I'm actually using cocos2d-iphone - the objective c framework.
I don't think it is Spine that is the problem, as such. Its something in my attempt to adapt the Spine runtime for Cocos2D-iphone from 2.x to 3.x - something really really tiny I'm sure.
Basically here:
https://github.com/sarah-j-smith/spine- ... ton.m#L182
....in the draw, the textureAtlas is not displaying textures.
I've cross-posted on the Cocos2D-iphone forums, but the answers I'm getting are basically "the spine guys are working on it" - tho' I'm not really sure that is right. I'm guessing you have a lot of other stuff planned before updating this runtime.
OK, after a day of searching and hacking it turned out to be an issue with the way Cocos2D v3 handles colours, with respect to the alpha calculation.
I have not done a proper fix for this - at present since my spine files don't use colour tinting at all - I've just set r, g, b, and a to 255 inside RegionAttachment_updateQuad(...) as here:
https://github.com/sarah-j-smith/spine- ... hone.m#L70
This makes my spine character display in my game, and I'm too tired right now to fix it properly.
If someone wants to take what I've done and add in a proper fix for the colour calculation then you've got a Cocos v3 compatible runtime.
You're welcome. :-)