Alpha blending issues on some platforms

[memeka]

Hi,

Thanks for the reply. I have tried the alpha testing setting, I know that PVR is slow in that.
The alpha blending issue appears not just in the games, but also in the PPSSPPSDL menu (the background of the +, X, O floating around)...
I did not try Qt, but I think that under X11 things also look fine.
So it must be a difference in framebuffer drivers - e.g. Mali400 and Mali450 use v similar drivers, but there is a difference between the samsung fb driver in Odroid-U3 (where there is no alpha issue) and the amlogic driver for the C1.

Libretro has a graphic context driver for framebuffer - which is the one I basically ported to SDL2. So SDL2 initialises EGL the same way as retroarch does. Hence my suspicion that there must be some settings from when the screen is set up, and not the emulation code itself.

I am not sure if this matters, but the retroarch context driver does not support shared context, so the libretro version only works with buffered rendering. in PPSSPPSDL non-buffered also works - well, with black instead of alpha, of course.

I hope what I am writing here makes sense, it's pretty late in the night