · 2024-02-20T01:58:03Z

This is an implementation of RFC #51: https://github.com/bevyengine/rfcs/blob/main/rfcs/51-animation-composition.md

Note that the implementation strategy is different from the one outlined in that RFC, because two-phase animation has now landed.

Objective

Bevy needs animation blending. The RFC for this is RFC 51.

Solution

This is an implementation of the RFC. Note that the implementation strategy is different from the one outlined there, because two-phase animation has now landed.

This is just a draft to get the conversation started. Currently we're missing a few things:

A fully-fleshed-out mechanism for transitions
A serialization format for AnimationGraphs
Examples are broken, other than animated_fox
Documentation

Changelog

Added

The AnimationPlayer has been reworked to support blending multiple animations together through an AnimationGraph, and as such will no longer function unless a Handle<AnimationGraph> has been added to the entity containing the player. See RFC 51 for more details.
Transition functionality has moved from the AnimationPlayer to a new component, AnimationTransitions, which works in tandem with the AnimationGraph.

Migration Guide

AnimationPlayers can no longer play animations by themselves and need to be paired with a Handle<AnimationGraph>. Code that was using AnimationPlayer to play animations will need to create an AnimationGraph asset first, add a node for the clip (or clips) you want to play, and then supply the index of that node to the AnimationPlayer's play method.
The AnimationPlayer::play_with_transition() method has been removed and replaced with the AnimationTransitions component. If you were previously using AnimationPlayer::play_with_transition(), add all animations that you were playing to the AnimationGraph, and create an AnimationTransitions component to manage the blending between them.

blended together. This is an implementation of RFC bevyengine#51: https://github.com/bevyengine/rfcs/blob/main/rfcs/51-animation-composition.md Note that the implementation strategy is different from the one outlined in that RFC, because two-phase animation has now landed.

pcwalton · 2024-02-20T20:03:44Z

I removed the Controversial label as this is implementing an approved RFC.

djeedai

Looks good overall, no special concern or comment

crates/bevy_animation/src/graph.rs

This isn't done yet.

github-actions · 2024-02-28T05:50:42Z

The generated examples/README.md is out of sync with the example metadata in Cargo.toml or the example readme template. Please run cargo run -p build-templated-pages -- update examples to update it, and commit the file change.

github-actions · 2024-02-28T05:58:11Z

The generated examples/README.md is out of sync with the example metadata in Cargo.toml or the example readme template. Please run cargo run -p build-templated-pages -- update examples to update it, and commit the file change.

github-actions · 2024-02-28T09:50:02Z

The generated examples/README.md is out of sync with the example metadata in Cargo.toml or the example readme template. Please run cargo run -p build-templated-pages -- update examples to update it, and commit the file change.

pcwalton · 2024-03-05T05:30:21Z

OK, I'm much happier with this. I've solved the problems of animation ordering and removed the "scheduled animation" overhead. This should be ready for re-review.

pcwalton · 2024-03-06T00:09:01Z

Improved the example a bit, thanks to @rparrett.

james7132

I'm overall happy with the current state of this PR. Given the size of the PR, I'm opting to skip the smaller nits and opt to iteratively improve upon the implementation.

crates/bevy_animation/src/lib.rs

crates/bevy_animation/src/graph.rs

alice-i-cecile

Really pleased with the documentation and general care shown here. I'm content with the level of review from subject matter experts, and the examples appear to work correctly for me.

There's definitely some general-purpose abstractions missing on the asset management side, but I'm content with this for now. It'll be useful to have this in place to help us figure out a design there.

However, I'm getting a bunch of warnings like:

2024-03-07T15:32:36.708431Z WARN bevy_animation: Couldn't find the animation player 53v1 for the target entity 49v1 (Some("b_LeftLeg02_016"))

on both the animated_fox and animation_graph examples. This doesn't appear to be present on main. I suspect a system ordering problem.

Once those are fixed up I'm happy to approve and merge.

rparrett · 2024-03-07T15:47:30Z

2024-03-07T15:32:36.708431Z WARN bevy_animation: Couldn't find the animation player 53v1 for the target entity 49v1 (Some("b_LeftLeg02_016"))

These started showing up after 283a4d0.

I have some more ideas for the examples, but I will follow up later. They're definitely in a good enough state.

So "approved," but I only looked at the examples.

and is harmless, and fix the system order in the examples

pcwalton · 2024-03-07T18:05:50Z

I demoted the warnings to traces because they're relatively common and harmless now. They'll occur whenever you load a glTF and haven't added an AnimationGraph. glTF has no concept of animation blending, so Bevy has no way to figure out what you want, and you have to add it manually. Until you do, animations won't play. This is documented in the migration guide. (It might be convenient to have some sort of default AnimationGraph, but that can be a followup.)

I also switched the system order to hopefully avoid 1-frame lag (and avoid those traces) in the examples.

