.fat sound banks¶

A sound bank packs RIFF/WAVE files into one file. resource.hog holds most of them; CD1.HOG and CD2.HOG each add VRSFX.FAT and VRSND.FAT, and a copy of wlksmp.fat identical to resource.hog's.

sltool fat ls <bank>                  # every sound: offset, size, priority, format, length
sltool fat extract <bank> <out-dir>   # every sound as a WAV file
make sounds                           # every sound in resource.hog into game/sounds

Layout¶

The sounds follow the entries back to back, to the end of the file, and each is a complete WAVE file (formats/wave.zig) whose RIFF length matches its entry's size. All but one are IMA ADPCM (format 0x11, 4 bits per sample, with a fact chunk giving the length) at 11,025, 22,050 or 44,100 Hz, mono or stereo; the other is 16-bit PCM. sltool fat extract writes them unchanged.

Playback¶

The engine reads a whole bank into memory with its generic file loader, hog_read_file (0x004C7F60), and plays sound n of it with sound_play (0x00481F80), which passes Miles the WAVE file at bank + offset. The priority decides whether a sound may take over a voice already playing: the player finds the busy voice of lowest priority and stops it only for a sound whose priority is higher, then records the new sound's priority on the voice (Sound).

The shipped banks use priorities 1, 5, 50 and 10000. Most hold a single sound: those named for the flyable fighters, such as PREDATOR.FAT, each hold one at priority 10000. betty.fat holds the cockpit warnings.

The payload loads stdsmp.fat, ldsmp.fat, smp3d.fat, betty.fat, newsloop.fat, waitloop.fat, wlksmp.fat, vrsfx.fat, vrsnd.fat and inter\itac\itacsnd.fat by name.