Radial Menu Control

This code provides a radial menu control node for the Godot Engine (also called a "pie menu") with support for submenus. It supports keyboard, mouse and gamepad input. You can define the basic look of the control using themes:

You can also change some menu geometry settings, such as how much of a full ring is covered by the menu, the radius and width of the ring/arc via exported properties:

A short demo video of the radial menu control is available at https://youtu.be/uATC5JfqUkI.

Setup

There are three alternative ways to set up your radial menu:

1. Activate the RadialMenu plugin in your project settings and then add a radial menu to your scene tree using the new RadialMenu node that should become available with plugin activation.

2. Preload the RadialMenu.gd Script in your script and then create a new RadialMenu via script:

# Preload the script and call it 'RadialMenu'
const RadialMenu = preload("path_to/addons/RadialMenu/RadialMenu.gd")
...
# create a radial menu
var menu = RadialMenu.new()    

3. Instance the provided RadialMenu.tscn scene in your own scene tree. The scene contains a single Popup node that has the RadialMenu.gd script attached.

Note that adding children to the RadialMenu node currently has no effect, but this may change in later versions, so do not add children to a radial menu in your scene tree if you want to make sure later versions will still work.

The radial menu control node inherits from the builtin Popup node and as such has all the behaviour of popups. This means that you must provide some code to open the popup; the radial menu is hidden by default when you run the scene.

There are three Demo scenes under addons/RadialMenu/Demo/RadialDemo[123].tscn with working radial menus, including one with submenus.

The radial menu comes preconfigured with 7 dummy entries with star icons which you must reconfigure in order to make it usable. If your menu shows 7 star items, you've forgotten to configure the menu items.

Menu items are configured as a list of dictionaries:

var items = [
   {'texture': SOME_TEXTURE, 
    'title': 'A short title', 
    'id': 'anything, really'
   },
   ...
]
# assuming that menu references your RadialMenu node...
menu.set_items(items)

The method set_items takes such a list and reconfigures the menu items. You can also manipulate the menu_items-property directly.

If the value for an item's action key is a RadialMenu node, it will be treated as a submenu and opened when the menu item is activated. See RadialDemo3.tscn for an example.

Note: Although the title key currently isn't used, it will be displayed by default in a later version, so in order to remain compatible with future versions, do provide a short title for each menu item.

Signals

A radial menu control node emits three signals:

1. item_selected(id, position)

2. item_hovered(menu_item)

3. cancelled()

The item_selected signal is emitted when a menu item is chosen and accepted via one of the supported input methods. position returns the original position at which the menu was opened via a call to open_menu.

The item_hovered signal is emitted when a menu item is selected but not yet accepted as the user's choice; for example when the mouse first hovers over it.

The cancelled signal is emitted when the user closes the menu without having made a choice.

No special signal is emitted when a submenu is openend. If you are interested in that event, you can use the about_to_show signal provided by the popup.

Configuration options

The main parameters are the menu radius (always measured from the center to the the outermost edge) and the width of the ring which holds the items. The radial menu doesn't have to be a full ring; you can also configure it as an arc. The center of the arc can sit at any angle.

Colors and some size constants such as the width of the decorator ring/arc and the selector segment can be configured via themes. See the provided light and dark themes for an example.

Public Properties

All the following properties are considered to belong to the public interface; you can acess and change these properties at will. All of these properties except menu_items are also exported by the script and can be changed directly in the Godot editor.

menu_items

A list of dictionaries containing 'texture', 'title' and 'action' keys (at least). You can also use the set_items method instead.

radius 

Sets the radius of the menu.

width

Sets the width of the ring that holds the menu items.

center_radius

Sets the radius of the center ring. If you set it to 0, the center won't be drawn.

circle_coverage : float

Determines how much of a full circle the menu covers. Must be a value between 0 and 1, though values below a certain treshold (the exact number varies depending on radius, width etc) don't make sense.

center_angle : float

Sets the angle where the center of the radial arc is located. Values are in radians. The default is -PI/2, e.g. the arc is centered at 12 o'Clock.

selector_position 

Sets the position of the selector. It's either Position.off, Position.inside (default), or Position.outside.

decorator_position

Sets the position of the decorator ring. It's either Position.off, Position.inside (default), or Position.outside.

show_animation : bool

A boolean which controls whether animations are enabled (default) or disabled.

animation_speed_factor: float

This changes the speed of the animation. Smaller values get you a faster animation. Ignored if show_animation is false.

outside_selection_factor : float

A float which determines how far beyond the ring the mouse can still select a menu item. The factor is in ring widths, so a value of 0 means the mouse won't select outside of the ring at all, and 1 means the mouse will select up to a full ring width beyond the outer edge of the ring. Defaults to 3.

icon_scale : float

Factor by which icons are scaled. This is applied to all textures provided via menu_items. Defaults to 1.

default_theme : Theme

Provides default values for colors and some constants which are used unless another active theme has entries for RadialMenu, which will override those of the default theme. Two example themes are provided; the dark one is the standard. Don't clear the default theme! You don't need to bother with the default theme property if you're providing your own theme - you can just use the theme property instead.

