Sound¶

How the game plays its sounds through the Miles Sound System (MSS32.DLL): the banks' sounds on voices of their own, the effects placed in 3D around the camera, and the music. OpenReliant's code is game/hog_snd.zig and game/sound3d.zig; what stands in for Miles is in Sound in OpenReliant. The banks are .fat files.

Start-up¶

WinMain calls sound_init (0x00481440) with 10 voices. It starts Miles, opens a digital driver at 22,050 Hz in 16-bit stereo, or at 11,025 Hz where that fails (sound_driver_open, 0x00482D10), allocates a sample for each voice, and starts the 100 Hz timer, tick_timer (0x004827C0). Asked for them, it also opens the CD's audio and sets aside two more samples and a double buffer for the radio's speech. sound_3d_providers (0x004817E0) lists Miles's 3D providers and sound_3d_open (0x00481900) opens the one the settings name, else the first of Miles Fast 2D Positional Audio, Aureal A3D Interactive (TM), Creative Labs EAX (TM) and RAD Game Tools RSX 3D Audio, with Dolby Surround for one of them where asked. It allocates a 3D voice for each sample the provider supports, up to 64, and sets the effects up on them (sound3d_init). That sets the provider's room to EAX's generic one (AIL_set_3D_room_type, 0), with a damping of 1 and an effect volume and decay time of 0, and each 3D sound it plays gets an effects level of 0, with no obstruction or occlusion: the room's reverb is never heard.

As the game's window is put away (window_suspended, 0x005DDD28, which 0x004A8260 sets and input_init clears) while the renderer runs (app_active, 0x005D6CAC), the message pump (message_pump, 0x004AAB20) pauses the music, the 3D voices and the voices, where no video is playing, and waits on the window's messages; once the window is back, it resumes the sound. app_inactive_paused (0x005D6CAD) remembers that it paused. Only in a multiplayer session with a mission loaded does it pause the mission too (game_pause), which then stays in its pause menu. In single player the mission is not paused, and the timer's ticks go on while the pump waits. Unverified: that the mission runs the ticks it missed once the window is active again.

Volumes¶

Four settings, each from 0 to 127, in [Sound] of starlancer.ini, which the options screen resets to their defaults:

sound_volumes_apply (0x00482990) sets them again on the music and every voice playing when one changes.

The banks' sounds¶

A voice of sound_voices (0x00565080) is 0x20 bytes:

sound_play (0x00481F80) plays sound n of a bank at a volume, a loop count, a pan and a pitch. It takes the first voice past voice 0 that has finished; else the first that was stopped; else the voice of lowest priority not held by the display, which it ends, if that priority is below the new sound's. sound_play_on_voice (0x004820C0) plays on a given voice. sound_start (0x004826A0) hands Miles the WAVE file at the entry's offset in the bank, at its own rate times 2^(n/24) for a pitch of n quarter tones (0x00481400, clamped to 96 each way), and at the volume round(((Fxvolume × volume) / 128) × Mastervolume / 127).

Improvement: OpenReliant divides by 127 where the game multiplies by a rounded reciprocal, for the master volume's share (0x004DC6B0) and the engine's volume (0x004DC9C8), and divides a 3D sound's length by the bytes a tick plays where the game multiplies by their reciprocal (0x004DC8B8).

Every five ticks tick_timer steps the fades: a fading voice loses its step of volume and ends at nothing. sound_voice_fade (0x004824C0) and sound_fade_all (0x00482510) start them; sound_pause_all (0x004825D0) and sound_resume_all (0x00482630) stop the playing voices and start them again.

The timer is a multimedia timer of its own (timer_start, 0x004A70F0), so the fades continue while a movie plays: the menu music, which starts fading out when a campaign starts, is gone half a second into the new pilot's intro. OpenReliant runs the timer once a frame from each of its loops, including the movie loop (hog_snd.Sound.runTimer).

Positional sounds of a frame¶

sound_buffer_at (0x00482160) gathers a sound of the first 18 slots at a place in the world: its level in each ear from its distance and which side of the camera it lies. Once a frame sound_buffers_play (0x004822F0) plays each slot gathered as sound n of bank_stdsmp, panned by its two levels and as loud as the louder, then clears them.

3D sounds¶

Each effect is a definition of the table at 0x00507140, 0x44 bytes each, closed by a record whose entry is -1; make sound-tables derives sound3d/sounds.zig from it.

What a sound follows sets its place as it starts and each frame after:

A 3D voice is 0x44 bytes at 0x00563F60: Miles's 3D sample at 0x00, what it follows at 0x04, its owner at 0x08 (-1 while free), the priority at 0x10, the maximum distance at 0x14, the point and direction at 0x18 and 0x24, whether it was borrowed at 0x34, the sound at 0x38, the frame it started at 0x3C, and the sound decompressed to PCM at 0x40.

Voice classes¶

Each 3D voice has a class (0x0058CB1C), from one of three rows at 0x005085B4 by how many voices the provider has: up to 14, up to 30, or more. The names are the executable's own (0x00508614):

A sound of classes 5 and 6 plays on the one voice of its class. Any other takes a voice of its own class that is free or borrowed, else such a voice of class 0, else borrows a free voice of any class but 4, 5 and 6.

Playing¶

sound3d_play (0x0049D360) takes a place and a direction, an owner, the sound, a volume and a class; a further argument goes unread. It places the sound by what it follows, relative to the camera and scaled by 0.0004 into Miles's units, its velocity by 1e-5 into a millisecond's. A sound beyond its maximum distance is not started, but for the engines' (PSHIP01 to PSHIP12) and BURNER01. It decompresses the bank's ADPCM into PCM (AIL_decompress_ADPCM), since Miles's 3D samples play PCM only, and plays it at the volume Mastervolume / 127 × Fxvolume × share × volume, with the definition's loop count, cone and distances, at 22,050 Hz; the two explosions at 18050 + 7000 × rand() / 32767. Miles's y points up where the camera's points down, so every place, direction and velocity goes over with y negated.

