/*
* Copyright (C) 2010, Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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*/
#ifndef ScriptProcessorNode_h
#define ScriptProcessorNode_h
#include "platform/audio/AudioBus.h"
#include "modules/webaudio/AudioNode.h"
#include "wtf/Forward.h"
#include "wtf/PassRefPtr.h"
#include "wtf/RefPtr.h"
#include "wtf/Vector.h"
namespace WebCore {
class AudioBuffer;
class AudioContext;
class AudioProcessingEvent;
// ScriptProcessorNode is an AudioNode which allows for arbitrary synthesis or processing directly using JavaScript.
// The API allows for a variable number of inputs and outputs, although it must have at least one input or output.
// This basic implementation supports no more than one input and output.
// The "onaudioprocess" attribute is an event listener which will get called periodically with an AudioProcessingEvent which has
// AudioBuffers for each input and output.
class ScriptProcessorNode FINAL : public AudioNode {
public:
// bufferSize must be one of the following values: 256, 512, 1024, 2048, 4096, 8192, 16384.
// This value controls how frequently the onaudioprocess event handler is called and how many sample-frames need to be processed each call.
// Lower numbers for bufferSize will result in a lower (better) latency. Higher numbers will be necessary to avoid audio breakup and glitches.
// The value chosen must carefully balance between latency and audio quality.
static PassRefPtr<ScriptProcessorNode> create(AudioContext*, float sampleRate, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
virtual ~ScriptProcessorNode();
// AudioNode
virtual void process(size_t framesToProcess) OVERRIDE;
virtual void initialize() OVERRIDE;
virtual void uninitialize() OVERRIDE;
size_t bufferSize() const { return m_bufferSize; }
DEFINE_ATTRIBUTE_EVENT_LISTENER(audioprocess);
private:
virtual double tailTime() const OVERRIDE;
virtual double latencyTime() const OVERRIDE;
ScriptProcessorNode(AudioContext*, float sampleRate, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
static void fireProcessEventDispatch(void* userData);
void fireProcessEvent();
// Double buffering
unsigned doubleBufferIndex() const { return m_doubleBufferIndex; }
void swapBuffers() { m_doubleBufferIndex = 1 - m_doubleBufferIndex; }
unsigned m_doubleBufferIndex;
unsigned m_doubleBufferIndexForEvent;
Vector<RefPtr<AudioBuffer> > m_inputBuffers;
Vector<RefPtr<AudioBuffer> > m_outputBuffers;
size_t m_bufferSize;
unsigned m_bufferReadWriteIndex;
unsigned m_numberOfInputChannels;
unsigned m_numberOfOutputChannels;
RefPtr<AudioBus> m_internalInputBus;
// Synchronize process() with fireProcessEvent().
mutable Mutex m_processEventLock;
};
} // namespace WebCore
#endif // ScriptProcessorNode_h