Godot Triggers

An attempt to bring Source-like triggers and outputs in Godot, albeit in a limited state.

Usage

1. Simply drag and drop the Trigger2D/Trigger3D into your scene and give it a CollisionShape2D/3D.
2. IMPORTANT: Set the collision mask of the trigger! Any areas/bodies in the layer it scans will activate the trigger. The collision layer of the trigger itself has no effect.
3. Add the outputs in the Inspector tab.

The output system

The way outputs are handled are, as the description says, similar to how the Source engine handles outputs. Here, Outputs are Resources that contain five variables. They ultimately just describe what method (and additional arguments) to call on a Node.

Note that the Triggers have assertions for output, target and target_method.

By default, the Triggers only support four outputs:

• area_entered/body_entered
• area_exited/body_exited

You can, however, extend the trigger to add more outputs.

Adding custom outputs

In this section we will add the output "interacted" that will be fired when the player is in the trigger and presses the ui_accept button (spacebar).

1. Make a new array to store your custom outputs. (`_on_interacted_outputs)
2. Add Outputs via the _ready() method.

func _ready() -> void:
    super._ready()
    
    for _output: Output in outputs:
        if _output.output == "interacted":
            _on_interacted_outputs.append(_output)

3. In your code for checking input and player collisions, add _emit_outputs(_on_interacted_outputs).

Adding outputs via code

This is mostly useful for when you're extending the Trigger script for more specific uses. Here is a direct example from my game, which targets a specified "target location" Node, which has a method that essentially sets the player's global position to its global position.

func _ready() -> void:
    super._ready()
    
    var output: Output = Output.new()
    output.target = tele_target.get_path()
    output.target_method = "teleport"
    
    _on_area_entered_outputs.append(output)

Known limitations

• Source's outputs have refires. This one does not.
• There are also no special targetnames unlike in Source, where you can call !activator to, I don't know, deal 10000 damage to the players that touch it during a Payload explosion or something. Wildcards are also a no-go (setup_door_* to call setup_door_top and setup_door_bottom). This is because the target in Outputs require a NodePath, rather than a simple string name.
• There are no ways to view all the outputs fired onto a Node, unlike Source.