1 /* 2 * Copyright (C) 2010, Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY 17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23 */ 24 25 #include "config.h" 26 27 #if ENABLE(WEB_AUDIO) 28 29 #include "modules/webaudio/AudioDestinationNode.h" 30 31 #include "core/platform/audio/AudioUtilities.h" 32 #include "core/platform/audio/DenormalDisabler.h" 33 #include "modules/webaudio/AudioContext.h" 34 #include "modules/webaudio/AudioNodeInput.h" 35 #include "modules/webaudio/AudioNodeOutput.h" 36 37 namespace WebCore { 38 39 AudioDestinationNode::AudioDestinationNode(AudioContext* context, float sampleRate) 40 : AudioNode(context, sampleRate) 41 , m_currentSampleFrame(0) 42 { 43 ScriptWrappable::init(this); 44 addInput(adoptPtr(new AudioNodeInput(this))); 45 46 setNodeType(NodeTypeDestination); 47 } 48 49 AudioDestinationNode::~AudioDestinationNode() 50 { 51 uninitialize(); 52 } 53 54 void AudioDestinationNode::render(AudioBus* sourceBus, AudioBus* destinationBus, size_t numberOfFrames) 55 { 56 // We don't want denormals slowing down any of the audio processing 57 // since they can very seriously hurt performance. 58 // This will take care of all AudioNodes because they all process within this scope. 59 DenormalDisabler denormalDisabler; 60 61 context()->setAudioThread(currentThread()); 62 63 if (!context()->isRunnable()) { 64 destinationBus->zero(); 65 return; 66 } 67 68 // Let the context take care of any business at the start of each render quantum. 69 context()->handlePreRenderTasks(); 70 71 // Prepare the local audio input provider for this render quantum. 72 if (sourceBus) 73 m_localAudioInputProvider.set(sourceBus); 74 75 // This will cause the node(s) connected to us to process, which in turn will pull on their input(s), 76 // all the way backwards through the rendering graph. 77 AudioBus* renderedBus = input(0)->pull(destinationBus, numberOfFrames); 78 79 if (!renderedBus) 80 destinationBus->zero(); 81 else if (renderedBus != destinationBus) { 82 // in-place processing was not possible - so copy 83 destinationBus->copyFrom(*renderedBus); 84 } 85 86 // Process nodes which need a little extra help because they are not connected to anything, but still need to process. 87 context()->processAutomaticPullNodes(numberOfFrames); 88 89 // Let the context take care of any business at the end of each render quantum. 90 context()->handlePostRenderTasks(); 91 92 // Advance current sample-frame. 93 m_currentSampleFrame += numberOfFrames; 94 } 95 96 } // namespace WebCore 97 98 #endif // ENABLE(WEB_AUDIO) 99
