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:

  1. extends Button
  3. 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

  1. # If the exported value assigns a constant or constant expression,
  2. # the type will be inferred and used in the editor.
  4. export var number = 5
  6. # Export can take a basic data type as an argument, which will be
  7. # used in the editor.
  9. export(int) var number
  11. # Export can also take a resource type to use as a hint.
  13. export(Texture) var character_face
  14. export(PackedScene) var scene_file
  15. # There are many resource types that can be used this way, try e.g.
  16. # the following to list them:
  17. export(Resource) var resource
  19. # Integers and strings hint enumerated values.
  21. # Editor will enumerate as 0, 1 and 2.
  22. export(int, "Warrior", "Magician", "Thief") var character_class
  23. # Editor will enumerate with string names.
  24. export(String, "Rebecca", "Mary", "Leah") var character_name
  26. # Named enum values
  28. # Editor will enumerate as THING_1, THING_2, ANOTHER_THING.
  29. enum NamedEnum {THING_1, THING_2, ANOTHER_THING = -1}
  30. export(NamedEnum) var x
  32. # Strings as paths
  34. # String is a path to a file.
  35. export(String, FILE) var f
  36. # String is a path to a directory.
  37. export(String, DIR) var f
  38. # String is a path to a file, custom filter provided as hint.
  39. export(String, FILE, "*.txt") var f
  41. # Using paths in the global filesystem is also possible,
  42. # but only in scripts in "tool" mode.
  44. # String is a path to a PNG file in the global filesystem.
  45. export(String, FILE, GLOBAL, "*.png") var tool_image
  46. # String is a path to a directory in the global filesystem.
  47. export(String, DIR, GLOBAL) var tool_dir
  49. # The MULTILINE setting tells the editor to show a large input
  50. # field for editing over multiple lines.
  51. export(String, MULTILINE) var text
  53. # Limiting editor input ranges
  55. # Allow integer values from 0 to 20.
  56. export(int, 20) var i
  57. # Allow integer values from -10 to 20.
  58. export(int, -10, 20) var j
  59. # Allow floats from -10 to 20 and snap the value to multiples of 0.2.
  60. export(float, -10, 20, 0.2) var k
  61. # Allow values 'y = exp(x)' where 'y' varies between 100 and 1000
  62. # while snapping to steps of 20. The editor will present a
  63. # slider for easily editing the value.
  64. export(float, EXP, 100, 1000, 20) var l
  66. # Floats with easing hint
  68. # Display a visual representation of the 'ease()' function
  69. # when editing.
  70. export(float, EASE) var transition_speed
  72. # Colors
  74. # Color given as red-green-blue value (alpha will always be 1).
  75. export(Color, RGB) var col
  76. # Color given as red-green-blue-alpha value.
  77. export(Color, RGBA) var col
  79. # Nodes
  81. # Another node in the scene can be exported as a NodePath.
  82. export(NodePath) var node_path
  83. # Do take note that the node itself isn't being exported -
  84. # there is one more step to call the true node:
  85. var node = get_node(node_path)
  87. # Resources
  89. export(Resource) var resource
  90. # In the Inspector, you can then drag and drop a resource file
  91. # from the FileSystem dock into the variable slot.
  93. # Opening the inspector dropdown may result in an
  94. # extremely long list of possible classes to create, however.
  95. # Therefore, if you specify an extension of Resource such as:
  96. export(AnimationNode) var resource
  97. # The drop-down menu will be limited to AnimationNode and all
  98. # 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

用作位标志的整数可以在一个属性中存储多个 true/ false (布尔值)值.通过使用导出提示 int, FLAGS ,可以从属性检查器中设置它们:

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

你必须为每个标志提供一个字符串描述.在这个例子中, 火(Fire) 的值是1, 水(Water) 的值是2, 土(Earth) 的值是4, 风(Wind) 对应的值是8.通常,应相应地定义常量(例如 const ELEMENT_WIND = 8 等等).

也可以为项目设置中定义的物理层和渲染层提供导出提示:

  1. export(int, LAYERS_2D_PHYSICS) var layers_2d_physics
  2. export(int, LAYERS_2D_RENDER) var layers_2d_render
  3. export(int, LAYERS_3D_PHYSICS) var layers_3d_physics
  4. export(int, LAYERS_3D_RENDER) var layers_3d_render

使用位标志需要对位操作有一定的了解.如果有疑问,请使用布尔变量代替.

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.

  1. # Default value must be a constant expression.
  3. export var a = [1, 2, 3]
  5. # Exported arrays can specify type (using the same hints as before).
  7. export(Array, int) var ints = [1, 2, 3]
  8. export(Array, int, "Red", "Green", "Blue") var enums = [2, 1, 0]
  9. export(Array, Array, float) var two_dimensional = [[1.0, 2.0], [3.0, 4.0]]
  11. # You can omit the default value, but then it would be null if not assigned.
  13. export(Array) var b
  14. export(Array, PackedScene) var scenes
  16. # Arrays with specified types which inherit from resource can be set by
  17. # drag-and-dropping multiple files from the FileSystem dock.
  19. export(Array, Texture) var textures
  20. export(Array, PackedScene) var scenes
  22. # Typed arrays also work, only initialized empty:
  24. export var vector3s = PoolVector3Array()
  25. export var strings = PoolStringArray()
  27. # Default value can include run-time values, but can't
  28. # be exported.
  30. var c = [a, 2, 3]

从工具脚本设置导出变量

在 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() .

导出进阶

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.

在进一步阅读前,你需要熟悉属性(properties)的运作方式和它们是如何通过 _set() 、 _get() 以及 _get_property_list() 方式进行定制的.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.

对脚本中的属性添加类别

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分割线嵌入属性检查器.``Script Variables`` 就是一种内建分类.

  1. func _get_property_list():
  2.     var properties = []
  3.     properties.append(
  4.         {
  5.             name = "Debug",
  6.             type = TYPE_NIL,
  7.             usage = PROPERTY_USAGE_CATEGORY | PROPERTY_USAGE_SCRIPT_VARIABLE
  8.         }
  9.     )
  10.     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.

对属性进行分组

名称类似的属性们可以添加为一组.

  1. func _get_property_list():
  2.     var properties = []
  3.     properties.append({
  4.             name = "Rotate",
  5.             type = TYPE_NIL,
  6.             hint_string = "rotate_",
  7.             usage = PROPERTY_USAGE_GROUP | PROPERTY_USAGE_SCRIPT_VARIABLE
  8.     })
  9.     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.