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Interaction System For Unity

Interaction System

"An interaction system that supports: Toggleable, Pickups, Inspectable etc. types of interactions.

Installation

Install via Git URL

You can also use the "Install from Git URL" option from Unity Package Manager to install the package.

https://github.com/Studio-23-xyz/InteractionSystem.git#upm

Install from OpenUPM:

https://openupm.com/packages/com.studio23.ss2.interactionsystem/

Usage

The samples scene contains an example setup. You will need in the scene:

  1. An InteractionManager singleton.
  2. An InteractionPromptController configured in the scene
  3. The InteractionPromptController will require an InteractionPromptModel and InteractionPromptView configured in the scene.
  4. A PlayerInteractionFinder to detect interactables in the scene.

Interactable state

Interactables can be in 3 states:

    public enum InteractionState{
        Inactive,//interaction hasn't started yet.
        Active,//runing interaction logic
        Paused,// running a sub-interaction or some other case when we don't want the interaction to run logic
    }

The CurState field returns the Interactable's current state. InteractableBase handles setting the value. So Custome Interactables inheriting from it don't need to manually set it.

SubInteractions

If you start an interaction while one is running, the old interaction is paused and the new interaction is started as a subinteraciton. When the subinteraction ends, the old interaction is resumed.

Custom Interactions

You can define your own Interactable by inheriting from InteractableBase. Be sure to use the cancelaltion token when overriding DoNormalInteraction() and DoDisabledInteraction() if you want subinteractions.

Inheritance notes:

CanBeInterrupted

If you want to push another interaction over an interaction(like dialogue during inspection),

public abstract bool CanBeInterrupted { get; }

should be overridden to true. Otherwise false.

DoNormalInteraction(CancellationToken token)

The interaction ends immediately when the DoNormalInteraction returns. Write the async function that lasts as long as the interaction should last. Ex: If you play the door opening animation, you could make the async function wait until the door is played. 

InputButton:

Pick one of the buttons in InteractionManager.Instance.InputHandler

public override InputButtonSlot InputButton => InteractionManager.Instance.InputHandler.ToggleButton;

Setup Functions

  1. Interaction.HandleInteractionStarted()

  2. Interaction.HandleInteractionResumed()

  3. Interaction.HandleInteractionPause()

  4. Interaction.HandleInteractionCompleted()

Multiple interactions on same object depending on conditions:

Add InteractionConditions to the InteractionConditions list in the InteractableBase monobehavior. Interaction System goes through all Interactables in a given gameobject and picks the first interactable whose conditions return InteractionConditionResult.Show. The Interactable component order on the gameobject affects this.

Additionally if the Interactable is not enabled, it is skipped. So you can control which interactable gets picked by disabling them.

This may be overhauled in the future.

Example:

We want to open the door if the player has the key, Otherwise we want to play a locked door rattling animation

Solution:

Make two interactables. One for opening. One for the locked door rattling interaction. Put both on same door object.

On the open door interaction, add a InteractionCondition that returns InteractionConditionResult.show if the player has the key.

No need for any conditions on the locked door interaction. It will be the "default" interaction. However, the component order should come after the open door interaction.

Interaction conditions notes:

InteractionConditions return an InteractionConditionResult result with 3 values:

  1. Show: Shows the prompt  for the interactable when this result is returned

  2. Hide: Hides the prompt for the interactable when this result is returned

  3. Passthrough: Defers to next InteractionCondition in list when this result is returned. If this is the last InteractionCondition in the list, the final result becomes InteractionConditionResult.Hide  Ex: If Interaction1, Interaction2 is in list, and Interaction1 returns Passthrough

    1. If interaction2 returns Show or Hide, the final result is show or hide accordingly

    2. If interaction2 returns Passthrough, the final result is Hide.

You can write your own InteractionCondition in SS2 implementing the InteractionCondition class.

Gotchas

  1. Be sure to use the cancellation token . Otherwise interrupt will not work

  2. DoNormalInteraction() can be called multiple times if the interaction can be interrupted.

    1. Flow:

      1. Interaction.HandleInteractionStarted()

      2. Interaction.DoNormalInteraction()

      3. Interrupt happens by starting a sub interaction

      4. Interaction.HandleInteractionPause()

      5. SubInteraction.HandleInteractionStarted()

      6. SubInteraction.DoNormalInteraction()

      7. Assuming the SubInteraction runs until completion

      8. SubInteraction.HandleInteractionCompleted()

      9. Interaction.HandleInteractionResumed()

      10. Interaction.DoNormalInteraction()

      11. Assuming this time Interaction runs until completion

      12. Interaction.HandleInteractionCompleted()

    2. Do your setup work in HandleInteractionStarted() and HandleInteractionResumed()

    3. Ensure that there is no issue if DoNormalInteraction is called multiple times and can be cancelled.

  3. You don't have to worry about interrupt if you override CanBeInterrupted to false.

Finding and showing Interactions

The PlayerInteractionFinder class raycasts through the scene to detect interactables. The _interactionLayerMask field controls which layers it checks. To show them:

var interactables = _interactionFinder.FindInteractables();
InteractionManager.Instance.ShowNewInteractables(interactables);

Starting interactions

InteractionPromptController handles hold confirmation and starting interation.. The InteractionManager will automatically start a confirmation once the InteractionPromptController confirms one.

Hold interactions

If the _interactionHoldTime field on the interactable is > 0, then the InteractionPromptController will require holding the button for that amount of time.

You have to tell the InteractionManager to start the interaction:

Changing the text shown in the InteractionPrompt for an interactable

Override the following functions:

  /// <summary>
  /// Interaction prompt prefix(ex: "Inspect")
  /// </summary>
  /// <returns></returns>
  public abstract string GetPromptPrefix();
  /// <summary>
  /// Interaction prompt suffix that appears after the prompt
  /// </summary>
  /// <returns></returns>
  public abstract string GetPromptSuffix();
  /// <summary>

Custom Interaction Prompt UI

You can inherit from the InteractionPromptView class to customize the Prompt UI.

Knowing when Interaction starts/ends

InteractionManager fires the following events to tell you that

        /// <summary>
        /// Fired when we start the first interaction on the stack
        /// Not fired when subinteractions are started 
        /// </summary>
        public event Action OnInteractionChainStarted;
        /// <summary>
        /// Fired when we complete all the interactions on the stack
        /// Or when we cancel the interaction confirmation without anything in the stack
        /// Not fired when subinteractions are completed
        /// </summary>
        public event Action OnInteractionChainEnded;
        public bool IsRunningInteraction{get;}

InteractionManager.IsRunningInteraction can also be used to synchronously check if an interaction is running

Camera Stacking is removed

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