…e blended together. (bevyengine#11989) This is an implementation of RFC bevyengine#51: https://github.com/bevyengine/rfcs/blob/main/rfcs/51-animation-composition.md Note that the implementation strategy is different from the one outlined in that RFC, because two-phase animation has now landed. # Objective Bevy needs animation blending. The RFC for this is [RFC 51]. ## Solution This is an implementation of the RFC. Note that the implementation strategy is different from the one outlined there, because two-phase animation has now landed. This is just a draft to get the conversation started. Currently we're missing a few things: - [x] A fully-fleshed-out mechanism for transitions - [x] A serialization format for `AnimationGraph`s - [x] Examples are broken, other than `animated_fox` - [x] Documentation --- ## Changelog ### Added * The `AnimationPlayer` has been reworked to support blending multiple animations together through an `AnimationGraph`, and as such will no longer function unless a `Handle<AnimationGraph>` has been added to the entity containing the player. See [RFC 51] for more details. * Transition functionality has moved from the `AnimationPlayer` to a new component, `AnimationTransitions`, which works in tandem with the `AnimationGraph`. ## Migration Guide * `AnimationPlayer`s can no longer play animations by themselves and need to be paired with a `Handle<AnimationGraph>`. Code that was using `AnimationPlayer` to play animations will need to create an `AnimationGraph` asset first, add a node for the clip (or clips) you want to play, and then supply the index of that node to the `AnimationPlayer`'s `play` method. * The `AnimationPlayer::play_with_transition()` method has been removed and replaced with the `AnimationTransitions` component. If you were previously using `AnimationPlayer::play_with_transition()`, add all animations that you were playing to the `AnimationGraph`, and create an `AnimationTransitions` component to manage the blending between them. [RFC 51]: https://github.com/bevyengine/rfcs/blob/main/rfcs/51-animation-composition.md --------- Co-authored-by: Rob Parrett <robparrett@gmail.com>

…14853) # Objective Add a convenience constructor to make simple animation graphs easier to build. I've had some notes about attempting this since #11989 that I just remembered after seeing #14852. This partially addresses #14852, but I don't really know animation well enough to write all of the documentation it's asking for. ## Solution Add `AnimationGraph::from_clips` and use it to simplify `animated_fox`. Do some other little bits of incidental cleanup and documentation . ## Testing I ran `cargo run --example animated_fox`.

james7132 self-requested a review February 20, 2024 06:14

alice-i-cecile added C-Feature A new feature, making something new possible A-Editor Graphical tools to make Bevy games X-Controversial There is active debate or serious implications around merging this PR labels Feb 20, 2024

pcwalton removed the X-Controversial There is active debate or serious implications around merging this PR label Feb 20, 2024

alice-i-cecile added the D-Complex Quite challenging from either a design or technical perspective. Ask for help! label Feb 20, 2024

djeedai reviewed Feb 24, 2024

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pcwalton added 9 commits February 27, 2024 16:21

Merge remote-tracking branch 'origin/main' into animation-graph-asset

e7d9148

Merge remote-tracking branch 'origin/main' into animation-graph-asset

a80931a

Add transition behavior back

32791b5

Fix morph_targets example

bad1df8

Fix irradiance_volumes example

a7f8651

Fix the animated_transform example

48e89e7

Update many_foxes

9008072

Introduce an animation graph example.

1424fa1

This isn't done yet.

Use the more convenient APIs in the examples

43f5c36

pcwalton added 2 commits February 28, 2024 01:42

Add some API documentation

c70e269

Update README.md

1cda046

pcwalton added 6 commits February 28, 2024 19:35

wip

fc581f8

Flesh out the example

8a09a1d

Merge remote-tracking branch 'origin/main' into animation-graph-asset

bce3f06

Minor improvements

3982f8c

Fill out the remaining documentation

75f774f

Merge remote-tracking branch 'origin/main' into animation-graph-asset

3c1b721

pcwalton requested a review from djeedai March 1, 2024 09:27

pcwalton requested a review from mockersf March 5, 2024 05:29

pcwalton marked this pull request as ready for review March 5, 2024 05:29

rparrett and others added 2 commits March 5, 2024 16:07

Example tidying

5dcd0f9

Merge remote-tracking branch 'origin/main' into animation-graph-asset

5ba4f31

james7132 approved these changes Mar 7, 2024

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pcwalton added 4 commits March 7, 2024 01:30

Switch to Local<ThreadLocal<RefCell<AnimationGraphEvaluator>>>

64cc20a

Add #[reflect(Serialize, Debug)] to AnimationGraph

4df1de9

Switch to a BTreeMap

b8c1c47

Merge remote-tracking branch 'origin/main' into animation-graph-asset

6927108

alice-i-cecile added S-Ready-For-Final-Review This PR has been approved by the community. It's ready for a maintainer to consider merging it M-Needs-Release-Note Work that should be called out in the blog due to impact labels Mar 7, 2024

alice-i-cecile requested changes Mar 7, 2024

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Demote the warning to trace since it happens regularly when loading glTF

bf9ab8b

and is harmless, and fix the system order in the examples

alice-i-cecile approved these changes Mar 7, 2024

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alice-i-cecile added this pull request to the merge queue Mar 7, 2024

Merged via the queue into bevyengine:main with commit dfdf2b9 Mar 7, 2024
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lee-orr mentioned this pull request Mar 18, 2024

Multiple Animations on the same Mesh/Skeleton which can run Simultaneously. #6562

Closed

theredfish mentioned this pull request Mar 28, 2024

AnimationGraph: Transition with the same NodeIndex doesn't work #12604

Closed

BD103 added A-Animation Make things move and change over time and removed A-Editor Graphical tools to make Bevy games labels Jun 27, 2024

rparrett mentioned this pull request Aug 21, 2024

Add AnimationGraph::from_clips and simplify animated_fox example #14853

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Implement the `AnimationGraph`, allowing for multiple animations to be blended together. #11989

Implement the `AnimationGraph`, allowing for multiple animations to be blended together. #11989

pcwalton commented Feb 20, 2024 •

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Implement the AnimationGraph, allowing for multiple animations to be blended together. #11989

Implement the AnimationGraph, allowing for multiple animations to be blended together. #11989

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Objective

Solution

Changelog

Added

Migration Guide

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Implement the `AnimationGraph`, allowing for multiple animations to be blended together. #11989

Implement the `AnimationGraph`, allowing for multiple animations to be blended together. #11989

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