Add C# Export page for 3.4 branch

getting_started/scripting/c_sharp/c_sharp_exports.rst

@@ -0,0 +1,365 @@
+.. _doc_c_sharp_exports:
+
+C# Exports
+==========
+
+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]`` attribute.
+
+.. code-block:: csharp
+
+    public class ExportExample : Spatial
+    {
+        [Export]
+        private int Number = 5;
+    }
+    
+In that example the value ``5`` will be saved, and after building the current project
+it will be visible in the property 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 GDScript, for information on that
+    see :ref:`doc_gdscript_exports`.
+
+Basic use
+---------
+
+Exporting can work with and without setting a default value. For int and float
+``0`` will then be used as the default.
+
+.. code-block:: csharp
+
+    [Export]
+    private int Number;
+
+Export works with resource types.
+
+.. code-block:: csharp
+
+    [Export]
+    private Texture CharacterFace;
+    [Export]
+    private PackedScene SceneFile;
+
+There are many resource types that can be used this way, try e.g.
+the following to list them:
+
+.. code-block:: csharp
+
+    [Export]
+    private Resource Resource;
+
+.. 
+	Commenting out enum examples becuase I have been told they
+	require extra steps to actually work properly. The examples bellow
+	will show up in the inspector but apparently do not function properly
+..
+	Integers and strings hint enumerated values.
+..
+	code-block:: csharp
+..
+	    // Editor will enumerate as 0, 1 and 2.
+	    [Export(PropertyHint.Enum, "Warrior,Magician,Thief")]
+	    private int CharacterClass;
+..
+	If type is String, editor will enumerate with string names.
+..
+	code-block:: csharp
+..
+	    [Export(PropertyHint.Enum, "Rebecca,Mary,Leah")]
+	    private string CharacterName;
+..
+	Named enum values
+	-----------------
+..
+	Editor will enumerate as THING_1, THING_2, ANOTHER_THING.
+..
+	code-block:: csharp
+..
+	    private enum NamedEnum
+	    {
+	        Thing1,
+	        Thing2,
+	        AnotherThing = -1
+	    }
+	    [Export(PropertyHint.Enum)]
+	    private NamedEnum X;
+
+Strings as paths
+----------------
+
+Property hints can be used to export strings as paths
+
+String as a path to a file.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.File)]
+    private string GameFile;
+
+String as a path to a directory.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.Dir)]
+    private string GameDirectory;
+
+String as a path to a file, custom filter provided as hint.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.File, "*.txt,")]
+    private string GameFile;
+
+Using paths in the global filesystem is also possible,
+but only in scripts in tool mode.
+
+String as a path to a PNG file in the global filesystem.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.GlobalFile, "*.png")]
+    private string ToolImage;
+
+String as a path to a directory in the global filesystem.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.GlobalDir)]
+    private string ToolDir;
+
+The multiline annotation tells the editor to show a large input
+field for editing over multiple lines.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.MultilineText)]
+    private string Text;
+
+Limiting editor input ranges
+----------------------------
+
+Using the range property hint allows you to limit what can be
+input as a value using the editor.
+
+Allow integer values from 0 to 20.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.Range, "0,20,")]
+    private int Number;
+
+Allow integer values from -10 to 20.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.Range, "-10,20,")]
+    private int Number;
+
+Allow floats from -10 to 20 and snap the value to multiples of 0.2.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.Range, "-10,20,0.2")]
+    private float Number;
+
+If you add the hints "or_greater" and/or "or_lesser" you can go above
+or below the limits when adjusting the value by typing it instead of using
+the slider.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.Range, "0,100,1,or_greater,or_lesser")]
+    private int Number;
+
+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. This only works with floats.
+	
+.. code-block:: csharp
+
+    [Export(PropertyHint.ExpRange, "100,1000,20")]
+    private float Number;
+
+Floats with easing hint
+-----------------------
+
+Display a visual representation of the 'ease()' function
+when editing.
+	
+.. code-block:: csharp
+
+    [Export(PropertyHint.ExpEasing)]
+    private float TransitionSpeed;
+
+Colors
+------
+
+Regular color given as red-green-blue-alpha value.
+
+.. code-block:: csharp
+
+    [Export]
+    private Color Col;
+
+Color given as red-green-blue value (alpha will always be 1).
