Method OutputDeviceNode

src/cinder/audio/OutputNode.cpp:83–112

// ----------------------------------------------------------------------------------------------------

OutputDeviceNode::OutputDeviceNode( const DeviceRef &device, const Format &format )
	: OutputNode( format ), mDevice( device )
{
	if( ! mDevice ) {
		string errorMsg = "Empty DeviceRef.";
		if( ! audio::Device::getDefaultOutput() )
			errorMsg += " Also, no default output Device so perhaps there is no available hardware output.";

		throw AudioDeviceExc( errorMsg );
	}

	// listen to the notifications sent by device property changes in order to update the audio graph.
	mWillChangeConn = mDevice->getSignalParamsWillChange().connect( bind( &OutputDeviceNode::deviceParamsWillChange, this ) );
	mDidChangeConn = mDevice->getSignalParamsDidChange().connect( bind( &OutputDeviceNode::deviceParamsDidChange, this ) );

	mInterruptionBeganConn = Context::deviceManager()->getSignalInterruptionBegan().connect( [this] { disable(); } );
	mInterruptionEndedConn = Context::deviceManager()->getSignalInterruptionEnded().connect( [this] { enable(); } );

	size_t deviceNumChannels = mDevice->getNumOutputChannels();

	// If number of channels hasn't been specified, default to 2 (or 1 if that is all that is available).
	if( getChannelMode() != ChannelMode::SPECIFIED ) {
		setChannelMode( ChannelMode::SPECIFIED );
		setNumChannels( std::min( deviceNumChannels, (size_t)2 ) );
	}

	// Double check the device has enough channels to support what was requested, which may not be the case if the user asked for more than what is available.
	if( deviceNumChannels < getNumChannels() )
		throw AudioFormatExc( string( "Device can not accommodate " ) + to_string( deviceNumChannels ) + " output channels." );
}

void OutputDeviceNode::deviceParamsWillChange()
{