Add type filters to AnimationPlayer's "Add Track"

[jasonmorgado]

(My first contribution btw)

Adds type filters to the SceneTreeDialogs that come from AnimationPlayer's "Add Track" button.
The Add Track button has several types of tracks that require specific node types, but currently present a full SceneTreeDialog, and throw an error if you provide the wrong type.

Fixes #55944 which describes this issue specifically for Audio tracks.

The SceneTreeDialog that appears when Add Track > Audio Playback Track is selected. Now with the correct filters!

• Property, Call Method, Bezier Curve have no filters
• Blend Shape has a Meshinstance3D filter
• 3D Position, Rotation, Scale tracks have a Node3D filter
• Audio has AudioStreamPlayer(2D/3D) filter
• Animation has AnimationPlayer filter

I've tested the SceneTreeDialog in the inspector (export nodepath), works the same as usual. However, I'm not sure where else to find the prompts for the SceneTreeDialog in the editor for further testing.
I see it's in a few different places in the code such as:

• EditorInterface
• EditorPropertyNodePath (The one I tested)
• MultiMeshEditor
• Particles3DEditorPlugin
• ReplicationEditor
  All these examples set filters once after creating the dialog, so they should be unaffected.

---

Related, I did notice the SceneTreeDialog's set_valid_types was not set up correctly to be called on the same instance of SceneTreeDialog multiple times.
Seems the current workaround was deleting and recreating it.
See also this comment:

godot/editor/editor_interface.cpp

Lines 283 to 290 in 61accf0

	// TODO: Should reuse dialog instance instead of creating a fresh one, but need to rework set_valid_types first.
	if (node_selector) {
	node_selector->disconnect(SNAME("selected"), callable_mp(this, &EditorInterface::_node_selected).bind(p_callback));
	node_selector->disconnect(SNAME("canceled"), callable_mp(this, &EditorInterface::_node_selection_canceled).bind(p_callback));
	get_base_control()->remove_child(node_selector);
	node_selector->queue_free();
	}
	node_selector = memnew(SceneTreeDialog);

I took a stab at fixing this issue, clearing the filter's label and types before setting it.
Fixed the icons not showing up, but it calls _notification() directly to update the icon sizes. Would like some feedback on that too, seems unusual for the codebase.

[jasonmorgado]

After further testing I've found a bug where an error is thrown when alternating between adding Audio Tracks and Property tracks. (Between a type with and without a filter, needs to switch a few times).
I'll dig into it further, but if it doesn't work I can reuse the existing workaround of just re-creating the dialog box. Maybe write up an issue for the strange behavior around set_valid_types().

[jasonmorgado]

I've fixed the more consistent error message, but I occasionally get this one:
core/object/object.h:1036 - Condition "slot >= slot_max" is true. Returning: nullptr
So far I've only been able to replicate it quickly toggling between a Property and a Property with a filter, like Position 3D, opening the SceneTreeDialog, closing it with Esc, and opening a different one.

I guess if you don't spam open/close the Add Track dialog it should be fine. I'm not sure what causes this particular error message, so I could use some feedback if it would prevent the PR from being merged or can be ignored.

[AThousandShips]

Suggested change

	// Blend Shape is a property of MeshInstance3D
	valid_types.push_back(StringName("MeshInstance3D"));
	} break;
	case Animation::TYPE_POSITION_3D:
	case Animation::TYPE_ROTATION_3D:
	case Animation::TYPE_SCALE_3D: {
	// 3D Properties come from nodes inheriting Node3D
	valid_types.push_back(StringName("Node3D"));
	} break;
	case Animation::TYPE_AUDIO: {
	valid_types.push_back(StringName("AudioStreamPlayer"));
	valid_types.push_back(StringName("AudioStreamPlayer2D"));
	valid_types.push_back(StringName("AudioStreamPlayer3D"));
	} break;
	case Animation::TYPE_ANIMATION: {
	valid_types.push_back(StringName("AnimationPlayer"));
	// Blend Shape is a property of MeshInstance3D.
	valid_types.push_back(SNAME("MeshInstance3D"));
	} break;
	case Animation::TYPE_POSITION_3D:
	case Animation::TYPE_ROTATION_3D:
	case Animation::TYPE_SCALE_3D: {
	// 3D Properties come from nodes inheriting Node3D.
	valid_types.push_back(SNAME("Node3D"));
	} break;
	case Animation::TYPE_AUDIO: {
	valid_types.push_back(SNAME("AudioStreamPlayer"));
	valid_types.push_back(SNAME("AudioStreamPlayer2D"));
	valid_types.push_back(SNAME("AudioStreamPlayer3D"));
	} break;
	case Animation::TYPE_ANIMATION: {
	valid_types.push_back(SNAME("AnimationPlayer"));

[jasonmorgado]

I've committed the change here. Is there a particular reasoning behind using SNAME vs StringName? or even SceneStringName? Or plain string with just quotes?

[AThousandShips]

It is a dedicated macro creating a static instance, otherwise this creates a new StringName instance each time this method is run, forgot to add that to the comment when remaking it after some other changes

[Repiteo]

Thanks! Congratulations on your first contribution! 🎉