NijiNeko Sorry for the late reply. The spine-pixi runtime does not provide a parameter to manually set whether a texture is PMA or not, but I think it would be better if you could tell us exactly what you are having trouble with. In spine-pixi, PMA textures are used even in the examples, and I think you should use PMA textures unless there is a very special reason not to. Is there a specific reason why you need to use straight alpha textures? And have you encountered any problems when actually using it?

NijiNeko If the original Spine projects have not been lost, a few hundred projects is not that many. Using the export shell script that we made available, you can re-export all Spine projects within a specific folder. Unless re-exporting is truly difficult, I recommend repacking the textures in PMA.

Davide, who is responsible for the spine-pixi runtime, will be away for a while, so he may be able to advise you when he returns, but for now, I think it would be best to look for an easier way to repack the textures.

NijiNeko

Which runtime, runtime version, and Spine assets version are you using?
Could you share a comparison screenshot or video showing the actual result versus the expected one?
If possible, sharing the assets here or via email could help us provide more targeted assistance.

As Spinebot already mentioned, in PixiJS the only texture parameters you can control are the min/mag filters and mipmap generation. These values are typically read from the .atlas file, but you can also override them manually by accessing the Pixi texture directly.
As a last resort, you might consider modifying the shader, though that would be a more advanced approach.

NijiNeko

Until I can see a comparison between the actual and expected results, and have access to one of your assets, my ability to help will remain limited.

In spine-pixi-v8, straight alpha / PMA is automatically read from the atlas file—there’s no need to set it manually.
You can adjust the min/mag filters by editing the filter values in your .atlas file. See here for how Spine filter values map to Pixi's.
If you prefer not to modify the atlas file, you can override those values directly on the Pixi textures, as mentioned earlier.

I don't quite understand how to control the shader, I lack knowledge in this area.

Shaders aren’t simple toggle settings, they’re actual GPU-side programs you have to write. Modifying them requires a good understanding of graphics programming and could impact your game’s performance, since a custom shader must be used to render Spine skeletons.

NijiNeko

Sure! You can send your assets at contact@esotericsoftware.com