renderNextBlock()?

General JUCE discussion
1

Hey Guys!, I’m new to juce and was following the tutorials on the juce website to making a synthesizer, for the renderNextblock() what exactly is numSamples?

 void renderNextBlock (AudioSampleBuffer& outputBuffer, int startSample, int numSamples) override
    {
        if (duration != 0.0)
        {
            if (tailOff > 0)
            {
                while (--numSamples >= 0)
                {
                    const float currentSample = setOscTypeWithTailOff();
                    
                    for (int i = outputBuffer.getNumChannels(); --i >= 0;)
                        outputBuffer.addSample (i, startSample, currentSample);
                    
                    phaseAngle += duration;
                    ++startSample;
                    
                    tailOff *= 0.99;
                    
                    if (tailOff <= 0.005)
                    {
                        clearCurrentNote();
                        
                        time = 0.0;
                    }
                }
            }
            else
            {
                while (--numSamples >= 0)
                {
                    const float currentSample = setOscType();
                    
                    for (int i = outputBuffer.getNumChannels(); --i >= 0;)
                        outputBuffer.addSample (i, startSample, currentSample);
                    
                    phaseAngle += duration;
                    ++startSample;
                }
            }
        }
    }
    ```
2

The (exact) number of audio samples you must render into the given AudioBuffer.

3

Alright and outputBuffer.getNumChannels is getting the channels for the buffer so do the channels contain the actual float values of my sinewave or does the buffer has it.

4

getNumChannels returns the number of channels (mono, stereo…) that the buffer handles. The code above just fills every channel with the same samples with the inner (for) loop. The outer (while) loop counts the number of samples that need to be rendered into the buffer.

5

Okay so where is the sinewave currentAngle value being plotted, I know its going through a loop to plot each angle in the cycle but im confused as to where that is actually happening.

6

I edited my answer above to explain the outer while loop does the sample iteration. currentAngle is advanced (with +=) for each sample. I would assume the functions that are called (setOscTypeWithTailOff, setOscType) to produce the samples will use currentAngle to calculate the desired sample values but I can’t say for sure based on the code you posted.