This fades the dry mixing gains using a logarithmic curve, which should produce
a smoother transition than a linear one. It functions similarly to a linear
fade except that
step = (target - current) / numsteps;
...
gain += step;
becomes
step = powf(target / current, 1.0f / numsteps);
...
gain *= step;
where 'target' and 'current' are clamped to a lower bound that is greater than
0 (which makes no sense on a logarithmic scale).
Consequently, the non-HRTF direct mixers do not do not feed into the click
removal and pending click buffers, as this per-sample fading would do an
adequate job of stopping clicks and pops caused by extreme gain changes. These
buffers should be removed shortly.
This reverts commit 25b9c3d0c15e959d544f5d0ac7ea507ea5f6d69f.
Conflicts:
Alc/mixer_neon.c
Unfortunately this also undoes the Neon-enhanced ApplyCoeffsStep method.
Unlike the device, input buffers are accessed based on channel numbers
instead of enums. This means the maximum number of channels they hold
depends on the number of channels any one format can have, rather than
the total number of recognized channels. Currently, this is 8 for 7.1.
This update allows for much more flexibility in the HRTF data. It also allows
for HRTF table file names to include "%r" to represent the device's playback
rate (e.g. if you set hrtf-%r.mhr, then it will try to use hrtf-44100.mhr or
hrtf-48000.mhr depending if the device's output rate is 44100 or 48000,
respectively).
The makehrtf utility has also been updated to support more options and input
file formats, as well as the new mhr format.
