Each resampler allocates an input buffer and an output buffer.
Since we create ~100 audio stream objects (1 per `sfx_MISC` effect),
the memory cost of these buffers adds up.
Avoids creating a resampler when the audio sampler rate matches the
output sample rate. This is mostly the case when the output sample
rate is 22050.
When using `UNPACKED_MPQS`, avoid all the SDL machinery for reading
files.
This is beneficial not only due to reduced indirection but also because
we can test for the file's existence and get the file size without
opening it, which is much faster.
libmpq is a much simpler alternative to StormLib for reading MPQ archives.
We use our own fork of libmpq: https://github.com/diasurgical/libmpq
Impact:
* DevilutionX is now a lot more portable. Unlike StormLib, libmpq only
needs platform-specific code for Windows.
* Locks around file access **removed** (instead we duplicate the file descriptor for streamed audio only).
* RAM usage is **300 KiB** lower than StormLib.
* Stripped release linux_x86_64 binary is **32 KiB** smaller.
* Amiga build now hangs instead of crashing.
When playing the same sound twice with in a short duration then the
sound it self, the secound request would go unfulfilled. The solution is
to simply rewind the stream pointer before requesting a playback.
SDL_mixer can only stream a single music track
SDL_audiolib has unlimited streams.
With this change, we finally have streaming sounds (respecting
sfx_STREAM).
Audio options can now also be set via diablo.ini, which should help us
better diagnose the static noise issues.
obligaron