Trying to find differences in Lighthouse's audio sample playback,
I discovered that SCI3 had its own variant of handling volumes and
sending this volume information back to game scripts. It is not
known if this fixes any sound bug.
This update should give the game the default mix it receives in
Windows. If necessary, the half-volume audio bug in the DOS
interpreter can be added as an additional hack for this game, since
there are still some sub-par audio mixes that might need additional
correction (like Curtis talking to Blob when taking her out of the
cage in his apartment at the start of the game) which were also
bad in the Windows version of the game.
Fixes Trac#10165.
This was happening in games with game scripts that control the
master volume themselves by applying the master volume to each
channel sent to the kernel, instead of relying on the kernel to
manage the master volume for them.
This can occur when a save game from the past is loaded and the
audio system was paused prior to loading the save game. This was
fixed eventually in SSCI somewhere around GK2, since it pauses
all audio before restoring a game and then resumes it after the
save game is loaded (after all of the audio channels have been
added from the save game). Since this would seem to be a problem
for earlier games as well, this change is applied universally
instead of being conditionally applied only to the games with
interpreters containing this change.
This patch contains some additional sanity checks that emit
warnings if individual channels end up being started from the
future. There was never such checking in SSCI, and it does not
seem likely to ever happen, but it is unclear right now if this is
an actual problem or not.
Since Resource::makeStream returns a MemoryReadStream which will
not attempt to free the resource memory, it is fine to always
dispose those streams and get rid of the separate resourceStream
property, which was a holdover from some past WIP resource design
which no longer exists.
Upon investigation of Sound code across SCI32 games, it was
determined that there are actually (at least) 3 different
revisions, not just a single SCI2.1 version. This patch only
changes the parts of Sound code that are relevant to the correct
use of Audio32.
Fixes Trac#9736, Trac#9756, Trac#9767, Trac#9791.
The previous code for attenuating audio channels was not accurate,
so samples were quieter than they were supposed to be when mixed
together. Robots were also being mixed without attenuation, which
was incorrect.
1. Unlocking all resources of a type using a resource ID of -1 is
gone in SCI32;
2. Audio locks need to be serialized starting in GK2 for the game's
modified kDoAudio(1) call;
3. Audio locks in SCI3 must work more like SSCI, since at least
Lighthouse's `BackMusic::fade` method will attempt to unlock
audio that was never locked by a script. In SSCI (and now in
ScummVM too) this is a no-op; previously in ScummVM, it would
remove Audio32's own lock on the audio resource, resulting in a
use-after-free;
4. kDoAudio(1) starting in GK2 returns the number of active
*not-in-memory* channels being played, not the total number of
active channels.
Fixes Trac#9675.
SCI3 changes the way that monitored channel works. In SCI2/2.1,
when a channel is monitored, it is the only audible channel. In
SCI3, monitored channels mix normally.
This is very noticeable in LSL7, where music disappears totally
during speech if the monitored channel is the only channel played
back.
This patch includes enhancements to the ScummVM integration with
SCI engine, with particular focus on SCI32 support.
1. Fixes audio volumes syncing erroneously to ScummVM in games
that modify the audio volume without user action (e.g. SCI1.1
talkies that reduce music volume during speech playback). Now,
volumes will only be synchronised when the user interacts with
the game's audio settings. This mechanism works by looking for
a known volume control object in the stack, and only syncing
when the control object is present. (Ports and planes were
researched and found unreliable.)
2. Fixes audio syncing in SCI32 games that do not set game
volumes through kDoSoundMasterVolume/kDoAudioVolume, like GK1,
GK2, Phant1, and Torin.
3. Fixes speech/subtitles syncing in SCI32 games that do not use
global 90, like LSL6hires.
4. Fixes in-game volume controls in SCI32 games reflecting
outdated audio volumes when a change is made during the game
from the ScummVM launcher.
5. Fixes SCI32 games that would restore volumes from save games
or reset volumes on startup, which caused game volumes to be
out-of-sync with ScummVM when started.
6. ScummVM integration code for audio sync has been abstracted
into a new GuestAdditions class. This keeps the ScummVM-
specific code all in one place, with only small hooks into the
engine code. ScummVM integrated save/load code should probably
also go here in the future.
Fixes Trac#9700.
Several functions in Audio32 would call into the mixer to pause
or resume the audio handle, which would cause a deadlock if the
mixer's mixCallback timer fired while one of these functions was
running on the main thread.
To address this, calls to mixer to pause/unpause the digital audio
handle have been removed. Since this was just an optimisation to
prevent unnecessary calls to fill the audio buffer, the only
problem now is that a tiny amount of CPU is wasted on unnecessary
callbacks to read from the empty SCI mixer.
Using the one from SCI2.1mid makes fades very slow because SDL has
a larger audio buffer than SSCI DOS. This new algorithm is based on
wall time so will always fade at the correct speed, although the
larger buffers will have a coarser granularity so the fades may
not be as smooth as in the original engine. If anyone cares, the
fade volume could be mixed into individual samples in `readBuffer`
instead of applying just once per complete buffer. SSCI did not
do this, however, so this implementation should be pretty accurate.
This provides a complete implementation of kDoAudio through
SCI2.1mid, plus partial implementation of SCI3 features.
Digital audio calls shunted through kDoSound have also been
updated to go through the SCI32 audio mixer, though these shunts
are a bit hacky because the ScummVM implementation of kDoSound
does not currently match how SSCI kDoSound is designed.
It is probably possible in the future to just replace the SCI1.1
audio code (audio.cpp) with the new SCI32 code, since the major
differences seem to be that (1) SCI1.1 only supported one digital
audio playback channel (this is configurable already), (2) it
had extra commands for CD audio playback and queued sample
playback.
Cameron Cawley
sluicebox
Eugene Sandulenko
Orgad Shaneh
Filippos Karapetis
Bastien Bouclet
Colin Snover