137 lines
5.8 KiB
C++
137 lines
5.8 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2017 - ROLI Ltd.
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JUCE is an open source library subject to commercial or open-source
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licensing.
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By using JUCE, you agree to the terms of both the JUCE 5 End-User License
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Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
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27th April 2017).
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End User License Agreement: www.juce.com/juce-5-licence
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Privacy Policy: www.juce.com/juce-5-privacy-policy
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Or: You may also use this code under the terms of the GPL v3 (see
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www.gnu.org/licenses).
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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//==============================================================================
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/**
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A base class for writing audio apps that stream from the audio i/o devices.
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Conveniently combines a Component with an AudioSource to provide a starting
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point for your audio applications.
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A subclass can inherit from this and implement just a few methods such as
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getNextAudioBlock(). The base class provides a basic AudioDeviceManager object
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and runs audio through the default output device.
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An application should only create one global instance of this object and multiple
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classes should not inherit from this.
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This class should not be inherited when creating a plug-in as the host will
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handle audio streams from hardware devices.
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@tags{Audio}
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*/
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class JUCE_API AudioAppComponent : public Component,
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public AudioSource
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{
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public:
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AudioAppComponent();
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AudioAppComponent (AudioDeviceManager&);
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~AudioAppComponent();
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/** A subclass should call this from their constructor, to set up the audio. */
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void setAudioChannels (int numInputChannels, int numOutputChannels, const XmlElement* const storedSettings = nullptr);
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/** Tells the source to prepare for playing.
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An AudioSource has two states: prepared and unprepared.
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The prepareToPlay() method is guaranteed to be called at least once on an 'unpreprared'
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source to put it into a 'prepared' state before any calls will be made to getNextAudioBlock().
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This callback allows the source to initialise any resources it might need when playing.
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Once playback has finished, the releaseResources() method is called to put the stream
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back into an 'unprepared' state.
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Note that this method could be called more than once in succession without
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a matching call to releaseResources(), so make sure your code is robust and
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can handle that kind of situation.
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@param samplesPerBlockExpected the number of samples that the source
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will be expected to supply each time its
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getNextAudioBlock() method is called. This
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number may vary slightly, because it will be dependent
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on audio hardware callbacks, and these aren't
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guaranteed to always use a constant block size, so
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the source should be able to cope with small variations.
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@param sampleRate the sample rate that the output will be used at - this
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is needed by sources such as tone generators.
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@see releaseResources, getNextAudioBlock
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*/
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virtual void prepareToPlay (int samplesPerBlockExpected,
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double sampleRate) = 0;
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/** Allows the source to release anything it no longer needs after playback has stopped.
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This will be called when the source is no longer going to have its getNextAudioBlock()
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method called, so it should release any spare memory, etc. that it might have
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allocated during the prepareToPlay() call.
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Note that there's no guarantee that prepareToPlay() will actually have been called before
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releaseResources(), and it may be called more than once in succession, so make sure your
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code is robust and doesn't make any assumptions about when it will be called.
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@see prepareToPlay, getNextAudioBlock
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*/
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virtual void releaseResources() = 0;
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/** Called repeatedly to fetch subsequent blocks of audio data.
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After calling the prepareToPlay() method, this callback will be made each
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time the audio playback hardware (or whatever other destination the audio
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data is going to) needs another block of data.
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It will generally be called on a high-priority system thread, or possibly even
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an interrupt, so be careful not to do too much work here, as that will cause
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audio glitches!
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@see AudioSourceChannelInfo, prepareToPlay, releaseResources
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*/
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virtual void getNextAudioBlock (const AudioSourceChannelInfo& bufferToFill) = 0;
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/** Shuts down the audio device and clears the audio source.
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This method should be called in the destructor of the derived class
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otherwise an assertion will be triggered.
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*/
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void shutdownAudio();
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AudioDeviceManager& deviceManager;
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private:
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//=============================================================================
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AudioDeviceManager defaultDeviceManager;
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AudioSourcePlayer audioSourcePlayer;
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bool usingCustomDeviceManager;
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JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AudioAppComponent)
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};
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} // namespace juce
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