godot-plugin-interop

A snippet of code for enabling interoperability between plugins. Allows plugins to get the object of another plugin which registered itself or to broadcast notifications with arguments.

Installation

• Copy the files in this repository into your plugin. It's best practice to have a folder just for the files of the interop, but it's not required.

Usage

In your plugin, preload the class and register / deregister your plugin. Note that the first argument must be your plugin for each interop function call.

var Interop = preload("path/to/interop.gd")

# Enable and disable as your plugin is added or removed from the tree:

func _enter_tree() -> void:
    # Change the string to anything that identifies your plugin
    Interop.register(self, "custom_plugin_identifier")
    ...

func _exit_tree() -> void:
    Interop.deregister(self) 
    ...

Make use of it elsewhere:

    # For example in the input handling method:
    if event.pressed and is_selecting():
        # Change string here too. my_plugin can be self if called from main script.
        var other_plugin = Interop.get_plugin_or_null(my_plugin, "name_of_other_plugin")
        if other_plugin and other_plugin.state != 15:
            return

To receive notifications from other plugins, declare this in your plugin:

func _interop_notification(caller_plugin: String, code: int, id: String, args):
    ... # Do something based on the arguments

The arguments depend on the notification code. See below.

Emitting and consuming work state

Plugins can tell every other plugin that they started or ended work. Other plugins can make decisions based on this:

func start()
    # Notifies other plugins that you started something. The custom_arguments value is optional.
    Interop.start_work(self, "name_of_work", custom_arguments)
    ...

func commit()
    # Always have this paired with start_work() with the same string. The custom_arguments value is optional.
    Interop.end_work(self, "name_of_work", custom_arguments)
    ...

You can request other plugins to not access input for a while:

    # Plugins that respect this call will not do anything when a key is pressed or the mouse is moved
    # or its button is clicked.
    Interop.grab_full_input(self)
    
    ...
    
    # Make sure to call this somewhere later:
    Interop.release_full_input(self)

Handling the notifications:

Plugins can consume notifications via the optional _interop_notification virtual function. The code argument is the code of the notification (see below). The id and args depend on the code and the plugin sending the notification. See their respective documentation.

func _interop_notification(caller_plugin_id: String, code: int, id: String, args):
    match code:
        Interop.NOTIFY_CODE_WORK_STARTED:
            match id:
                "plugin_transform": # Custom id from the caller plugin.
                    toolbar.toggle_plugin_buttons(false)
        Interop.NOTIFY_CODE_WORK_ENDED:
            match id:
                "plugin_transform": # Custom id from the caller plugin.
                    toolbar.toggle_plugin_buttons(true)

Builtin notification codes:

Notification when a plugin starts doing work which will be in progress until NOTIFY_CODE_WORK_ENDED notification is received.
The id argument should be identifying the work started. See documentation of the interoperating plugins for the values of id and args (optional).
const NOTIFY_CODE_WORK_STARTED = 1

Notification when a plugin finished a work that was in progress after you received NOTIFY_CODE_WORK_STARTED.
The id argument should be identifying the work that's ending. See documentation of the interoperating plugins for the values of id and args (optional).
const NOTIFY_CODE_WORK_ENDED = 2

Notification when a plugin requests every other plugin to not react to input. Should be followed by NOTIFY_CODE_ALLOW_INPUT.
No id or args apply. They will be empty or null.
const NOTIFY_CODE_REQUEST_IGNORE_INPUT = 3

Notification when a plugin stops requesting every other plugin to not react to input.
No id or args apply. They will be empty or null.
const NOTIFY_CODE_ALLOW_INPUT = 4

Custom plugin notifications:

You can define any value as notification code in your plugin. To be tidy and not clash with the notification codes of the interop script, define your codes as a combination of NOTIFY_CODE_USER and a value like this:

const MY_NOTIFY_CODE = Interop.NOTIFY_CODE_USER + 0
const MY_SECOND_NOTIFY_CODE = Interop.NOTIFY_CODE_USER + 1

To broadcast a notification, write:

    # This is just an example. Use your codes, id strings, and arguments.
    # Both the id and arguments are optional.
    Interop.notify_plugins(self, MY_NOTIFY_CODE, "my_custom_id_string", [1, 2, some_value])

You can then include a list of your code constants in your documentation for other plugins to use. Don't forget to mention the value of id and args if you use them.