State-Machine-Callback

Adds a start and end callback to a state in the animator. Can be used to track when an animation state has started and ended.

How to install

This package can be installed through the Unity Package Manager with Unity version 2019.3 or greater.

Open up the package manager Window/Package Manager and click on Add package from git URL....

Paste in this repository's url.

https://github.com/Jason-Skillman/State-Machine-Callback.git

Click Add and the package will be installed in your project.

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NOTE: For Unity version 2019.2 or lower

If you are using Unity 2019.2 or lower than you will not be able to install the package with the above method. Here are a few other ways to install the package.

1. You can clone this git repository into your project's Packages folder.
2. Another alternative would be to download this package from GitHub as a zip file. Unzip and in the Package Manager click on Add package from disk... and select the package's root folder.

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Git submodule

Alternatively you can also install this package as a git submodule.

$ git submodule add https://github.com/Jason-Skillman/State-Machine-Callback.git Packages/State-Machine-Callback

How to setup

First click on the animation state in your animator. Click Add Behavior and search for the StateMachineEvent component. This component will catch events from StateMachineBehaviour and send it through the IStateMachineCallback interface.

Using the callbacks

Now that the callback behavior is attached to the animation state its time to use its callbacks. Create an empty script and attach it to the game object with the animator. Make sure that the script implements IStateMachineCallback. This will give you all of the callbacks that the StateMachineEvent component fires.

Using multible animation states

Multible animation state callbacks can be used, just attach the StateMachineEvent component to each one in the animator. In your driver script that implements IStateMachineCallback you can use the stateInfo and layerIndex parameters to separate out the animator callbacks.

In this example there are two states in the animator called TurnOn and TurnOff which both have the StateMachineEvent component. You can use stateinfo.IsName method to check which state is currently animating. This sample can also be installed by using the package manager.

public void OnAnimationStart(AnimatorStateInfo stateInfo, int layerIndex) {
	//Use stateInfo to get the correct animation state name
	if(stateInfo.IsName("TurnOn")) {
		//...
	} else if(stateInfo.IsName("TurnOff")) {
		//...
	}
}

StateMachineCallbackEvents

If you don't want to make a custom script to handle all of the different kinds of animation events then you can use the StateMachineCallbackEvents component. This component has already setup the animation events and converted them into UnityEvents for quick access. Just attach this script to the game object with an animator.

StateMachineCallbackEvents API

Member	Description
animationStateName	The name of the animation state.
layerIndex	The layer index of the animation state.

IStateMachineCallback API

Method Name	Parameters	Description
void OnAnimationStart()	stateInfo, layerIndex	Called once when the animation state starts.
void OnAnimationUpdate()	stateInfo, layerIndex	Called every frame while animating.
void OnAnimationEnd()	stateInfo, layerIndex	Called once when the animation state ends.