diff options
Diffstat (limited to 'sound/mixer.cpp')
-rw-r--r-- | sound/mixer.cpp | 44 |
1 files changed, 43 insertions, 1 deletions
diff --git a/sound/mixer.cpp b/sound/mixer.cpp index 93ea0c0f09..eae370e12b 100644 --- a/sound/mixer.cpp +++ b/sound/mixer.cpp @@ -179,6 +179,9 @@ MixerImpl::~MixerImpl() { void MixerImpl::setReady(bool ready) { _mixerReady = ready; + + // If the mixer is set to ready, then we better have a positive sample rate! + assert(!_mixerReady || _sampleRate > 0); } uint MixerImpl::getOutputRate() const { @@ -241,6 +244,44 @@ void MixerImpl::playInputStream( } } + // Check if the mixer is not ready. This most probably means that + // no Audio output is possible according to the backend (we should + // clarify this in the Mixer creation API, though). + // + // For now we deal with this by simply ignore the sound here, never + // scheduling it for playback, never giving it a valid sound + // handle. For a game engine, this is indistinguishable from a + // sound which finishes playback before playInputStream returns. + // + // This is certainly not ideal for many engine; e.g. if a game has + // scripts which sync by waiting for certain sounds to play, then + // this syncing is broken if we just remove the sound. + // + // We could try to be more graceful, by using TimerManager and + // emulating (or rather: faking) actual audio playback; essentially + // we run the mixer callback from a timer instead of an audio + // callback. + // However, this may very well lead to new problems of its own, + // plus it would complicate the Mixer code. It seems that a better + // solution would be to adapt backends to setup a fake mixer thread + // which calls the mixer callback. We'd then still need a way to + // signal the mixer / the client code that no actual audio playback + // takes places... Anyway, either way, we first would have to + // investigate ramifications of any such approach. + // + // And also, by far the best solution is to adapt engines to be + // properly aware of the possibility of missing audio, and how to + // deal with it; be it by refusing to launch (e.g. when audio is an + // integral part of a game), by switching to alternate script + // syncing means, etc. It also seems important to test every game + // individually in a system without audio, if we really want + // to support such systems. + if (!_mixerReady) { + if (autofreeStream == DisposeAfterUse::YES) + delete input; + return; + } + // Create the channel Channel *chan = new Channel(this, type, input, autofreeStream, reverseStereo, id, permanent); chan->setVolume(volume); @@ -258,6 +299,7 @@ void MixerImpl::mixCallback(byte *samples, uint len) { // Since the mixer callback has been called, the mixer must be ready... _mixerReady = true; + assert(_sampleRate > 0); // zero the buf memset(buf, 0, 2 * len * sizeof(int16)); @@ -334,7 +376,7 @@ Timestamp MixerImpl::getElapsedTime(SoundHandle handle) { const int index = handle._val % NUM_CHANNELS; if (!_channels[index] || _channels[index]->getHandle()._val != handle._val) - return Timestamp(0, _sampleRate); + return Timestamp(0, _sampleRate ? _sampleRate : 1); return _channels[index]->getElapsedTime(); } |