Merge pull request #49094 from madmiraal/fix-docs-3977

Update EditorResourcePreview queue_*() documentation

doc/classes/EditorResourcePreview.xml

@@ -40,7 +40,8 @@
  <argument index="3" name="userdata" type="Variant">
  </argument>
  <description>
- Queue a resource being edited for preview (using an instance). Once the preview is ready, your receiver.receiver_func will be called either containing the preview texture or an empty texture (if no preview was possible). Callback must have the format: (path,texture,userdata). Userdata can be anything.
+ Queue the [code]resource[/code] being edited for preview. Once the preview is ready, the [code]receiver[/code]'s [code]receiver_func[/code] will be called. The [code]receiver_func[/code] must take the following four arguments: [String] path, [Texture2D] preview, [Texture2D] thumbnail_preview, [Variant] userdata. [code]userdata[/code] can be anything, and will be returned when [code]receiver_func[/code] is called.
+ [b]Note[/b]: If it was not possible to create the preview the [code]receiver_func[/code] will still be called, but the preview will be null.
  </description>
  </method>
  <method name="queue_resource_preview">
@@ -55,7 +56,8 @@
  <argument index="3" name="userdata" type="Variant">
  </argument>
  <description>
- Queue a resource file for preview (using a path). Once the preview is ready, your receiver.receiver_func will be called either containing the preview texture or an empty texture (if no preview was possible). Callback must have the format: (path,texture,userdata). Userdata can be anything.
+ Queue a resource file located at [code]path[/code] for preview. Once the preview is ready, the [code]receiver[/code]'s [code]receiver_func[/code] will be called. The [code]receiver_func[/code] must take the following four arguments: [String] path, [Texture2D] preview, [Texture2D] thumbnail_preview, [Variant] userdata. [code]userdata[/code] can be anything, and will be returned when [code]receiver_func[/code] is called.
+ [b]Note[/b]: If it was not possible to create the preview the [code]receiver_func[/code] will still be called, but the preview will be null.
  </description>
  </method>
  <method name="remove_preview_generator">

editor/editor_resource_preview.h

@@ -101,7 +101,8 @@ class EditorResourcePreview : public Node {
 public:
  static EditorResourcePreview *get_singleton();
 
- //callback function is callback(String p_path,Ref<Texture2D> preview,Variant udata) preview null if could not load
+ // p_receiver_func callback has signature (String p_path, Ref<Texture2D> p_preview, Ref<Texture2D> p_preview_small, Variant p_userdata)
+ // p_preview will be null if there was an error
  void queue_resource_preview(const String &p_path, Object *p_receiver, const StringName &p_receiver_func, const Variant &p_userdata);
  void queue_edited_resource_preview(const Ref<Resource> &p_res, Object *p_receiver, const StringName &p_receiver_func, const Variant &p_userdata);