JUCE/examples/PlugInSamples/GainPlugIn/Source/GainProcessor.cpp

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
   27th April 2017).

   End User License Agreement: www.juce.com/juce-5-licence
   Privacy Policy: www.juce.com/juce-5-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

#include "../JuceLibraryCode/JuceHeader.h"

//==============================================================================
/**
 */
class GainProcessor  : public AudioProcessor
{
public:

    //==============================================================================
    GainProcessor()
        : AudioProcessor (BusesProperties().withInput  ("Input",  AudioChannelSet::stereo())
                                           .withOutput ("Output", AudioChannelSet::stereo()))
    {
        addParameter (gain = new AudioParameterFloat ("gain", "Gain", 0.0f, 1.0f, 0.5f));
    }

    ~GainProcessor() {}

    //==============================================================================
    void prepareToPlay (double, int) override {}
    void releaseResources() override {}

    void processBlock (AudioBuffer<float>& buffer, MidiBuffer&) override
    {
        buffer.applyGain (*gain);
    }

    //==============================================================================
    AudioProcessorEditor* createEditor() override { return new GenericAudioProcessorEditor (this); }
    bool hasEditor() const override               { return true;   }

    //==============================================================================
    const String getName() const override               { return "Gain PlugIn"; }
    bool acceptsMidi() const override                   { return false; }
    bool producesMidi() const override                  { return false; }
    double getTailLengthSeconds() const override        { return 0; }

    //==============================================================================
    int getNumPrograms() override                          { return 1; }
    int getCurrentProgram() override                       { return 0; }
    void setCurrentProgram (int) override                  {}
    const String getProgramName (int) override             { return String(); }
    void changeProgramName (int , const String& ) override { }

    //==============================================================================
    void getStateInformation (MemoryBlock& destData) override
    {
        MemoryOutputStream (destData, true).writeFloat (*gain);
    }

    void setStateInformation (const void* data, int sizeInBytes) override
    {
        gain->setValueNotifyingHost (MemoryInputStream (data, static_cast<size_t> (sizeInBytes), false).readFloat());
    }

    //==============================================================================
    bool isBusesLayoutSupported (const BusesLayout& layouts) const override
    {
        const AudioChannelSet& mainInLayout  = layouts.getChannelSet (true,  0);
        const AudioChannelSet& mainOutLayout = layouts.getChannelSet (false, 0);

        return (mainInLayout == mainOutLayout && (! mainInLayout.isDisabled()));
    }

private:
    //==============================================================================
    AudioParameterFloat* gain;

    enum { kVST2MaxChannels = 16 };

    //==============================================================================
    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (GainProcessor)
};

//==============================================================================
// This creates new instances of the plugin..
AudioProcessor* JUCE_CALLTYPE createPluginFilter()
{
    return new GainProcessor();
}