Alpha blending issues on some platforms

[[Unknown]]

Well, a few things:

1. Just a note about Mali-400. With most drivers, I'm pretty sure many of the shaders we generate (depends on game) are too complex, causing it to use the CPU for lighting and transforms rather than the GPU (it turns off the hardware transform setting.) This only occurs in some areas of some games, but if/when it does it will get poor performance. So Mali vs PowerVR depends on where you're testing.

2. As long as you use buffered rendering (which should be, "allow games to use buffers during rendering"), games at least shouldn't be using the backbuffer's depth/stencil/alpha. So if games don't look fine, there's something else going on. If games do look fine, then yeah, probably there is some issue with alpha indeed.

3. PowerVR is not very fast when you discard pixels, which has to be done when using the outdated technique of alpha testing. Unfortunately, pretty much every PSP game ever made uses alpha testing, and many use it very heavily. We aggressively try to optimize it out, which helps a lot afaik, but it still gives a big penalty to PowerVR. There's a speedhack in settings to disable alphatesting entirely, it will definitely cause glitches in most games though.

Is Qt able to build on any of these platforms? Might be interesting if that works. Does libretro use something other than SDL? What does it use?

-[Unknown]