Skip to content

Commit

Permalink
Update export docs to use annotations
Browse files Browse the repository at this point in the history
  • Loading branch information
@vnen
vnen committed May 31, 2020
1 parent 4217e18 commit f14688e
Showing 1 changed file with 49 additions and 151 deletions.
200 changes: 49 additions & 151 deletions getting_started/scripting/gdscript/gdscript_exports.rst
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,21 +9,23 @@ Introduction to exports
In Godot, class members can be exported. This means their value gets saved along
with the resource (such as the :ref:`scene <class_PackedScene>`) they're
attached to. They will also be available for editing in the property editor.
Exporting is done by using the ``export`` keyword::
Exporting is done by using the ``@export`` annotation::

extends Button

export var number = 5 # Value will be saved and visible in the property editor.
@export var number = 5 # Value will be saved and visible in the property editor.

An exported variable must be initialized to a constant expression or have an
export hint in the form of an argument to the ``export`` keyword (see the
An exported variable must be initialized to a constant expression or have a type specifier
in the variable. Some of the export annotations have a specific type and don't need the variable to be typed (see the
*Examples* section below).

One of the fundamental benefits of exporting member variables is to have
them visible and editable in the editor. This way, artists and game designers
can modify values that later influence how the program runs. For this, a
special export syntax is provided.

Exporting can only be done with built-in types or objects derived from the :ref:`Resource class <class_Resource>`.

.. note::

Exporting properties can also be done in other languages such as C#.
Expand All @@ -37,99 +39,102 @@ Examples
# If the exported value assigns a constant or constant expression,
# the type will be inferred and used in the editor.

export var number = 5
@export var number = 5

# Export can take a basic data type as an argument, which will be
# used in the editor.
# If there's no default value, you can add a type to the variable.

export(int) var number
@export var number: int

# Export can also take a resource type to use as a hint.
# Export works with resource types.

export(Texture) var character_face
export(PackedScene) var scene_file
@export var character_face: Texture
@export var scene_file: PackedScene
# There are many resource types that can be used this way, try e.g.
# the following to list them:
export(Resource) var resource
@export var resource: Resource

# Integers and strings hint enumerated values.

# Editor will enumerate as 0, 1 and 2.
export(int, "Warrior", "Magician", "Thief") var character_class
# Editor will enumerate with string names.
export(String, "Rebecca", "Mary", "Leah") var character_name
@export_enum("Warrior", "Magician", "Thief") var character_class
# If type is String, editor will enumerate with string names.
@export_enum("Rebecca", "Mary", "Leah") var character_name: String

# Named enum values

# Editor will enumerate as THING_1, THING_2, ANOTHER_THING.
enum NamedEnum {THING_1, THING_2, ANOTHER_THING = -1}
export(NamedEnum) var x
@export var x: NamedEnum

# Strings as paths

# String is a path to a file.
export(String, FILE) var f
@export_file var f
# String is a path to a directory.
export(String, DIR) var f
@export_dir var f
# String is a path to a file, custom filter provided as hint.
export(String, FILE, "*.txt") var f
@export_file("*.txt") var f

# Using paths in the global filesystem is also possible,
# but only in scripts in "tool" mode.
# but only in scripts in tool mode.

# String is a path to a PNG file in the global filesystem.
export(String, FILE, GLOBAL, "*.png") var tool_image
@export_global_file("*.png") var tool_image
# String is a path to a directory in the global filesystem.
export(String, DIR, GLOBAL) var tool_dir
@export_global_dir var tool_dir

# The MULTILINE setting tells the editor to show a large input
# The multiline annotation tells the editor to show a large input
# field for editing over multiple lines.
export(String, MULTILINE) var text
@export_multiline var text

# Limiting editor input ranges

# Allow integer values from 0 to 20.
export(int, 20) var i
@export_range(0, 20) var i
# Allow integer values from -10 to 20.
export(int, -10, 20) var j
@export_range(-10, 20) var j
# Allow floats from -10 to 20 and snap the value to multiples of 0.2.
export(float, -10, 20, 0.2) var k
@export_range(-10, 20, 0.2) var k: float
# The limits can be only for the slider if you add the hints "or_greater" and/or "or_lesser".
@export_range(0, 100, 1, "or_greater", "or_lesser")
# Allow values 'y = exp(x)' where 'y' varies between 100 and 1000
# while snapping to steps of 20. The editor will present a
# slider for easily editing the value.
export(float, EXP, 100, 1000, 20) var l
@export_exp_range(100, 1000, 20) var l

# Floats with easing hint

# Display a visual representation of the 'ease()' function
# when editing.
export(float, EASE) var transition_speed
@export_exp_easing var transition_speed

# Colors

# Regular color given as red-green-blue-alpha value.
@export var col: Color
# Color given as red-green-blue value (alpha will always be 1).
export(Color, RGB) var col
# Color given as red-green-blue-alpha value.
export(Color, RGBA) var col
@export_color_no_alpha var col: Color

# Nodes

# Another node in the scene can be exported as a NodePath.
export(NodePath) var node_path
@export var node_path: NodePath
# Do take note that the node itself isn't being exported -
# there is one more step to call the true node:
var node = get_node(node_path)
# If you want to limit the types of nodes, you can use the @export_node_path annotation.
@export_node_path(Button, TouchScreenButton) var some_button

# Resources

export(Resource) var resource
@export var resource: Resource
# In the Inspector, you can then drag and drop a resource file
# from the FileSystem dock into the variable slot.

