o Added SoundMixer::isReady()

o Removed SoundMixer::bindToSystem()
o In scumm, replaced _silentMixer, _silentDigitalImuse and _noDigitalSamples by SoundMixer::isReady()

svn-id: r11893

3 files changed, 20 insertions, 21 deletions

diff --git a/sound/audiostream.cpp b/sound/audiostream.cpp
index 8ac57481ee..f3bf3552f9 100644
--- a/sound/audiostream.cpp
+++ b/sound/audiostream.cpp
@@ -218,7 +218,7 @@ void WrappedMemoryStream<stereo, is16Bit, isUnsigned>::append(const byte *data,
 	else if (is16Bit || stereo)
 		assert((len & 1) == 0);
 	
-	// Verify the stream has not been finalized (by a call to finish()) yet
+	// Verify that the stream has not yet been finalized (by a call to finish())
 	assert(!_finalized);
 
 	if (_end + len > _bufferEnd) {
diff --git a/sound/mixer.cpp b/sound/mixer.cpp
index 1d0e13a0c1..1549424720 100644
--- a/sound/mixer.cpp
+++ b/sound/mixer.cpp
@@ -101,22 +101,27 @@ public:
 
 
 SoundMixer::SoundMixer() {
-	_syst = 0;
-	_mutex = 0;
+	_syst = OSystem::instance();
+	_mutex = _syst->create_mutex();
 
 	_premixParam = 0;
 	_premixProc = 0;
 	int i = 0;
 
-	_outputRate = 0;
+	_outputRate = (uint) _syst->property(OSystem::PROP_GET_SAMPLE_RATE, 0);
+
+	if (_outputRate == 0)
+		error("OSystem returned invalid sample rate");
 
 	_globalVolume = 0;
 	_musicVolume = 0;
 
 	_paused = false;
-
+	
 	for (i = 0; i != NUM_CHANNELS; i++)
 		_channels[i] = 0;
+
+	_mixerReady = _syst->set_sound_proc(mixCallback, this, OSystem::SOUND_16BIT);
 }
 
 SoundMixer::~SoundMixer() {
@@ -127,17 +132,6 @@ SoundMixer::~SoundMixer() {
 	_syst->delete_mutex(_mutex);
 }
 
-bool SoundMixer::bindToSystem(OSystem *syst) {
-	_syst = syst;
-	_mutex = _syst->create_mutex();
-	_outputRate = (uint) syst->property(OSystem::PROP_GET_SAMPLE_RATE, 0);
-
-	if (_outputRate == 0)
-		error("OSystem returned invalid sample rate");
-
-	return syst->set_sound_proc(mixCallback, this, OSystem::SOUND_16BIT);
-}
-
 void SoundMixer::setupPremix(PremixProc *proc, void *param) {
 	Common::StackLock lock(_mutex);
 	_premixParam = param;
diff --git a/sound/mixer.h b/sound/mixer.h
index d1bd379408..9001245e0e 100644
--- a/sound/mixer.h
+++ b/sound/mixer.h
@@ -82,17 +82,22 @@ private:
 	int _musicVolume;
 
 	bool _paused;
-
+	
 	Channel *_channels[NUM_CHANNELS];
 
+	bool _mixerReady;
+
 public:
 	SoundMixer();
 	~SoundMixer();
 
-	/** bind to the OSystem object => mixer will be
-	 * invoked automatically when samples need
-	 * to be generated */
-	bool bindToSystem(OSystem *syst);
+	/**
+	 * Is the mixer ready and setup? This may not be the case on systems which
+	 * don't support digital sound output. In that case, the mixer proc may
+	 * never be called. That in turn can cause breakage in games which use the
+	 * premix callback for syncing. In particular, the Adlib MIDI emulation...
+	 */
+	bool isReady() const { return _mixerReady; };
 
 	/**
 	 * Set the premix procedure. This is mainly used for the adlib music, but