Using oscillators with juce::AudioSource

Development
1

im following this tutorial Build a MIDI synthesiser - JUCE to make a synth. i got it to work following the tutorial but whated to add idfferent waves such as a square wave i thought this would be easy using a osilator class since i can use a lambda function for creating the wave i want simply.

so i tried it and it didnt work so i went along with the AudioProgrammers https://www.youtube.com/watch?v=AfrAWH5i-pQ&list=PLLgJJsrdwhPwJimt5vtHtNmu63OucmPck&index=3 tutorial which uses oscillators but in a plugin instead of an audio app.

so i’ve frnkensteind the two togther as far as i see reasonable but sound wont come out. im hitting the rendernext lock funtion in the audiovoice object and the buffer has stuff in it but i dont know why no sound is being produced.

#include "SineWaveVoice.h"
#include "SineWaveSound.h"

SineWaveVoice::SineWaveVoice(){}

void SineWaveVoice::PrepareToPlay(int samplesPerBlockExpected, double sampleRate, int numChannels) 
{

    adsr.setSampleRate(sampleRate);
    

    spec.numChannels = numChannels;
    spec.sampleRate = sampleRate;
    spec.maximumBlockSize = samplesPerBlockExpected;

    sineOsc.prepare(spec);
    gain.prepare(spec);
    //sineOsc.setFrequency(juce::MidiMessage::getMidiNoteInHertz(midiNoteNumber));
    sineOsc.setFrequency(220);
    gain.setGainLinear(0.1f);

    isPrepared = true;
}

bool SineWaveVoice::canPlaySound(juce::SynthesiserSound* sound)
{
    return dynamic_cast<SineWaveSound*> (sound) != nullptr;
}

void SineWaveVoice::startNote(int midiNoteNumber, float velocity, juce::SynthesiserSound*, int)
{
    
}

void SineWaveVoice::renderNextBlock(juce::AudioSampleBuffer& outputBuffer, int startSample, int numSamples)
{

    jassert(isPrepared);


    juce::dsp::AudioBlock<float> block{ outputBuffer };
    sineOsc.process(juce::dsp::ProcessContextReplacing<float>(block));
    gain.process(juce::dsp::ProcessContextReplacing<float>(block));

    adsr.applyEnvelopeToBuffer(outputBuffer, startSample, numSamples);
}

void SineWaveVoice::stopNote(float, bool allowTailOff)
{
    
    clearCurrentNote();
    
}


#include "synthAudioSource.h"
#include "sineWaveSound.h"
#include "sineWaveVoice.h"

synthAudioSource::synthAudioSource(juce::MidiKeyboardState& keyState) : keyboardState(keyState)
{
    for (auto i = 0; i < 4; ++i)
        synth.addVoice(new SineWaveVoice());
    synth.addSound(new SineWaveSound());
}

void synthAudioSource::setUsingSineWaveSound()
{
    synth.clearSounds();
}

void synthAudioSource::prepareToPlay(int samplesPerBlockExpected, double sampleRate)
{
    synth.setCurrentPlaybackSampleRate(sampleRate);
    midiCollector.reset(sampleRate);

    for (int i{}; i < synth.getNumVoices(); ++i) {
        if (auto voice = dynamic_cast<SineWaveVoice*>(synth.getVoice(i)))
        {
            voice->PrepareToPlay(samplesPerBlockExpected, sampleRate, 2);
        }
        
    }
}

void synthAudioSource::releaseResources()
{
}

void synthAudioSource::getNextAudioBlock(const juce::AudioSourceChannelInfo& bufferToFill)
{
    bufferToFill.clearActiveBufferRegion();
    juce::MidiBuffer incomingMidi;
    midiCollector.removeNextBlockOfMessages(incomingMidi, bufferToFill.numSamples);
    keyboardState.processNextMidiBuffer(incomingMidi, bufferToFill.startSample, bufferToFill.numSamples, true);
    synth.renderNextBlock(*bufferToFill.buffer, incomingMidi, bufferToFill.startSample, bufferToFill.numSamples);
}

juce::MidiMessageCollector* synthAudioSource::getMidiCollector()
{
    return &midiCollector;
}


#include "SineWaveSound.h"

SineWaveSound::SineWaveSound(){}

bool SineWaveSound::appliesToNote(int) { return true; }

bool SineWaveSound::appliesToChannel(int) { return true; }


#include "MainComponent.h"


//==============================================================================
MainComponent::MainComponent() : keyboardComponent(keyboardState, juce::MidiKeyboardComponent::horizontalKeyboard),
synthAudioSource(keyboardState)
{
    //midi keyboard
    addAndMakeVisible(keyboardComponent);

    setSize (200, 200);
    setAudioChannels (0, 2);
   
}

MainComponent::~MainComponent()
{
    shutdownAudio();
}

//==============================================================================

void MainComponent::prepareToPlay (int samplesPerBlockExpected, double sampleRate)
{
    synthAudioSource.prepareToPlay(samplesPerBlockExpected, sampleRate);
    
}

void MainComponent::getNextAudioBlock (const juce::AudioSourceChannelInfo& bufferToFill)
{ 
    synthAudioSource.getNextAudioBlock(bufferToFill);
}

void MainComponent::releaseResources()
{
    synthAudioSource.releaseResources();
}


//==============================================================================
void MainComponent::paint (juce::Graphics& g)
{}

void MainComponent::resized()
{
    keyboardComponent.setBounds(10, 40, getWidth() - 20, getHeight() - 50);
}

void MainComponent::timerCallback()
{
    keyboardComponent.grabKeyboardFocus();
    stopTimer();
}

sorry its a alot of code any guidence or critisism you give is appreaciated

2

I can’t really make sense of your code looking here in the browser, I’d need to copy and try building and running it to really see what might be wrong with it, but that’s a bit too much effort right now.

Is there a particular reason you want to develop your synth as a standalone application? You very likely could do it as a plugin too and build the standalone application version of it.

3

no reason to be honest just thought its something i shouldnt shy away from if im having issues, and im just setting up the git hub repo for it now. i always go a whke inbetween using git hub so i have to re learn how to set everything

4

GitHub - Kynanandkel/Synthesizer: A syth to practice juce stuff · GitHub here it is sorry that took so long :frowning:

5

figured it out. i had an adsr object applying an envelope but i thats not connected to the midi messages i dont think. so was just setting no window to the object

6

well sort of now it just continuously plays sound but hey ho one step forward hahaha kill me