[AD] Android & Blending Bug

[Trent Gamblin <trent@xxxxxxxxxx>]

I have come across an issue on Android which is very common but it's a
bug with the OpenGL implementation on some devices. Many Androids don't
support glBlendFuncSeparate, even though they claim to be OpenGL ES 2.0
compliant -- in practice this leads to solid black pixels in place of
alpha in sprites. It can't be ignored as there are a lot of very popular
phones that exhibit the problem. I've heard from at least 5 people who
had the problem out of maybe 20 or 25. So to fix it, I simply use the ES
1.0 path in ogl_draw.c. I don't know about anyone else but I rarely ever
have used separate blending and never in a finished game. Not sure what
to do though -- change Allegro or just leave it. Opinions?