d3cd26e922
Castlevania II, Jackal, and several other titles repeatedly drop the
triangle channel into a period range that produces only ultrasonic
output (raw period <= 3, > ~12 kHz at NTSC). The hardware itself
plays these tones, but the DAC reconstruction filter in HQ mode
folds the ultrasonic energy back into the audible range as popping.
The LQ tri/noise/PCM mixer (RDoTriangleNoisePCMLQ) already gates the
triangle channel with `freq[0] <= 4` (i.e. raw period <= 3) for
exactly this reason -- the popping has been absent in LQ since
forever. The HQ path (RDoTriangle) never had the equivalent gate,
so users on Sound Quality = High/Very High hear the popping that LQ
users do not.
Mirror the gate in RDoTriangle, controlled by a new core option
`fceumm_removetrianglenoise` (default disabled). When the option
is off the codegen is identical to before -- gcc folds the
`FSettings.RemoveTriangleNoise && (...)` check via short-circuit
evaluation, the per-sample inner loop is untouched. When on, HQ
behaves like LQ for the triangle ultrasonic case and the popping
disappears.
LQ is intentionally left untouched -- it has always silenced these
tones unconditionally and changing that would be an audible behavior
shift for existing LQ users. The new option is HQ-only.
Backport reference: negativeExponent's libretro-fceumm_next fork
(commit afaa8f5) added the same option, gating both LQ and HQ paths
on it. This patch is the more conservative subset: only adds the
HQ gate, leaves LQ at its current (always-silencing) behaviour.
Build / codegen verified:
- sound.c -O2 / -O3 clean, +15 lines in RDoTriangle (.text),
inner per-sample for-loop unchanged.
- libretro.c clean (options_list[] widened from [25] to [32] to
fit the new key name).
- aarch64 cross-build clean.
FCE Ultra mappers modified
FCEU "mappers modified" is an unofficial build of FCEU Ultra by CaH4e3, which supports a lot of new mappers including some obscure mappers such as one for unlicensed NES ROM's.
Sequential targets Light Guns support added
Support for Sequential targets Light Guns has been added. "Gun Aux A" serves as light sensor logic input.