This will make it easier to integrate into the enhanced branch, and
also improved audio quality slightly (samples are mixed as 16-bit
instead of 8-bit).
The mixer itself is integer-only, but the millibel stuff is still
float-based (I don't know if it's worth adding a 10001-value-long
lookup table to replace it).
Anyway, according to a quick test, this new mixer is significantly
faster than the old floating-point one - rarely going above 100
clock() ticks per callback, with the old one almost always running
above that.
For now, only the SDL2 backend supports it - I'll add the others in
upcoming commits.
This will no-doubt cause problems with the enhanced (lite) branch,
where clownaudio always outputs float samples.
This commit changes which variables are static: the Mac (and
presumably the Linux) debug data tells you what variables are static,
by prefixing their names with double_underscores.
The variable names themselves also hint at this: global variables are
prefixed with 'g', and use upper-camelcase, while static variables
use whatever_you_call_this.
After asking around, people really seem to prefer Xbox-style
controllers. Admittedly, when I was playtesting with Nintendo
controls, I wound up using my fingers to press A/B because of how
awkward it was.
Prevents a crash on the Wii U port in 1280x720 when you try to open
the pause menu. There's a giant delay now instead, and I'm not sure
where it comes from. Still, it's an improvement.
The Wii U has a very limited pool of memory for render targets
(32MB), so we should only use it if we have to.
This 'fixes' a bug in the enhanced branch, where if you use 2x
sprites at 854x480, the third line of the text box will be corrupted
(text will appear on the second line instead, and be black instead of
white).
The other renderers haven't been updated for the API change yet.
