108 lines
4.6 KiB
C++
108 lines
4.6 KiB
C++
/*
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* Copyright (C) 2010, Google Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include "ActiveDOMObject.h"
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#include "AudioBus.h"
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#include "AudioNode.h"
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#include "EventListener.h"
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#include "EventTarget.h"
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#include <wtf/Forward.h>
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#include <wtf/RefPtr.h>
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#include <wtf/Vector.h>
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namespace WebCore {
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class AudioBuffer;
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class AudioContext;
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class AudioProcessingEvent;
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// ScriptProcessorNode is an AudioNode which allows for arbitrary synthesis or processing directly using JavaScript.
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// The API allows for a variable number of inputs and outputs, although it must have at least one input or output.
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// This basic implementation supports no more than one input and output.
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// The "onaudioprocess" attribute is an event listener which will get called periodically with an AudioProcessingEvent which has
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// AudioBuffers for each input and output.
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class ScriptProcessorNode final : public AudioNode, public ActiveDOMObject {
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WTF_MAKE_ISO_ALLOCATED(ScriptProcessorNode);
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public:
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// bufferSize must be one of the following values: 256, 512, 1024, 2048, 4096, 8192, 16384.
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// This value controls how frequently the onaudioprocess event handler is called and how many sample-frames need to be processed each call.
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// Lower numbers for bufferSize will result in a lower (better) latency. Higher numbers will be necessary to avoid audio breakup and glitches.
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// The value chosen must carefully balance between latency and audio quality.
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static Ref<ScriptProcessorNode> create(BaseAudioContext&, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
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virtual ~ScriptProcessorNode();
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const char* activeDOMObjectName() const override { return "ScriptProcessorNode"; }
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// AudioNode
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void process(size_t framesToProcess) override;
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void initialize() override;
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void uninitialize() override;
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size_t bufferSize() const { return m_bufferSize; }
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ExceptionOr<void> setChannelCount(unsigned) final;
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ExceptionOr<void> setChannelCountMode(ChannelCountMode) final;
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private:
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double tailTime() const override;
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double latencyTime() const override;
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bool requiresTailProcessing() const final;
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ScriptProcessorNode(BaseAudioContext&, size_t bufferSize, unsigned numberOfInputChannels, unsigned numberOfOutputChannels);
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bool virtualHasPendingActivity() const final;
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void eventListenersDidChange() final;
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void fireProcessEvent(unsigned bufferIndex);
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RefPtr<AudioBuffer> createInputBufferForJS(AudioBuffer*) const;
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RefPtr<AudioBuffer> createOutputBufferForJS(AudioBuffer&) const;
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// Double buffering.
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static constexpr unsigned bufferCount = 2;
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unsigned bufferIndex() const { return m_bufferIndex; }
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void swapBuffers() { m_bufferIndex = (m_bufferIndex + 1) % bufferCount; }
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unsigned m_bufferIndex { 0 };
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std::array<Lock, bufferCount> m_bufferLocks;
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std::array<RefPtr<AudioBuffer>, bufferCount> m_inputBuffers;
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std::array<RefPtr<AudioBuffer>, bufferCount> m_outputBuffers;
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mutable RefPtr<AudioBuffer> m_cachedInputBufferForJS;
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mutable RefPtr<AudioBuffer> m_cachedOutputBufferForJS;
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size_t m_bufferSize;
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unsigned m_bufferReadWriteIndex { 0 };
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unsigned m_numberOfInputChannels;
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unsigned m_numberOfOutputChannels;
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RefPtr<AudioBus> m_internalInputBus;
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bool m_hasAudioProcessEventListener { false };
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};
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} // namespace WebCore
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