/*
* Copyright (C) 2010, Google Inc. All rights reserved.
*
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#ifndef AudioDestinationNode_h
#define AudioDestinationNode_h
#include "platform/audio/AudioBus.h"
#include "platform/audio/AudioIOCallback.h"
#include "platform/audio/AudioSourceProvider.h"
#include "modules/webaudio/AudioBuffer.h"
#include "modules/webaudio/AudioNode.h"
namespace WebCore {
class AudioBus;
class AudioContext;
class AudioDestinationNode : public AudioNode, public AudioIOCallback {
public:
AudioDestinationNode(AudioContext*, float sampleRate);
virtual ~AudioDestinationNode();
// AudioNode
virtual void process(size_t) OVERRIDE FINAL { } // we're pulled by hardware so this is never called
// The audio hardware calls render() to get the next render quantum of audio into destinationBus.
// It will optionally give us local/live audio input in sourceBus (if it's not 0).
virtual void render(AudioBus* sourceBus, AudioBus* destinationBus, size_t numberOfFrames) OVERRIDE FINAL;
size_t currentSampleFrame() const { return m_currentSampleFrame; }
double currentTime() const { return currentSampleFrame() / static_cast<double>(sampleRate()); }
virtual unsigned long maxChannelCount() const { return 0; }
virtual void startRendering() = 0;
protected:
// LocalAudioInputProvider allows us to expose an AudioSourceProvider for local/live audio input.
// If there is local/live audio input, we call set() with the audio input data every render quantum.
class LocalAudioInputProvider FINAL : public AudioSourceProvider {
public:
LocalAudioInputProvider()
: m_sourceBus(AudioBus::create(2, AudioNode::ProcessingSizeInFrames)) // FIXME: handle non-stereo local input.
{
}
void set(AudioBus* bus)
{
if (bus)
m_sourceBus->copyFrom(*bus);
}
// AudioSourceProvider.
virtual void provideInput(AudioBus* destinationBus, size_t numberOfFrames) OVERRIDE
{
bool isGood = destinationBus && destinationBus->length() == numberOfFrames && m_sourceBus->length() == numberOfFrames;
ASSERT(isGood);
if (isGood)
destinationBus->copyFrom(*m_sourceBus);
}
private:
RefPtr<AudioBus> m_sourceBus;
};
virtual double tailTime() const OVERRIDE FINAL { return 0; }
virtual double latencyTime() const OVERRIDE FINAL { return 0; }
// Counts the number of sample-frames processed by the destination.
size_t m_currentSampleFrame;
LocalAudioInputProvider m_localAudioInputProvider;
};
} // namespace WebCore
#endif // AudioDestinationNode_h