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.ColorNoAlpha)]
+    private Color Col;
+
+Nodes
+-----
+
+Nodes can't be directly exported. Instead you need to export
+a node path, then use that node path with ``GetNode()``.
+
+.. code-block:: csharp
+
+    [Export]
+    private NodePath MyNodePath;
+    private Label MyNode;
+
+    public override void _Ready()
+    {   
+        MyNode = GetNode<Label>(MyNodePath);
+    }
+
+Resources
+---------
+
+.. code-block:: csharp
+
+    [Export]
+    private 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:
+
+.. code-block:: csharp
+
+    [Export]
+    private AnimationNode Resource;
+
+The drop-down menu will be limited to AnimationNode and all
+its inherited classes.
+
+It must be noted that even if the script is not being run while in the
+editor, the exported properties are still editable. This can be used
+in conjunction with a :ref:`script in "tool" mode <doc_gdscript_tool_mode>`.
+
+Exporting bit flags
+-------------------
+
+Integers used as bit flags can store multiple ``true``/``false`` (boolean)
+values in one property. By using the ``Flags`` property hint, they
+can be set from the editor.
+
+.. code-block:: csharp
+
+    // Set any of the given flags from the editor.
+    [Export(PropertyHint.Flags, "Fire,Water,Earth,Wind")]
+    private int SpellElements = 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.
+``private const int ElementWind = 8`` and so on).
+
+Export annotations are also provided for the physics and render layers defined in the project settings.
+
+.. code-block:: csharp
+
+    [Export(PropertyHint.Layers2dPhysics)]
+    private int Layers2dPhysics;
+    [Export(PropertyHint.Layers2dRender)]
+    private int Layers2dRender;
+    [Export(PropertyHint.Layers3dPhysics)]
+    private int layers3dPhysics;
+    [Export(PropertyHint.Layers3dRender)]
+    private int layers3dRender;
+
+Using bit flags requires some understanding of bitwise operations.
+If in doubt, use boolean variables instead.
+
+Exporting arrays
+----------------
+
+Exported arrays should be initialized empty.
+
+.. code-block:: csharp
+
+    [Export]
+    private Vector3[] Vector3s = new Vector3[0];
+    [Export]
+    private String[] String = new String[0];
+
+
+You can omit the default value, but then it would be null if not assigned.
+
+.. code-block:: csharp
+
+    [Export]
+    private int[] Numbers;
+
+Arrays with specified types which inherit from resource can be set by
+drag-and-dropping multiple files from the FileSystem dock.
+
+.. code-block:: csharp
+
+    [Export]
+    private Texture[] Textures;
+    [Export]
+    private PackedScene[] Scenes;
+
+Arrays where the default value includes run-time values can't
+be exported.
+
+.. code-block:: csharp
+
+    private int Number = 1;
+    private int[] SeveralNumbers = {Number,2,3};
+
+Setting exported variables from a tool script
+---------------------------------------------
+
+When changing an exported variable's value from a script in
+:ref:`doc_gdscript_tool_mode`, the value in the inspector won't be updated
+automatically. To update it, call
+:ref:`property_list_changed_notify() <class_Object_method_property_list_changed_notify>`
+after setting the exported variable's value.
+
+Advanced exports
+----------------
+
+Not every type of export can be provided on the level of the language itself to
+avoid unnecessary design complexity. The following describes some more or less
+common exporting features which can be implemented with a low-level API.
+
+Before reading further, you should get familiar with the way properties are
+handled and how they can be customized with
+:ref:`_set() <class_Object_method__get_property_list>`,
+:ref:`_get() <class_Object_method__get_property_list>`, and
+:ref:`_get_property_list() <class_Object_method__get_property_list>` methods as
+described in :ref:`doc_accessing_data_or_logic_from_object`.
+
+.. seealso:: For binding properties using the above methods in C++, see
+             :ref:`doc_binding_properties_using_set_get_property_list`.
+
+.. warning:: The script must operate in the ``tool`` mode so the above methods
+             can work from within the editor.

getting_started/scripting/c_sharp/index.rst

@@ -8,4 +8,5 @@ C#
    c_sharp_basics
    c_sharp_features
    c_sharp_differences
+   c_sharp_exports
    c_sharp_style_guide

getting_started/scripting/gdscript/gdscript_exports.rst

@@ -27,7 +27,8 @@ special export syntax is provided.
 .. note::
 
     Exporting properties can also be done in other languages such as C#.
-    The syntax varies depending on the language.
+    The syntax varies depending on the language. See :ref:`doc_c_sharp_exports`
+    for information on C# exports.
 
 Examples
 --------