Improve Scene Tree editor performance

[hpvb]

We now cache the Node*<>TreeItem* mapping in the SceneTreeEditor. This allows us to make targeted updates to the Tree used to display the scene tree in the editor.

Previously on almost all changes to the scene tree the editor would rebuild the entire widget, causing a large number of deallocations an allocations. We now carefully manipulate the Tree widget in-situ saving a large number of these allocations.

There is definitely more that could be done, but this is already a massive improvement.

This fixes #83460

[hpvb]

Before: (this scene has about 15,000 nodes)

Screencast.From.2024-11-26.02-11-22.mp4

After:

Screencast.From.2024-11-26.02-10-35.mp4

[arkology]

Stealing @AThousandShips 's job 🤣

[arkology]

I confirm that birdies are in the nest (dots at the end of the comments)😃

[KoBeWi]

Changing valid types does not update the nodes (they stay disabled/enabled).

Can be tested with this simple EditorScript:

extends EditorScript
func _run() -> void:
	EditorInterface.popup_node_selector(func(n): print(n), ["Node2D"])

Run it, then remove "Node2D" and run again. Nodes that didn't match originally will stay disabled.

[KoBeWi]

The buttons don't get updated on various actions, including toggling unique name, making instance local, changing configuration warnings, adding node to group, connecting etc. The tooltip also doesn't update.
In case of making instance local, if you undo this operation, the nodes from the instance will incorrectly remain in the tree.

[hpvb]

@KoBeWi okay I changed the design entirely. The cache now uses a custom hashing function to keep track of changes, this should be easier to keep consistent. This is a smidge slower than the previous way of doing it but still way faster than what we had.

I have tested the following:

• Toggling unique names / undo
• Make local / undo
• Configuration warning / solve warning / undo
• Adding to group / undo / Adding to group while connected / undo
• Connecting a signal / undo/ Connecting signal while in a group / undo
• Editable children / undo
• Reparenting node / undo
• Reordering node / undo
• Change editor theme / and back
• popup_node_selector (your test case)

[KoBeWi]

• Make Local does not update icon. Also the node still has scene path in tooltip.

godot.windows.editor.dev.x86_64_HHOrYYEJ18.mp4

• Editable children lose color once you add a node.

godot.windows.editor.dev.x86_64_2lyvNQzXzb.mp4

• Attaching/removing the script does not update the icon (it was updating when I tested previously).

godot.windows.editor.dev.x86_64_5cxcUDaMEk.mp4

• Lock/Group icons don't update in scene tree when they are toggled.

• Same with AnimationPlayer's pin.
  

• Inherited scenes don't show their child nodes in yellow.

• Changing Node's process_mode to disabled does not make the sub-tree gray.

• When using Reparent... option, the reparented nodes in the dialog should appear red, but they don't.

[hpvb]

@KoBeWi I think I addressed your issues. Part of the reason I didn't figure it out was that there's a bug in master already whereby in the reparent node dialog nodes with disabled processing wouldn't show up as red. This is also fixed in this PR now.

The following things were tested:

old tests:

• Toggling unique names / undo
• Make local / undo
• Configuration warning / solve warning / undo
• Adding to group / undo / Adding to group while connected / undo
• Connecting a signal / undo/ Connecting signal while in a group / undo
• Editable children / undo
• Reparenting node / undo
• Reordering node / undo
• Change editor theme / and back
• popup_node_selector (your test case)

new tests:

• Reparenting node via dialog, verified the colors and behavior against master
• Creating connections via connections dialog, verified colors and behavior against master
• Adding a script / undo
• Make local / undo (verify icon/tooltip state)
• Create new node in an "editable children" scene, verify colors match master
• Toggle lock/unlock/undo, verify that lock icon appears in the scene tree
• Verify that AnimationPlayer pin matches behavior on master
• Set a node process mode / undo
• Toggle unique name / undo
• Reparent node via dialog, with the nodes having processing disabled. Verify that they still turn red (unlike on master)
• Reparent node, cancel out of dialog, reparent a differnt node, validate that nodes do not stay red

[KoBeWi]

Found another bug with node selector.
Changing type now properly changes colors, but the nodes stay unselectable.

