The two fudge factors in the reverb path cancelled, which is why the
overall level felt roughly right.
- The send is accumulator * 0x20 >> 16, i.e. sample >> 2. We used >> 1,
driving the reverb 6dB hot.
- The return is (evol * out) >> 11. We used >> 12, i.e. 6dB quiet.
Net level is therefore unchanged, but the reverb now runs at the level
the presets were designed around. That matters because the filter clamps
internally, so a 6dB hot input changes how the feedback path saturates -
worst on the presets with heavy feedback.
Also adds a slider in the imgui.
The reverb presets came from nocash's PS1 table. Six of the nine are
identical on the PSP, but three are not.
Also correct our linear interpolation expression: we were close but
our formula can produce an off by 1 at times.
sceSasSetGrain took no validation at all, unlike sceSasInit's grain
size check - a bad value could both throw on SasInstance::SetGrainSize's
allocation and, for a moderately large but successfully-allocated
value beyond PSP_SAS_MAX_GRAIN, read out of bounds of the fixed-size
mixTemp_ buffer during mixing. Apply the same bounds sceSasInit uses.
SasReverb::SetPreset() only checked the upper bound of `preset` before
indexing presets[], not the lower bound (-1 means "off"). The only
live HLE entry point (sceSasRevType) already clamps to [-1, 8], but
DoState() passes a savestate-deserialized value straight through with
no revalidation, so a corrupted/malicious savestate could index
presets[] negatively.
Previously, it sounded horrible in Sol Trigger - can be observed in
tutorial boxes when going into battle, for example, and also several other
effects. Halving this value sounds a lot more correct.
It's not clear what value exactly is correct.
Added a bit of code that only enables it when a reverbed sound is active. This will need to be turned off later but useful right now for hearing when it's used..
Henrik Rydgård