Fix: a sound that follows a shot, a missile or an object is placed by the owner's record, which the game reads for an owner of -1 too, before the table. OpenReliant plays nothing without an owner, or with one past its table.

Once a frame sound_3d_update (0x00481BF0) runs the engine's sound, then each voice playing. A voice past its sound's length, length / 441 ticks of 16-bit sound at 22,050 Hz, is freed but for the engine's and the afterburner's. A shot's and a missile's stay where they started; the rest are placed again by what they follow, and freed once beyond their maximum distance or once their object has gone. Nothing gives an object its voice (+0xB96 stays 0xFFFF), so missile_end, which ends a missile's, never does.

Improvement: a missile's voice follows it as an object's does, and is its own, so it ends with it; it keeps its full volume half as far again (sound3d.MissileSound.follows).

The player's engine¶

sound3d_engine_sound (0x0049DCB0) picks the engine's sound for the player's ship type: PSHIP01 on, by type; types from 244 count again from 0. A mission starts it as the ship launches (launch_reliant_run). sound3d_engine_update (0x0049DCF0) keeps it going through three states (0x0058CB04):

• Idle: the engine's rate and volume by the ship type's row of the tables at 0x00508740, 0x00508774, 0x005087A8 and 0x005087DC, at no throttle plus the throttle's share of what full throttle adds.
• Burning, while the afterburner or reverse thrust is on: BURNER01 on the afterburner's voice, its volume growing from 5 by 0.8 a tick to 70, and its rate 12000 + 90 × that, or 7000 in reverse.
• Cooling, once let go: the afterburner's sound fades over 25 ticks while the engine's plays on.

In view 13 neither is heard.

Ships flying past¶

The same update hears each fighter flying past the camera: within 10,000 units, not disabled, hidden or exploding, at a throttle of 0.4 or more and moving at 100 or more, its velocity at least a right angle from where the camera looks, or for a hostile one at least 41 degrees. A hostile ship sounds PASS01, another PASS02, on a voice of class 7, no more than once in 500 ticks, or 200 for the player's own, which is not heard in views 0 to 3, 12 and 15. The frame it was heard is kept at +0x67C.

Music¶

music_play (0x00482A80) plays a file as a Miles stream at a level and a loop count, at once where its now is 1 (0x00482A9D), or for any other value once the music playing has faded out (hog_snd.Sound.When.of). The mission script's PlayMusic (cmd_PlayMusic) plays music\ and the name it is given, for ever, at level 80, its second argument the now. A piece the table at 0x005017A0 names loops back to its own point, a byte offset into its data, once it has played through; the rest from the start. The stream's volume is round(((Musicvolume × level) / 127) × Mastervolume / 127). music_play fades the music playing out with music_fade_out (0x00482960), which takes the step it is given, 5 here, off the level every five ticks from the tick it starts on, until the stream closes, and music_update (0x00482C30) then starts the piece waiting. WinMain fades the music out by 15 before the hangar's movie of a mission it flies (Movies). Mission 1 plays new_launch.wav as its wing launches, and new_searching mission 09.wav once it is out. The CD player in the rooms plays the pieces of its lists, and turns their level (The CD player).

Speech¶

sound_init allocates a sample for the radio's speech (speech_sample, 0x00563F18) with two buffers (0x00563F20), which cbox.cpp streams a line through: speech_start (0x00461EB0) sets the sample up as 16-bit stereo at 22,050 Hz, both channels the same, at round(Speechvolume × Mastervolume / 127), which sound_volumes_apply sets again, and a timer decodes the line into the buffers as it plays (Speech files). OpenReliant decodes a line whole as it starts and plays it on the sample (cbox.zig), which then goes through OpenAL Soft's resampling and the master bus like every sound (Sound).

Improvement: the recordings push past full scale in a few samples of every thousand, which the game cuts flat, and crackle; OpenReliant rounds the peaks off, unchanged within 0.8 of full scale and eased toward it past that by a hyperbolic tangent (cbox.softClip). Improvement: the lines ring in the cockpit's cabin, as Betty's warnings do, where the game plays them dry. --original cuts the peaks and plays the lines dry.

The crew in the rooms speak their lines on voice 2, an MP3 file each, which Miles's MP3 decoder (MP3DEC.ASI) plays (The crew). OpenReliant reads the frames (MP3 files), and FFmpeg's MP3 decoder decodes them.

Where the sounds come from¶

• A shot the step hears (guns.heard) plays its gun type's sound following it, on a voice of the player's guns for the player's shots, of the guaranteed ones for the Huge Guns'.
• A flak shell plays FLAK01 as it bursts.
• The player's ship warns, sound 1 of betty.fat, once a quadrant has lost its shield and half its armour (Objects).
• A Huge Gun's shot striking a component plays EXPLOSION01 where it strikes.
• A shot through to a hull plays ARMOUR01 where it struck, facing the camera, or PLAYERHIT on the player's ship, following it, at most every 30 ticks (shieldfx_create, 0x004A0310). The game plays ARMOUR01 at the point in the part's own frame, taken for one in the world. Improvement: OpenReliant plays it where the shot struck.
• A shield generator whose part node_draw finds destroyed plays SHLDDOWN at the part, facing its way, and its object loses flag 0x4000.
• Turning the missile ring plays MISSILESELECT at the player's ship (hud_target_keys).

The display's own sounds are in The display's sounds.

Not ported: the CD's audio.