似乎您在代码中使用了 AtlasUtilities Skin.GetRepackedSkin() 创建新的Atlas纹理。
It seems that you are using AtlasUtilities Skin.GetRepackedSkin() in your code to create new atlas textures.

如果我正确理解了您的问题，那么您只需要像您的主要纹理一样重新包装口罩图集即可。 这可以通过Skin.GetRepackedSkin() 处的附加参数 additionalTexturePropertyIDsToCopy 和additionalOutputTextures来实现，请参阅文档此处。
If I understand your question correctly, then you only need to repack the mask atlas like your main texture. This can be achieved by the additional parameters additionalTexturePropertyIDsToCopy and additionalOutputTextures at Skin.GetRepackedSkin(), see documentation here.

然后，您将在additionalOutputTextures处传递参数new int[] { Shader.PropertyToID("_SfxMaskTex") } ，以创建蒙版纹理的打包图集。
You would then pass the parameter new int[] { Shader.PropertyToID("_SfxMaskTex") } at additionalOutputTextures to also create a packed atlas of your mask textures.

您是否考虑过使用Spine 3.8重新导出所有骨架资产？ 有一个命令行界面可用于通过脚本导出所有资产：
Export - Spine User Guide: Command line
例如，这是一个脚本，用于导出所有Spine示例项目并创建纹理地图集：
spine-runtimes/export.sh at 3.8

Have you considered re-exporting all skeleton assets with Spine 3.8? There is a command line interface available to export all assets via script:
Export - Spine User Guide: Command line
For example, here is a script we use to export all the Spine example projects and to create texture atlases:
spine-runtimes/export.sh at 3.8

如果这不是一个选择，我建议您在3.6 spine-unity运行时（AtlasUtilities.cs）中应用此提交所做的更改：
https://github.com/EsotericSoftware/spine-runtimes/commit/fc0a5df0db99916286047ab2577da7332be47bb4
更改可以手动应用，因为它们不会太多。
至少这比编写着色器映射逻辑要容易。

If this is not an option, I would rather suggest you to apply this commit's changes in your 3.6 spine-unity runtime (AtlasUtilities.cs):
https://github.com/EsotericSoftware/spine-runtimes/commit/fc0a5df0db99916286047ab2577da7332be47bb4
The changes could be applied manually, as they are not too many.
At least this should be easier than writing the shader mapping logic.