Add Sorting Group functionality for CanvasItem sorting

[xmxy-wt]

Describe the project you are working on

I am working on a sample project where each unit is assembled from various body parts, and different z-indexes are set for each body part to achieve a simple layering effect.

Describe the problem or limitation you are having in your project

However, when two units overlap on the map, a very bad phenomenon occurs.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

The "Sorting Group" feature allows a parent node to treat all child nodes as a single sorting layer during sorting. This is crucial for animated characters composed of multiple body parts, as relying solely on Z_index for sorting when characters overlap can lead to poor results. For more details on this specific feature, please refer to this link: https://docs.unity.cn/2019.4/Documentation/Manual/class-SortingGroup.html.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

one unit

two units overlapping

The correct effect

If this enhancement will not be used often, can it be worked around with a few lines of script?

You can control the layering of nodes using code to achieve the layering effect, eliminating the need for z-index. However, if the unit is composed of four directions, it will be very troublesome to modify the unit direction without using z-index, and the workload will increase several times.

Is there a reason why this should be core and not an add-on in the asset library?

I believe this is a essential feature for a game engine.

[AThousandShips]

Have you tried using canvas layers? And y-sorting?

[xmxy-wt]

Have you tried using canvas layers? And y-sorting?

Using "canvas layers" as the parent node allows for a layered display effect. However, the position of "canvas layers" cannot be modified; only the positions of its child nodes can be changed. This makes it very difficult to control characters, and the performance during testing is very poor.

[xmxy-wt]

您是否尝试过使用画布图层？还有 y 排序？

Using Y-ordering would completely eliminate the use of Z-index. In complex skeletal animation, it is difficult to give up on Z-index.

[AThousandShips]

Have you tried using relative z-indices? And putting each character on a z-index themselves?

[xmxy-wt]

您是否尝试过使用相对 z 指数？并把每个字符放在 z 索引上？ If Z_index is set, Godot completely overrides the Y sorting and layer limitations, causing all characters under the same canvas to follow Z_index sorting. This would be very bad. ![Uploading part_intersect.png…]()

[AThousandShips]

You didn't upload the image

[xmxy-wt]

You didn't upload the image

Sorry, it seems there is a problem with the network. Can you please check the second image where I asked the question?

I'm really sorry. I'm worried that my use of translation software may result in unclear language expression and cause inconvenience for you.

[AThousandShips]

You can upload it again, you have to wait until it says done :)

[Calinou]

You may want to look into the CanvasGroup node as well.

[dalexeev]

Related:

• https://github.com/godotengine/godot-proposals/issues/6080#issuecomment-1381625999
• RenderingServer.canvas_item_set_draw_index()

• 3971

• 6337

[AdriaandeJongh]

Just to double check: if the parent of the unit / character in the original post's example has y-sorting enabled, but the unit root itself has it disabled, shouldn't that group the unit at its patent y-position regardless of the unit's subsequent structure?

[xmxy-wt]

In order to implement features like Ysort group, I spent a lot of work on animation. And the final product's performance fell short of expectations. I find it hard to imagine such a mature GODOT engine without such a feature.

Just to double check: if the parent of the unit / character in the original post's example has y-sorting enabled, but the unit root itself has it disabled, shouldn't that group the unit at its patent y-position regardless of the unit's subsequent structure?