Seems like we've got some nice polygon clipping now

We're using the Sutherland-Hodgeman algorithm now since it's quite fast (although not the fastest) and we don't need arbitrary polygons.

It would be indeed nice to use Stencil, and it's also possible to batch draw with Stencil....just Cocos2d-x doesn't support it nicely. I did quite some research before resorting to software clipping.
You'd have to create your own StencilManager that keeps an eye on all Stencil rendered skeletons and then batches at first the Stencil draw calls to the Stencil buffer and afterwards the normal draw calls. I think that this would be the best solution for Spine, but it might take some time to implement.
Since we don't need that clipped skeletons, we did sacrifice a bit of performance here for an easier implementation. But sacrificing batch rendering is just not an option ever, it's creating a mess in the whole drawing hierarchy and it just costs a lot of performance.

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LegioXV, not it's not supported in Starling and GM runtimes yet (the latter is maintained by YoYoGames who'd need to add this functionality.

famusrock, that's awesome! Batching is much easier to retain with software clipping than with stencil. The latter, as you identified, introduces a lot of complications, and making it work with arbitrary rendering graphs without breaking batching is extremely hard. I'll try to figure out the best clipping algorithm for our use case. Since we only clip triangles against arbitrary polygons, there may be some tricks we can apply.

I should also note that no matter how we implement clipping, it will always incur runtime overhead. Nobody should apply it to all their skeletons in their scene, we will not be able to make it work fast enough in that case.

Badlogic, are there any timeline for updating Starling-spine runtimes to support this?
I'm asking, because missing mask feature makes my life really hard for doing some animations (even right now). So it's not just curiosity.

badlogic, There was a thread in the cocos2d-x forums about stencil clipping being a problem and not being able to do easy batch rendering. I mentioned there that you guys are also struggling with it and improvements might be needed. Maybe nite from the cocos2d-x forums (or another cocos2d-x dev can help you guys with the stencil batching, or even fix it in cocos2d-x, so you'll have an easier live implementing it:

http://discuss.cocos2d-x.org/t/reduce-clippingrectanglenode-draw-calls/35143/7

@LegioXV it will take some time, as starling doesn't support clipping in hardware at all. We'll need a software solution for this, which is a bit tougher to implement.

@framusrock I'll follow up with the cocos2dx guys. The path of least resistance for all runtimes is definitely software clipping, and I favor that at the moment.

Any news on when the update will be live?

Any updates on when the new version will be live?

We are still working on it. Check out the waffle for progress and things that have been done. You can filter by the 3.6 milestone to see open issues for that release.

After updating to beta I find out some veird issue.
All slots in Animate tinted blue with transparent alpha
http://i.imgur.com/ZGXWqZB.jpg

In my situation all slots in Setup should be with "alpha 0". That's requirement from our developers.
In Animate in 0 frame for all needed slots manualy sets up "alpha 255".
So that's maybe the reason but it's strange anyway.

this is the problem .... i gave 1% weight to a particular set of mesh points and when i move the bone the mesh goes crazy and weird ....
similar thing happened with another mesh but it was totally opposite ..... even if i gave 100% weight the mesh points didn't move single pixel .....

3.6 Release Date? Soon or still months of development?

Real soon now.

Spine-Unity for Spine 3.6 beta 1 unitypackage is now up.
See the download page for more info! Spine Unity Download

This also includes the recent AnimationState changes mentioned in the blog. Blog: AnimationState: multiple mixing without dipping