The volume keys wanted a partner, and the bass trim could not be one as it
stood: it scaled the sample data as it loaded, so by the time anyone pressed
a key the audio was already sitting in OpenAL buffers and nothing short of a
restart would move it.
So the trim is now a per-zone gain applied in the mix instead. Each buffer's
depth - how much of the low band it occupies - is still worked out once at
load from its playback rate, but the trim itself is read every frame, which
is what lets Home and End move it while sounds are playing. It is the better
form regardless: no rewriting of sample data, and no quantisation on top of
audio that has already been through one gain stage.
Home raises, End lowers, in steps of 0.05, and the setting is written to
bass.cfg beside the exe exactly as the volume writes volume.cfg. Together
with PageUp and PageDown that is the amplifier and the crossover the
cabinets had in hardware and a desktop does not.
Builds clean, runs, and neither knob fires unprompted.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The cabinets ran the game at unity and shaped volume and tone outside it,
in an external amplifier and a 3-way crossover. That is why there is no
master volume anywhere in the original code and none in AUDIO.INI - an
operator turned a knob on an amp. A desktop player has no amp and no
crossover, and the recovered soundbanks are a good deal livelier than what
4.12 shipped with, so the game has to offer the two controls the pod got
from hardware.
RP412AUDIOVOLUME, 0.0 to 4.0, is the amplifier: a listener gain, which the
port had never set at all. RP412AUDIOBASS, 0.0 to 1.0, is the crossover's
low band. Both default to leaving the mix exactly as the pod played it, so
neither changes anything for anyone who does not go looking.
The bass trim is not a filter, and the reason is worth writing down: the
OpenAL we ship is Creative's, not OpenAL Soft, and it implements only
AL_FILTER_LOWPASS. It rejects highpass and bandpass outright. A bandpass
would have been the tidy answer, carrying the authored brightness model on
GAINHF and the trim on GAINLF across the single direct filter a source
gets. It is not on offer.
So the trim scales sample data as it loads, which suits how this low end is
actually built: the weight lives in discrete deep layer zones whose per-zone
tuning bakes out to a very low playback rate - thirteen zones below 8kHz,
three to five octaves under their recorded pitch, against four fifths of the
set at 22kHz and up. Baked rate is a dependable proxy for band, so pulling
down the low-rate zones is a real low-band trim and not a blunt cut. It eases
in below 22kHz and reaches full depth at 5.5kHz.
Caught while building this, and the reason for the probe: EFX_Initialize
checks alGetError after configuring the scratch filter, so asking for a
filter type the driver refuses leaves an error pending and takes the entire
bridge down - reverb included. The bandpass attempt did precisely that and
would have silently killed the reverb and brightness work. Initialize now
survives losing the filter and says so.
Builds clean, runs with both knobs set and with neither.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Recovering the soundbanks took voice demand per sound from about one zone to
about two and a half, and the audio path allocated an OpenAL source for every
sound event and destroyed it again on release. Sources are a hard
per-context resource - this driver grants 256 - so that churn doubled at
exactly the moment it got more expensive. Sources are now generated once and
recycled through a free list: measured, three sources generated across
twelve thousand acquisitions.
The BT tree reached the same conclusion the expensive way, from field logs
full of failed acquisitions: raising the source budget is not the fix,
because the ceiling also acts as a governor and more voices mixing is real
CPU during exactly the busiest moments. Recycling is the fix, and it costs
nothing.
Two older bugs were sitting underneath, both reproduced against the driver
rather than assumed:
Releasing a set leaked it. alDeleteSources is atomic - one bad name in the
array and nothing at all is deleted. ReleaseSourceSet handed it the whole
fixed-size array and then parked the slots at -1, so any partial set, and
any double release, leaked every source it held. Sources are now handed back
one at a time and slots park at 0, which is never a valid name.
A source set began life uninitialised. The constructor set only the count,
and the acquire path decided whether a slot was already filled by asking
OpenAL about uninitialised stack garbage. Garbage that happened to match a
live name meant two sounds silently sharing one source. Pooling would have
made that more likely, not less, since it keeps small names in circulation.
Recycled sources are scrubbed before parking - stopped, buffer detached,
looping, gain, pitch, relative flag, position and velocity reset, and the
EFX filter and reverb send dropped. Without that last part a dry cockpit
sound inherits the wet send of whatever 3D source held the name before it.
Verified: a deliberately dirtied source comes back clean.
Builds clean. Runs with memory and handle count flat.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The OpenAL port kept the whole authored audio model and then threw most of
its output away. Every frame the engine computed a distance-attenuation
curve, a high-frequency rolloff, doppler cents, a reverb level and a
front/rear placement, and every one of those consumers had been commented
out when the two AWE32 cards were replaced. What reached the speakers was
OpenAL's own defaults instead: a straight-line fade to silence, no
filtering, doppler at the wrong constants with an inverted velocity, no
reverb, and every cockpit sound dead centre.
Restored, per AUDIO.INI, which is byte-identical to the file that shipped
in August 1995:
- the authored knee/rolloff distance curve, replacing AL_LINEAR_DISTANCE.
This also un-blinds the transient cull, the voice-steal weighting and
the mix ducking, which all key off it and were treating far sources as
full presence
- the CC7 squared volume law; writing the scale linearly ran everything
about 6 dB hot at mid-scale
- brightness and distance muffling, and the wet-exterior/dry-cockpit
reverb split, both through a new OpenAL EFX bridge
- doppler on the moving-source path only, as the original had it
- front/rear placement from the authored position enum
The larger find is that AL_PITCH was never called anywhere in the tree, so
the entire pitch chain was inert - not only doppler but pitch_mix_offset,
which our own sequences author 97 times. Doppler alone would have changed
nothing audible.
Note pitch is applied for parity with the BT engine but is identity here:
our content predates NoteAudioControlID, so every source runs at note 60.
Builds clean on VS2022 Release|Win32. Smoke-tested against vRIO on COM1 -
reaches gameplay and holds a steady frame loop. ALC_EXT_EFX is present on
the build machine with all nine entry points, so the filter and reverb work
is live rather than inert. Not yet listened to on the pod, which is the
real test: the volume law changes the level of everything.
docs/SOUND.md documents the original two-card quadraphonic design, where
the surviving original assets are, and what remains.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Imports the current Win32 source for the pod-racing game 'Red Planet',
built on the MUNGA engine and its L4 (Win32/DirectX) platform layer:
- MUNGA / MUNGA_L4: cross-platform engine core and Win32 backend
- RP / RP_L4: Red Planet game logic and Win32 application
- DivLoader, Setup1: asset loader and installer project
- lib, MUNGA_L4/openal, MUNGA_L4/sos: third-party audio dependencies
Removed stale Subversion metadata and added .gitignore/.gitattributes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
CydandClaude Opus 5