This gets ambient sounds (in particular, water and sky) working again
for quakeworld after the recent sound changes, and again for nq after I
don't know how long.
Care needs to be taken when freeing channels as doing so while an
asynchronous mixer is using them is unlikely to end well. However,
whether the mixer is asynchronous depends on the output driver. This
lets the driver inform the rest of the system that the output and mixer
are running asynchronously.
This improves the locality of reference when mixing and removes the
proxy sfx for streamed sounds.
The buffer for streamed sounds is allocated when the stream is opened
(since streamed sounds can't share buffers), and freed when the stream
is closed.
For block sounds, the buffer is reference counted (with the sfx holding
one reference, so currently block buffers never get freed), with their
reference count getting incremented on open and decremented on close.
That the reference counts get to 1 has been confirmed, so all that
should be needed is proper destruction of the sfx instances.
Still need to sort out just why channels leak across level changes.
Streams are the easy one as they were never in the cache. As a side
effect, sfxstream_t is much smaller as it no longer has the buffer
embedded in the struct.
More shrinkage. It turned out the mixer uses the phase fields, so they
couldn't be removed, but even at 192kHz, +/- 127 samples produces
sufficient phase separation for a 21cm head (which is, actually, pretty
big: mine is about 15cm across), but that change can come later.
The ambient sound loading has been removed from snd_channels because 1)
it doesn't work for nq, 2) it should never have been there in the first
place (it belongs in the client, but that needs some more API).
The scaling up of the volumes when setting a channel's volume bothered
me. The biggest issue being it hasn't been necessary for over a decade
since the conversion to a float-mixer. Now the volume and attenuation
scaling from protocol bytes is entirely in the client's hands.
sfx_t is now private, and cd_file no longer accesses channel_t's
internals. This is necessary for hiding the code needed to make mixing
and channel management *properly* lock-free (I've been getting away with
murder thanks to x86's strong memory model and just plain luck with
gcc).
The misinterpretations were due to either the cvar not being accessed
directly by the engine, but via only the callback, or the cvars were
accesssed only by progs (in which case, they should be float). The
remainder are a potential enum (hud gravity) and a "too hard basket"
(rcon password: need to figure out how I want to handle secret strings).
This is an extremely extensive patch as it hits every cvar, and every
usage of the cvars. Cvars no longer store the value they control,
instead, they use a cexpr value object to reference the value and
specify the value's type (currently, a null type is used for strings).
Non-string cvars are passed through cexpr, allowing expressions in the
cvars' settings. Also, cvars have returned to an enhanced version of the
original (id quake) registration scheme.
As a minor benefit, relevant code having direct access to the
cvar-controlled variables is probably a slight optimization as it
removed a pointer dereference, and the variables can be located for data
locality.
The static cvar descriptors are made private as an additional safety
layer, though there's nothing stopping external modification via
Cvar_FindVar (which is needed for adding listeners).
While not used yet (partly due to working out the design), cvars can
have a validation function.
Registering a cvar allows a primary listener (and its data) to be
specified: it will always be called first when the cvar is modified. The
combination of proper listeners and direct access to the controlled
variable greatly simplifies the more complex cvar interactions as much
less null checking is required, and there's no need for one cvar's
callback to call another's.
nq-x11 is known to work at least well enough for the demos. More testing
will come.
I had forgotten to test with shared libs and it turns out jack and alsa
were directly accessing symbols in the renderer (and in jack's case,
linking in a duplicate of the renderer).
Fixes#16.
on_update is for pull-model outpput targets to do periodic synchronous
checks (eg, checking that the connection to the actual output device is
still alive and reviving it if necessary)
Output plugins can use either a push model (synchronous) or a pull
model (asynchronous). The ALSA plugin now uses the pull model. This
paves the way for making jack output a simple output plugin rather than
the combined render/output plugin it currently is (for #16) as now
snd_dma works with both models.
This brings the alsa driver in line with the jack render (progress
towards #16), but breaks most of the other drivers (for now: one step at
a time). The idea is that once the pull model is working for at least
one other target, the jack renderer can become just another target like
it should have been in the first place (but I needed to get the pull
model working first, then forgot about it).
Correct state checking is not done yet, but testsound does produce what
seems to be fairly good sound when it starts up correctly (part of the
state checking (or lack thereof), I imagine).
Due to quake's original sound engine using a push model, the actual place
to which the sound data should be written is not necessarily where the
"hardware" dma cursor is, but rather where the last write finished off.
Thus, the correct output location is indicated by snd_paintedtime rather
than snd_shm->framepos.
the resampler is being badly abused for streams, and it's not yet properly
autoconfiscated, but things are working. Better yet, at the correct pitch and
speed.