Public Methods

set_items(items)

Sets all menu items at once. You can also set the menu_items property directly.

open_menu(center_position: Vector2)

Opens the RadialMenu (e.g. makes it visible at the given position). Do not place the menu yourself and call show(); use this method instead.

add_icon_item(texture : Texture, title: String, id)

Adds an item represented by an icon to the menu. Note: Calling add_icon_item is less efficient than setting all items at once via set_items.

set_item_text(idx: int, title: String)

Sets the text of a single menu item. The item must exist already.

set_item_id(idx: int, id)

Sets the action of a single menu item. The item must exist already.

set_item_icon(idx: int, texture: Texture)

Sets the icon of a single menu item. The item must exist already.

select_next()

Selects the next item in clockwise order.

select_prev()

Selects the previous item in clockwise order (e.g. the next counterclockwise).

has_open_submenu()

Returns true if a submenu is active, false if not.

get_open_submenu()

Returns the submenu object if one is currently active, or null.

setup_gamepad(deviceid : int, xaxis: int, yaxis: int, deadzone: float)

Sets the gamepad device id, x-axis and y-axis that controls the radial menu. Deadzone defaults to 0.2 (e.g. 20% of the maximum).

Input handling details

The menu navigation reacts to some of the default actions Godot provides:

ui_cancel closes a submenu or the main menu without choosing an item. ui_accept accepts the currently selected choice. ui_focus_next and ui_focus_prev select items clockwise and counterclockwise. ui_down and ui_right also select clockwise, ui_up und ui_right counterclockwise.

This takes care of both the keyboard and some of the gamepad navigation.

The mouse wheel also works to select items clockwise and counterclockwise. Moving the mouse back to the center deselects any selection made in the currently active menu; moving it far beyond the menu ring/arc also deselects. You can configure the radius at which deselection happens outside the menu.

To configure gamepad input, you need to call the setup_gamepad method on every menu; the default settings let the first gamepad's two lowest-numbered axes control the item selection.

If you want to extend the RadialMenu class, you can override _input and call _radial_input(event) to get the default radial menu input handling when needed.

UI considerations

Don't pack more than a handful of items into a radial menu, especially when you don't cover the whole ring and when users use gamepads to select items, since it gets harder to select items as the selection angle narrows, and most people's brains have to actually work at processing more than, say, 5-7 items.

Also, currently stacking multiple radial submenus doesn't quite work (though it might in a later version, the code almost allows it); but this seems like a bad idea from a UI design standpoint.

Finally, if you enable the menu animation, you should provide the user with a way to turn the animation off, because it does slow down some people.

Plugin file structure

The plugin does not have any third-party dependencies. This section is provided for those who want to trim the code down to the absolute minimum number of files required.

1. You must include the LICENSE file.

2. The main work is done by the script addons/RadialMenu/RadialMenu.gd. It has several internal dependencies: drawing_library.gd and dark_default_theme.tres are required. You need to copy at least these three files into your own projects to get a working RadialMenu control. Also copy the addons/RadialMenu/icons folder or create your own. The icons inside it are referenced in the code and there is currently no way to reconfigure these except by changing the relevant constants at the top of RadialMenu.gd, but simply replacing the icons will work.

3. addons/RadialMenu/RadialMenu.tscn is optional; it is only needed if you want to create RadialMenus by instancing this scene.

4. addons/RadialMenu/radial_menu_plugin.gd and addons/RadialMenu/plugin.cfg are there for plugin initialisation if you want to use the RadialMenu control via the Godot plugin system. Otherwise they are optional.

All other files, including those under addons/RadialMenu/Demo, are optional.

Known Bugs and Caveats

This is version 1.0.0. There are bound to be bugs. Please report bugs you encounter so they can be fixed.

The RadialMenu code uses the CanvasItem drawing functions to draw the menu. Antialiased drawing seems to work more reliably on the GLES2 backend than on GLES3.

License

See the LICENSE file. The code is licensed to you under the MIT license.