Simple sinewave generator/writer example

sinewaveWriter.cpp

/*
replace your initialize() in your juce GUI project with this
*/

    void initialise (const String& commandLine) override
    {
        // This method is where you should put your application's initialisation code..
        /*
         we're going to write a 2-second long 16-bit wave file to disk.
         */
        MemoryBlock block(44100 * 2 * sizeof(uint16), true);
        AudioBuffer<float> buffer(1, static_cast<int>(block.getSize() / sizeof(uint16)));

        AudioDataConverters::convertInt16LEToFloat(block.getData(),
                                                   buffer.getWritePointer(0),
                                                   buffer.getNumSamples());

        //write a 440hz sinewave to the buffer
        auto* writePointer = buffer.getWritePointer(0);
        struct SineState
        {
            float currentSampleRate = 44100.f;
            float currentAngle = 0.f;
            float cyclesPerSample = 440.f / currentSampleRate;
            float angleDelta = cyclesPerSample * MathConstants<float>::twoPi;
        };
        SineState sineState;
        for( int i = 0; i < buffer.getNumSamples(); ++i  )
        {
            auto currentSample = static_cast<float>(std::sin(sineState.currentAngle));
            sineState.currentAngle += sineState.angleDelta; //fine if it wrapps around
            writePointer[i] = currentSample * 0.5f;
        }

        //save the buffer to disk
        File audioFile (File::getSpecialLocation(File::SpecialLocationType::currentApplicationFile).getSiblingFile("test").withFileExtension(".aiff"));
        audioFile.deleteFile();
        audioFile.create();
        if( audioFile.existsAsFile() )
        {
            ScopedPointer<FileOutputStream> fos(audioFile.createOutputStream());
            if( fos->openedOk() )
            {
                AiffAudioFormat aiff;
                ScopedPointer<AudioFormatWriter> writer(aiff.createWriterFor(fos.get(),
                                                                             44100,
                                                                             1,
                                                                             16,
                                                                             {},
                                                                             0));
                if( writer != nullptr )
                {
                    fos.release();
                    if( writer->writeFromAudioSampleBuffer(buffer, 0, buffer.getNumSamples()) )
                    {
                        audioFile.revealToUser();
                    }
                    else
                    {
                        jassertfalse; //failed to write
                    }
                }
                else
                {
                    jassertfalse; //failed to create writer
                }
            }
        }
        jassertfalse; //go ahead and check your audio file in your DAW.
        mainWindow = new MainWindow (getApplicationName());
    }