// When the mouse is pressed, the string gets excited.

let slider;

let audioCtx = new AudioContext();

let delayLength = 100; // this is the frequency of the string

let delayline = new Array([]);

let pos = 0;

source = audioCtx.createBufferSource();

​

// Create a ScriptProcessorNode with a bufferSize, input, output channels

let scriptNode = audioCtx.createScriptProcessor(1024, 1, 1);

​

function setup() {

    background(0);

​

    slider = createSlider(0, 100, 50);

    source.connect(scriptNode);

    scriptNode.connect(audioCtx.destination);

    source.start();

}

​

function mousePressed() {

    // fill the delay line with noise when the mouse is pressed

  for (let i = 0; i < delayLength; i++) {

        delayline[i] = ((Math.random() * 2) - 1) * 0.5;

    }

}

​

​

// Give the node a function to process audio events

scriptNode.onaudioprocess = function(audioProcessingEvent) {

    let inputBuffer = audioProcessingEvent.inputBuffer;

​

    let volume = slider.value() / 100;

    // The output buffer contains the samples that will be modified and played

    let outputBuffer = audioProcessingEvent.outputBuffer;

​

    // Loop through the output channels (in this case there is only one)

    for (let channel = 0; channel < outputBuffer.numberOfChannels; channel++) {

        //var inputData = inputBuffer.getChannelData(channel);

        let outputData = outputBuffer.getChannelData(channel);

​

        // Loop through the 1024 samples

        for (let sample = 0; sample < inputBuffer.length; sample++) {

            // update to the next position in the delay line 

            let nextPos = (pos + 1) % delayLength;

            // lowpass filter the delayline 

            delayline[nextPos] = 0.5 * (delayline[nextPos] + delayline[pos]);

            // scale output

            outputData[sample] = delayline[pos] * volume;

            pos = nextPos;

        }

    }

}