#bevy #animation #sprite #action #atlas


Action-based animation system

1 unstable release

0.1.0 Apr 8, 2023

#1440 in Game dev


293 lines


Action-based animation system for Bevy.


This plugin provides users of the Bevy game engine with an action/trigger-based animation system. This kind of animation system makes for a more scalable framework for adding animations into a game, by providing the necessary tools to decouple animation logic from game logic.

This plugin is based on bevy_action.

WARNING: This plugin is still in beta state. Please report bugs on the issues page!

How It Works


Based on bevy_action, animations are configured tightly with specific action types defined by the user, and are triggered when the AnimationPlugin's internal systems read an action that corresponds to one of its defined animations.

Animation Queue

bevy_action_animation is a fairly simple plugin. It provides the action-based animation system by using an animation queue.

This queue queues up animations as they are triggered, and plays them in order as they pop off the queue (LIFO).

There are two types of animation-play modes: Once, and Repeating.

The Once mode plays the animation clip entirely, once, and cannot be interrupted.

The Repeating mode plays in a cycle, infinitely, until another animation is added to the animation queue. This means that if a Repeating animation was added, and then another was added the next frame, the original Repeating animation would most likely only play one frame before being cancelled and overwritten by the next animation.

Animation Attributes

Another feature of bevy_action_animation is the ability to give certain animations certain attributes. These are hard-defined by the plugin itself, and include the following:

  • FlipX (flips sprite horizontally)
  • FlipY (flips sprite vertically)
  • Trigger(Action) (triggers an action upon completion) [1]


  1. Once animations will trigger a Trigger attribute's action upon full completion. Repeating animations will trigger the attribute's action upon cancellation.

Duplicating these attributes is possible, but may have no affect for some:

  • FlipX - No affect
  • FlipY - No affect
  • Trigger - Adds another trigger

Animation Definition File

Animations are defined in RON files.

NOTE: Custom formats will be supported in the future.

An example of the format structure of the RON files is available in the assets directory.


See the examples directory.

Future Work

  • Better documentation
  • Support custom formats
  • Decouple animation files from the animation system
  • Migrate away from rand for RNG (once Bevy offers an RNG API)
  • Benchmark?


~1M SLoC