Used by the editor to extend its functionality. Plugins are used by the editor to extend functionality. The most common types of plugins are those which edit a given node or resource type, import plugins and export plugins. http://docs.godotengine.org/en/3.0/development/plugins/index.html Add a control to the bottom panel (together with Output, Debug, Animation, etc). Returns a reference to the button added. It's up to you to hide/show the button when needed. If your plugin is being removed, also make sure to remove your control by calling [method remove_control_from_bottom_panel]. Add a custom control to a container (see CONTAINER_* enum). There are many locations where custom controls can be added in the editor UI. Please remember that you have to manage the visibility of your custom controls yourself (and likely hide it after adding it). If your plugin is being removed, also make sure to remove your custom controls too. Add the control to a specific dock slot (see DOCK_* enum for options). If the dock is repositioned and as long as the plugin is active, the editor will save the dock position on further sessions. If your plugin is being removed, also make sure to remove your control by calling [method remove_control_from_docks]. Add a custom type, which will appear in the list of nodes or resources. An icon can be optionally passed. When given node or resource is selected, the base type will be instanced (ie, "Spatial", "Control", "Resource"), then the script will be loaded and set to this object. You can use the [method EditorPlugin.handles] to check if your custom object is being edited by checking the script or using 'is' keyword. During run-time, this will be a simple object with a script so this function does not need to be called then. This method is called when the editor is about to save the project, switch to another tab, etc. It asks the plugin to apply any pending state changes to ensure consistency. This is used, for example, in shader editors to let the plugin know that it must apply the shader code being written by the user to the object. Clear all the state and reset the object being edited to zero. This ensures your plugin does not keep editing a currently existing node, or a node from the wrong scene. This is used for plugins that create gizmos used by the spatial editor. Just check that the node passed in the "for_spatial" argument matches your plugin. This function is used for plugins that edit specific object types (nodes or resources). It requests the editor to edit the given object. Implement this function if you are interested in 3D view screen input events. It will be called only if currently selected node is handled by your plugin. If you would like to always gets those input events then additionally use [method set_input_forwarding_always_enabled]. This is for editors that edit script based objects. You can return a list of breakpoints in the format (script:line), for example: res://path_to_script.gd:25 Get the state of your plugin editor. This is used when saving the scene (so state is kept when opening it again) and for switching tabs (so state can be restored when the tab returns). Get the undo/redo object. Most actions in the editor can be undoable, so use this object to make sure this happens when it's worth it. Get the GUI layout of the plugin. This is used to save the project's editor layout when the [method EditorPlugin.queue_save_layout] is called or the editor layout was changed(For example changing the position of a dock). Implement this function if your plugin edits a specific type of object (Resource or Node). If you return true, then you will get the functions [method EditorPlugin.edit] and [method EditorPlugin.make_visible] called when the editor requests them. Return true if this is a main screen editor plugin (it goes in the main screen selector together with 2D, 3D, Script). This function will be called when the editor is requested to become visible. It is used for plugins that edit a specific object type. Remember that you have to manage the visibility of all your editor controls manually. Queue save the project's editor layout. Remove the control from the bottom panel. Don't forget to call this if you added one, so the editor can remove it cleanly. Remove the control from the specified container. Use it when cleaning up after adding a control with [method add_control_to_container]. Note that you can simply free the control if you won't use it anymore. Remove the control from the dock. Don't forget to call this if you added one, so the editor can save the layout and remove it cleanly. Remove a custom type added by [method EditorPlugin.add_custom_type] This method is called after the editor saves the project or when it's closed. It asks the plugin to save edited external scenes/resources. Use this method if you always want to receive inputs from 3D view screen inside [method forward_spatial_gui_input]. It might be especially usable if your plugin will want to use raycast in the scene. Restore the state saved by [method EditorPlugin.get_state]. Restore the plugin GUI layout saved by [method EditorPlugin.get_window_layout]. Emitted when user change main screen view (2D, 3D, Script, AssetLib). Works also with screens which are defined by plugins. Emitted when user change scene. The argument is a root node of freshly opened scene. Emitted when user close scene. The argument is file path to a closed scene.