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 "platform/audio/AudioUtilities.h"
32 #include "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
AudioDestinationNode(AudioContext * context,float sampleRate)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
~AudioDestinationNode()49 AudioDestinationNode::~AudioDestinationNode()
50 {
51 uninitialize();
52 }
53
render(AudioBus * sourceBus,AudioBus * destinationBus,size_t numberOfFrames)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()->isInitialized()) {
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