[KoBeWi]

I checked the implementation and looks like the main idea is hashing everything relevant for node appearance and using it to update only when needed. This means that every time we add something new that can affect anything about TreeItems we need to add it to the hash; rather error-prone, but the improved performance makes this compromise reasonable.
Though there are still some properties tracked outside of the hash. I wonder if they could be included too.

There are still a couple of bugged cases, but other than that I think the PR is fine overall.

[hpvb]

I checked the implementation and looks like the main idea is hashing everything relevant for node appearance and using it to update only when needed. This means that every time we add something new that can affect anything about TreeItems we need to add it to the hash; rather error-prone, but the improved performance makes this compromise reasonable. Though there are still some properties tracked outside of the hash. I wonder if they could be included too.

As for changing the hash, I agree that it is a bit more work but on the other hand, for new things added it not showing up in the editor should be immediately apparent, unlike now where we are adding it now.

The things checked outside of the hash are things that are related to the editor state, not the node state. I didn't want to have to pass variables into the _hash_node() method. I could make it work that way if you'd like? It'd be pretty much the same amount of code.

For the pre_filter_color, that cannot be part of the hash as it is something that happens after nodes are updated and is also purely editor state.

There are still a couple of bugged cases, but other than that I think the PR is fine overall.

• Nodes stay unselectable in the filter screen after changing the node type
• Renaming a group doesn't get reflected on the tooltip

I think that is all you found this round, right?

[KoBeWi]

Yes, last time I just checked all code that sets custom color or adds buttons, but there are other ways how TreeItems can be changed. There might be some tooltip changes I missed.

The things checked outside of the hash are things that are related to the editor state, not the node state. I didn't want to have to pass variables into the _hash_node() method. I could make it work that way if you'd like?

If you need to pass more than TreeItem then it's not worth it.

[hpvb]

Yes, last time I just checked all code that sets custom color or adds buttons, but there are other ways how TreeItems can be changed. There might be some tooltip changes I missed.

The things checked outside of the hash are things that are related to the editor state, not the node state. I didn't want to have to pass variables into the _hash_node() method. I could make it work that way if you'd like?

I'll go through _update_tooltip with a fine-tooth comb to make sure I have indeed caught everything.

If you need to pass more than TreeItem then it's not worth it.

I would have to, yes. I'll leave it as-is then.

[hpvb]

@KoBeWi I think I addressed your concerns and fixed the remaining bugs. I've also made the hash function smaller by relying on signals to update some aspects of the editor. These signals get emitted by Node itself, they must also be emitted if a script changes them. This claws back quite a lot of performance compared to the original non-hash based version.

Please be aware that quite a bit changed compared to last time!

The following things were tested:

• Rename node / undo
• Toggling unique names / undo
• Make local / undo (verify icon/tooltip state)
• Configuration warning / solve warning / undo
• Adding to group / undo / Adding to group while connected / undo
• Connecting a signal / undo/ Connecting signal while in a group / undo
• Editable children / undo (verify color)
• Create new node in an "editable children" scene, verify colors match master
• Reparenting node / undo
• Reparenting node via dialog, verified the colors and behavior against master
• Reordering node / undo
• Change editor theme / and back
• popup_node_selector (your test case) Make sure that node selectability is updated appropriately
• Creating connections via connections dialog, verified colors and behavior against master
• Adding a script / undo
• Toggle lock/unlock/undo, verify that lock icon appears in the scene tree
• Verify that AnimationPlayer pin matches behavior on master
• Set a node process mode / undo
• Reparent node, cancel out of dialog, reparent a differnt node, validate that nodes do not stay red

new tests:

• Change editor description, verify that tooltip changes.
• Change group name group name does not change, this matches master behavior.
• Create CollisonShape outside of a Body, move it into the body, verify that warnings clear.
• Open connect dialog, close, add script to node, open, close, remove script from node, open,close verify that everything updates correctly.
• Change type of node with children, ensure that that all warnings update correctly upwards and downwards in the tree.

[hpvb]

I think I see a couple more ways to optimize things a bit further. I'll make more changes, sorry for the extra noise.