public AudioVoice(AudioEngine engine, SoundEffectInstance effectInstance, WaveFormat desiredFormat)
{
if (engine == null) throw new ArgumentNullException("engine");
if (desiredFormat == null) throw new ArgumentNullException("desiredFormat");
audioEngine = engine;
soundEffectInstance = effectInstance;
waveFormat = desiredFormat;
BusIndexMixer = uint.MaxValue;
if (desiredFormat.BitsPerSample != 16)
throw new AudioSystemInternalException("Invalid Audio Format. " + desiredFormat.BitsPerSample + " bits by sample is not supported.");
lock (StaticMembersLock)
{
if (nbOfInstances == 0)
{
// Create the Audio Graph
audioGraph = new AUGraph();
// Open the graph (does not initialize it yet)
audioGraph.Open();
// Create the AudioComponentDescrition corresponding to the IO Remote output and MultiChannelMixer
var remoteInOutComponentDesc = AudioComponentDescription.CreateOutput(AudioTypeOutput.Remote);
var mixerMultiChannelComponentDesc = AudioComponentDescription.CreateMixer(AudioTypeMixer.MultiChannel);
var mixer3DComponentDesc = AudioComponentDescription.CreateMixer(AudioTypeMixer.Spacial);
// Add the Audio Unit nodes to the AudioGraph
var outputUnitNodeId = audioGraph.AddNode(remoteInOutComponentDesc);
var idChannelMixerNode = audioGraph.AddNode(mixerMultiChannelComponentDesc);
var id3DMixerNode = audioGraph.AddNode(mixer3DComponentDesc);
// Connect the nodes together
CheckGraphError(audioGraph.ConnnectNodeInput(idChannelMixerNode, 0, outputUnitNodeId, 0), "Connection of the graph node failed.");
CheckGraphError(audioGraph.ConnnectNodeInput(id3DMixerNode, 0, idChannelMixerNode, MaxNumberOfTracks), "Connection of the graph node failed.");
// Get the MixerUnit objects
unitChannelMixer = audioGraph.GetNodeInfo(idChannelMixerNode);
unit3DMixer = audioGraph.GetNodeInfo(id3DMixerNode);
// Set the mixers' output formats (the stream format is propagated along the linked input during the graph initialization)
var desiredSampleRate = (engine.AudioSampleRate != 0) ? engine.AudioSampleRate : AudioUnitOutputSampleRate;
unit3DMixer.SetAudioFormat(CreateLinear16BitsPcm(2, desiredSampleRate), AudioUnitScopeType.Output);
unitChannelMixer.SetAudioFormat(CreateLinear16BitsPcm(2, desiredSampleRate), AudioUnitScopeType.Output);
// set the element count to the max number of possible tracks before initializing the audio graph
CheckUnitStatus(unitChannelMixer.SetElementCount(AudioUnitScopeType.Input, MaxNumberOfTracks+1), string.Format("Failed to set element count on ChannelMixer [{0}]", MaxNumberOfTracks+1)); // +1 for the 3DMixer output
CheckUnitStatus(unit3DMixer.SetElementCount(AudioUnitScopeType.Input, MaxNumberOfTracks), string.Format("Failed to set element count on 3DMixer [{0}]", MaxNumberOfTracks));
// set a null renderer callback to the channel and 3d mixer input bus
for (uint i = 0; i < MaxNumberOfTracks; i++)
{
CheckUnitStatus((AudioUnitStatus)SetInputRenderCallbackToNull(unit3DMixer.Handle, i), "Failed to set the render callback");
CheckUnitStatus((AudioUnitStatus)SetInputRenderCallbackToNull(unitChannelMixer.Handle, i), "Failed to set the render callback");
}
// Initialize the graph (validation of the topology)
CheckGraphError(audioGraph.Initialize(), "The audio graph initialization failed.");
// Start audio rendering
CheckGraphError(audioGraph.Start(), "Audio Graph could not start.");
// disable all the input bus at the beginning
for (uint i = 0; i < MaxNumberOfTracks; i++)
{
CheckUnitStatus(unitChannelMixer.SetParameter(AudioUnitParameterType.MultiChannelMixerEnable, 0f, AudioUnitScopeType.Input, i), "Failed to enable/disable the ChannelMixerInput.");
CheckUnitStatus(unit3DMixer.SetParameter((AudioUnitParameterType)_3DMixerParametersIds.Enable, 0f, AudioUnitScopeType.Input, i), "Failed to enable/disable the 3DMixerInput.");
}
// At initialization all UnitElement are available.
availableMixerBusIndices = new Queue<uint>();
for (uint i = 0; i < MaxNumberOfTracks; i++)
availableMixerBusIndices.Enqueue(i);
}
++nbOfInstances;
// Create a AudioDataRendererInfo for the sounds.
pAudioDataRendererInfo = (AudioDataRendererInfo*)Utilities.AllocateClearedMemory(sizeof(AudioDataRendererInfo));
pAudioDataRendererInfo->HandleChannelMixer = unitChannelMixer.Handle;
pAudioDataRendererInfo->Handle3DMixer = unit3DMixer.Handle;
}
}
