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/*
* 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
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "modules/webaudio/GainNode.h"
#include "modules/webaudio/AudioNodeInput.h"
#include "modules/webaudio/AudioNodeOutput.h"
#include "platform/audio/AudioBus.h"
namespace blink {
GainHandler::GainHandler(AudioNode& node, float sampleRate, AudioParamHandler& gain)
: AudioHandler(NodeTypeGain, node, sampleRate)
, m_lastGain(1.0)
, m_gain(gain)
, m_sampleAccurateGainValues(ProcessingSizeInFrames) // FIXME: can probably share temp buffer in context
{
addInput();
addOutput(1);
initialize();
}
PassRefPtr<GainHandler> GainHandler::create(AudioNode& node, float sampleRate, AudioParamHandler& gain)
{
return adoptRef(new GainHandler(node, sampleRate, gain));
}
void GainHandler::process(size_t framesToProcess)
{
// FIXME: for some cases there is a nice optimization to avoid processing here, and let the gain change
// happen in the summing junction input of the AudioNode we're connected to.
// Then we can avoid all of the following:
AudioBus* outputBus = output(0).bus();
ASSERT(outputBus);
if (!isInitialized() || !input(0).isConnected()) {
outputBus->zero();
} else {
AudioBus* inputBus = input(0).bus();
if (m_gain->hasSampleAccurateValues()) {
// Apply sample-accurate gain scaling for precise envelopes, grain windows, etc.
ASSERT(framesToProcess <= m_sampleAccurateGainValues.size());
if (framesToProcess <= m_sampleAccurateGainValues.size()) {
float* gainValues = m_sampleAccurateGainValues.data();
m_gain->calculateSampleAccurateValues(gainValues, framesToProcess);
outputBus->copyWithSampleAccurateGainValuesFrom(*inputBus, gainValues, framesToProcess);
}
} else {
// Apply the gain with de-zippering into the output bus.
if (!m_lastGain && m_lastGain == m_gain->value()) {
// If the gain is 0 (and we've converged on dezippering), just zero the bus and set
// the silence hint.
outputBus->zero();
} else {
outputBus->copyWithGainFrom(*inputBus, &m_lastGain, m_gain->value());
}
}
}
}
// FIXME: this can go away when we do mixing with gain directly in summing junction of AudioNodeInput
//
// As soon as we know the channel count of our input, we can lazily initialize.
// Sometimes this may be called more than once with different channel counts, in which case we must safely
// uninitialize and then re-initialize with the new channel count.
void GainHandler::checkNumberOfChannelsForInput(AudioNodeInput* input)
{
ASSERT(context()->isAudioThread());
ASSERT(context()->isGraphOwner());
ASSERT(input);
ASSERT(input == &this->input(0));
if (input != &this->input(0))
return;
unsigned numberOfChannels = input->numberOfChannels();
if (isInitialized() && numberOfChannels != output(0).numberOfChannels()) {
// We're already initialized but the channel count has changed.
uninitialize();
}
if (!isInitialized()) {
// This will propagate the channel count to any nodes connected further downstream in the graph.
output(0).setNumberOfChannels(numberOfChannels);
initialize();
}
AudioHandler::checkNumberOfChannelsForInput(input);
}
// ----------------------------------------------------------------
GainNode::GainNode(AbstractAudioContext& context, float sampleRate)
: AudioNode(context)
, m_gain(AudioParam::create(context, 1.0))
{
setHandler(GainHandler::create(*this, sampleRate, m_gain->handler()));
}
GainNode* GainNode::create(AbstractAudioContext& context, float sampleRate)
{
return new GainNode(context, sampleRate);
}
AudioParam* GainNode::gain() const
{
return m_gain;
}
DEFINE_TRACE(GainNode)
{
visitor->trace(m_gain);
AudioNode::trace(visitor);
}
} // namespace blink
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