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