low-pass into the zone WAVs
232 zones author initialFilterFc(8)/initialFilterQ(9) (SBK 0..127) -- the
fixed resonant low-pass the EMU8000 applied in hardware; the port played
them unfiltered (flagship: the LaserLoaded charge hum, fc=57 Q=87, much
brighter/harsher than the arcade). The extractor now applies an RBJ 2-pole
low-pass per zone: cutoff = the AWE NRPN curve (100 + fc*7900/127 Hz),
resonance = SBK Q -> 0..+12 dB peak [T3 curve, endpoints exact], designed at
the zone's baked rate so note-60 playback reproduces the hardware's absolute
cutoff (pitch-shifted notes carry the filter -- same limitation as the
rate-baked tuning). Synthetic sweep verified: flat lows, +5.4 dB at the
authored 3.6 kHz cutoff, -22 dB @10 kHz, -46 dB @14 kHz.
Whole bake pipeline (filter -> attenuation) now runs in float with ONE int16
conversion + peak normalization: an int-per-stage draft hard-clipped 165 of
232 zones (resonance overshoot, worst 3% of samples); now only pre-existing
source-material clipping remains (14 files). 160 WAVs re-baked; the preset
table is unchanged (no engine rebuild).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Root cause of "no sound, ever": the two audio backend DLLs shipped in the repo
are fakes. libsndfile-1.dll exports 15 funcs BY ORDINAL ONLY (no names) and
sf_open() always returns NULL; OpenAL32.dll (72KB) imports only KERNEL32 -- no
dsound/wasapi/winmm -- so it is a pure no-op that returns fake handles
(ctx=0x00000001, alGenSources->0) and never touches the hardware. The whole
render->device->buffer->source->play chain ran clean and silent.
Fixes:
- OpenAL32.dll: replace the stub with the real OpenAL Soft 1.25.2 Win32 build
(imports AVRT/ole32/WINMM, real WASAPI backend). The exe imports the 25 AL
funcs by NAME so it is a drop-in; alGenSources now yields a live source and
alSourcePlay reaches AL_PLAYING.
- libsndfile: DROPPED entirely. It is replaced by LoadWavPCM() in L4AUDRES --
a tiny RIFF/WAVE fmt+data reader that loads our soundbank WAVs (16-bit PCM)
straight into the AL buffer. Removed the .lib/.dll from the link + copy and
git-rm'd the stub. (This also kills the "ordinal 50 could not be located in
libsndfile-1.dll" load-failure popup: adding an sf_strerror import bound to
an ordinal the 2..16-only stub could not satisfy.)
- Soundbank: 241 samples cracked from AUDIO1/2.RES (SF2 v1.0) by
tools/sf2extract.py into content/AUDIO/*.wav + the allPresets[2][128] table
(audiopresets.cpp), replacing the zero-init btstubs stub. All 241 now load
(alErr=0). BT_AUDIO_TEST plays buffer0 as proof-of-life; BT_AUDIO_LOG traces
the chain.
Remaining: in-game triggering (AudioEntities on fire/step/engine/explosion)
so PlayNote fires during play -- next audio wave.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Clean, self-contained extraction of the BattleTech-specific work from the
reverse-engineering workspace -- engine + game + content + build, with nothing
from Red Planet or the raw archive dumps. Builds green (Win32) and runs the
single-player drive->animate->target->fire->damage->destroy loop out of the box.
Layout:
engine/ MUNGA + MUNGA_L4 shared 2007 engine, carrying our BT render/loader
work (bgfload/L4D3D/L4VIDEO: BSL bit-slice decode, LOD/ground/shadow
models) + image codec; the minimal rp/ headers the audio HAL needs
game/ reconstructed BT logic + surviving-original BT source + fwd shims
+ WinMain launcher
content/ full runtime tree (BTL4.RES, VIDEO/, GAUGE/, AUDIO/, eggs, BTDPL.INI)
docs/ format specs + reconstruction ledgers
reference/ raw Ghidra pseudocode (recon source-of-truth) + decomp exporter
tools/ MP console emulator + map/resource scanners
One top-level CMake builds munga_engine lib + bt410_l4 game lib + btl4.exe.
All paths relativized (186 fwd shims + ~437 CMake abs paths -> repo-relative);
DXSDK is the one external, overridable via -DDXSDK. Verified: builds to a
byte-identical 2.27MB exe and runs combat (TARGET DESTROYED, 0 crashes) against
the bundled content.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
