performance on iOS

[Johan Vos]

Hi,

I did some performance tests on Android and iOS. I am using
https://github.com/Ciruman/DemoFX.git which is forked from
https://github.com/chriswhocodes/DemoFX and made mobile-ready.

On my Nexus 5, I easily get 30 fps with triangles (the first test). On my
old iPad, this is only 3 fps. I've reports we achieve 5-6 fps on an iPad
Air.

Digging into the potential bottlenecks, I found out that the native
function responsible for 50% of the CPU time is glTexSubImage2D which seems
to be slow on iOS (e.g. see
http://stackoverflow.com/questions/21162688/gltexsubimage2d-slow-on-ios7)
but it is heavily used in prism-es2.

Any advice?

Thanks,

- Johan