gecko/content/media/webaudio/AudioParamTimeline.h

76 lines
2.2 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef AudioParamTimeline_h_
#define AudioParamTimeline_h_
#include "AudioEventTimeline.h"
#include "mozilla/ErrorResult.h"
#include "nsAutoPtr.h"
#include "MediaStreamGraph.h"
#include "AudioSegment.h"
namespace mozilla {
namespace dom {
// This helper class is used to represent the part of the AudioParam
// class that gets sent to AudioNodeEngine instances. In addition to
// AudioEventTimeline methods, it holds a pointer to an optional
// MediaStream which represents the AudioNode inputs to the AudioParam.
// This MediaStream is managed by the AudioParam subclass on the main
// thread, and can only be obtained from the AudioNodeEngine instances
// consuming this class.
class AudioParamTimeline : public AudioEventTimeline<ErrorResult>
{
typedef AudioEventTimeline<ErrorResult> BaseClass;
public:
explicit AudioParamTimeline(float aDefaultValue)
: BaseClass(aDefaultValue)
{
}
MediaStream* Stream() const
{
return mStream;
}
bool HasSimpleValue() const
{
return BaseClass::HasSimpleValue() && !mStream;
}
// Get the value of the AudioParam at time aTime + aCounter.
// aCounter here is an offset to aTime if we try to get the value in ticks,
// otherwise it should always be zero. aCounter is meant to be used when
// getting the value of an a-rate AudioParam for each tick inside an
// AudioNodeEngine implementation.
template<class TimeType>
float GetValueAtTime(TimeType aTime, size_t aCounter = 0) const
{
MOZ_ASSERT(aCounter < WEBAUDIO_BLOCK_SIZE);
MOZ_ASSERT(!aCounter || !HasSimpleValue());
// Mix the value of the AudioParam itself with that of the AudioNode inputs.
return BaseClass::GetValueAtTime(static_cast<TimeType>(aTime + aCounter)) +
(mStream ? AudioNodeInputValue(aCounter) : 0.0f);
}
private:
float AudioNodeInputValue(size_t aCounter) const;
protected:
// This is created lazily when needed.
nsRefPtr<MediaStream> mStream;
};
}
}
#endif