GDScript 导出

导出简介

在Godot中,可以导出类成员。这意味着它们的值会与它们所附加的资源(例如 scene)一起保存。它们也可以在属性编辑器中进行编辑。导出使用关键字 export 来完成:

extends Button

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

export 关键字后,导出的变量必须初始化为常量表达式,或者具有使用的参数形式的导出提示(请参见下面的 示例 部分)。

导出成员变量的基本好处之一是使它们在编辑器中可见并可编辑。这样,美术师和游戏设计师可以修改值,这些值以后会影响程序的运行方式。为此,提供了一种特殊的导出语法。

注解

导出属性也可以使用其他语言(例如C#)来完成。语法因语言而异。

示例

# 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 can take a basic data type as an argument, which will be
# used in the editor.

export(int) var number

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

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

# 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

# Strings as paths

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

# Using paths in the global filesystem is also possible,
# 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
# String is a path to a directory in the global filesystem.
export(String, DIR, GLOBAL) var tool_dir

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

# Limiting editor input ranges

# Allow integer values from 0 to 20.
export(int, 20) var i
# Allow integer values from -10 to 20.
export(int, -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
# 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

# Floats with easing hint

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

# Colors

# 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

# Nodes

# Another node in the scene can be exported as a NodePath.
export(NodePath) var node_path
# 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)

# Resources

export(Resource) var 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
# The drop-down menu will be limited to AnimationNode and all
# its inherited classes.

必须注意,即使在编辑器中未运行脚本,导出的属性仍可编辑。可以与 使用工具模式的脚本 结合使用。

导出位标志

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:

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

You must provide a string description for each flag. 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(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

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

导出数组

导出的数组可以具有初始化器,但是它们必须是常量表达式。

如果导出的数组指定了从Resource继承的类型,则可以通过一次从FileSystem扩展坞中拖放多个文件来在检查器中设置数组值。

# 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 = PoolVector3Array()
export var strings = PoolStringArray()

# Default value can include run-time values, but can't
# be exported.

var c = [a, 2, 3]

Setting exported variables from a tool script

工具模式 下的脚本中,更改一个导出变量的值时,属性检查器中对应的值不会自动更新。要更新它,请在设置导出变量的值之后,调用 property_list_changed_notify()

Advanced exports

为了避免不必要的复杂设计,不是所有导出类型都在语言层面上提供。下面将说明一些能用底层API实现的,较为常见的导出方法。

在继续阅读之前,你应该了解引擎是如何处理属性的,以及如何用 _set()_get(),以及 _get_property_list() 方法来自定义属性。详情可参阅 从对象访问数据或逻辑

参见

要用上述方法绑定属性,参阅 使用 _set/_get/_get_property_list 绑定属性

警告

脚本必须在 tool 模式运行,上述方法才能在编辑器内运行。

Adding script categories

为了在视觉上更好区分各个属性,可以将特殊的脚本分类作为作为分割线嵌入编辑器。Script Variables 就是一种内建分类。

func _get_property_list():
    var properties = []
    properties.append(
        {
            name = "Debug",
            type = TYPE_NIL,
            usage = PROPERTY_USAGE_CATEGORY | PROPERTY_USAGE_SCRIPT_VARIABLE
        }
    )
    return properties
  • name 是要加入属性面板中的分类的名字;
  • PROPERTY_USAGE_CATEGORY 表明了该属性应被视为一个脚本分类,因此可以忽略 TYPE_NIL 这个类型,因为它其实并没有被脚本逻辑所处理。但无论如何,你还是要在这儿定义它。

Grouping properties

名称类似的属性们可以添加为一组。

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 是包含了一组属性的可折叠群组的名称;
  • 接下来所有新增的属性都会被放在该群组中,通过 hint_string 字典键定义为可折叠,并以其为前缀缩写名称。例如,本例中的``rotate_speed`` 将会被缩写为 speed
  • PROPERTY_USAGE_GROUP 表明了该属性应被视为一个脚本分类,因此可以忽略 TYPE_NIL 这个类型,因为它其实并没有被脚本逻辑所处理。但无论如何,你还是要在这儿定义它。