WebGl is based on OpelGL ES 2.0. Is it correct to say that Stage3d is also based OpenGL? I mean does it call OpenGL functions? Or ot calles Direct3D when runs on Windows?
If no, could you explain me, what API does Stage3d use for hardware acceleration?
Good day, Stage3D isn't based on anything, it may share similar methodology/terminology. It is another rendering pipeline, this is why Adobe is soo pumped about it.
Have a look at this: http://www.adobe.com/devnet/flashplayer/articles/how-stage3d-works.html You can skip down to this heading "Comparing the advantages and restrictions of working with Stage3D" to get right down to it.
Also, take a peak at this: http://www.adobe.com/devnet/flashplayer/stage3d.html, excerpt:
The Stage3D APIs in Flash Player and Adobe AIR offer a fully hardware-accelerated architecture that brings stunning visuals across desktop browsers and iOS and Android apps enabling advanced 2D and 3D capabilities. This set of low-level GPU-accelerated APIs provide developers with the flexibility to leverage GPU hardware acceleration for significant performance gains in video game development, whether you’re using cutting-edge 3D game engines or the intuitive, lightning fast Starling 2D framework that powers Angry Birds.