its simple and a little stupid ...but work :p
methodA
1.draw a SkeletonAnimation to a renderTexture
2.draw the renderTexture with black_dilate_shader(you can apply antialias or blur on it)
3.draw SkeletonAnimation on the top of step2 result
methodB (LayersToPNG help a lot in methodB ~ thanks π )
1.draw each component with black_dilate_shader(i do a little edge blur the same time)
2.draw SkeletonAnimation on the top of step1 result
ps. you don't need set every component draw with glprogram just set once.
because update skeleton on renderTexture hit fps, but two skeletonAnimation don't,
so i choose methodB
its shock to me silhouette method use in 3d(draw a bigger one at back) don't make expect result.