# Opening the inspector dropdown may result in an
# extremely long list of possible classes to create, however.
# Therefore, if you specify an extension of Resource such as:
export(AnimationNode) var resource
@export var resource: AnimationNode
# The drop-down menu will be limited to AnimationNode and all
# its inherited classes.

Expand All @@ -141,81 +146,28 @@ Exporting bit flags
-------------------

Integers used as bit flags can store multiple ``true``/``false`` (boolean)
values in one property. By using the export hint ``int, FLAGS``, they
can be set from the editor::

# Individually edit the bits of an integer.
export(int, FLAGS) var spell_elements = ELEMENT_WIND | ELEMENT_WATER
values in one property. You can use bitwise operations to combine and extract the individual bits.

Restricting the flags to a certain number of named flags is also
possible. The syntax is similar to the enumeration syntax::
The names of the flags are required::

# Set any of the given flags from the editor.
export(int, FLAGS, "Fire", "Water", "Earth", "Wind") var spell_elements = 0
@export_flags("Fire", "Water", "Earth", "Wind") var spell_elements = 0

In this example, ``Fire`` has value 1, ``Water`` has value 2, ``Earth``
has value 4 and ``Wind`` corresponds to value 8. Usually, constants
should be defined accordingly (e.g. ``const ELEMENT_WIND = 8`` and so
on).

Export hints are also provided for the physics and render layers defined in the project settings::
Export annotations are also provided for the physics and render layers defined in the project settings::

export(int, LAYERS_2D_PHYSICS) var layers_2d_physics
export(int, LAYERS_2D_RENDER) var layers_2d_render
export(int, LAYERS_3D_PHYSICS) var layers_3d_physics
export(int, LAYERS_3D_RENDER) var layers_3d_render
@export_flags_2d_physics var layers_2d_physics
@export_flags_2d_render var layers_2d_render
@export_flags_3d_physics var layers_3d_physics
@export_flags_3d_render var layers_3d_render

Using bit flags requires some understanding of bitwise operations. If in
doubt, boolean variables should be exported instead.

Exporting arrays
----------------

Exporting arrays works, but with an important caveat: while regular
arrays are created local to every class instance, exported arrays are *shared*
between all instances. This means that editing them in one instance will
cause them to change in all other instances. Exported arrays can have
initializers, but they must be constant expressions.

If the exported array specifies a type which inherits from Resource, the array
values can be set in the inspector by dragging and dropping multiple files
from the FileSystem dock at once.

::

# Exported array, shared between all instances.
# Default value must be a constant expression.

export var a = [1, 2, 3]

# Exported arrays can specify type (using the same hints as before).

export(Array, int) var ints = [1,2,3]
export(Array, int, "Red", "Green", "Blue") var enums = [2, 1, 0]
export(Array, Array, float) var two_dimensional = [[1.0, 2.0], [3.0, 4.0]]

# You can omit the default value, but then it would be null if not assigned.

export(Array) var b
export(Array, PackedScene) var scenes

# Arrays with specified types which inherit from resource can be set by
# drag-and-dropping multiple files from the FileSystem dock.

export(Array, Texture) var textures
export(Array, PackedScene) var scenes

# Typed arrays also work, only initialized empty:

export var vector3s = PackedVector3Array()
export var strings = PackedStringArray()

# Regular array, created local for every instance.
# Default value can include run-time values, but can't
# be exported.

var c = [a, 2, 3]

Setting exported variables from a tool script
---------------------------------------------

Expand Down Expand Up @@ -244,57 +196,3 @@ described in :ref:`doc_accessing_data_or_logic_from_object`.

.. warning:: The script must operate in the ``tool`` mode so the above methods
can work from within the editor.

Adding script categories
~~~~~~~~~~~~~~~~~~~~~~~~

For better visual distinguishing of properties, a special script category can be
embedded into the inspector to act as a separator. ``Script Variables`` is one
example of a built-in category.

::

func _get_property_list():
var properties = []
properties.append(
{
name = "Debug",
type = TYPE_NIL,
usage = PROPERTY_USAGE_CATEGORY | PROPERTY_USAGE_SCRIPT_VARIABLE
}
)
return properties

* ``name`` is the name of a category to be added to the inspector;

* ``PROPERTY_USAGE_CATEGORY`` indicates that the property should be treated as a
script category specifically, so the type ``TYPE_NIL`` can be ignored as it
won't be actually used for the scripting logic, yet it must be defined anyway.

Grouping properties
~~~~~~~~~~~~~~~~~~~

A list of properties with similar names can be grouped.

::

func _get_property_list():
var properties = []
properties.append({
name = "Rotate",
type = TYPE_NIL,
hint_string = "rotate_",
usage = PROPERTY_USAGE_GROUP | PROPERTY_USAGE_SCRIPT_VARIABLE
})
return properties

* ``name`` is the name of a group which is going to be displayed as collapsible
list of properties;

* every successive property added after the group property will be collapsed and
shortened as determined by the prefix defined via the ``hint_string`` key. For
instance, ``rotate_speed`` is going to be shortened to ``speed`` in this case.

* ``PROPERTY_USAGE_GROUP`` indicates that the property should be treated as a
script group specifically, so the type ``TYPE_NIL`` can be ignored as it
won't be actually used for the scripting logic, yet it must be defined anyway.

0 comments on commit f14688e

Please sign in to comment.