Digital Signal Processing

float[] rawData;

void setup() {
  size(1400, 800);
  
  rawData = randomData(128);
}

void draw() {
  float interval = map(mouseX, 0, width, 0, 1);
  float timeConstant = map(mouseY, 0, height, 0, 1);
  
  float[] lowPassed = lowPass(rawData, interval, timeConstant);
  
  background(0);
  
  drawLine(rawData, color(127));
  drawLine(lowPassed, color(255, 255, 0));
}

float[] randomData(int size) {
  float[] data = new float[size];
  
  for(int i=0; i < data.length; i++) {
    data[i] = noise(i);
  }
  
  return data;
}

void drawLine(float[] data, color c) {
  noFill();
  stroke(c);
  
  beginShape();
  
  for (int i=0; i < data.length; i++) {
    vertex(map(i, 0, data.length, 0, width), map(data[i], 0, 1, 0, height));
  }
  
  endShape();
}

float[] lowPass(float[] in, float interval, float timeConstant) {
  float[] out = new float[in.length];
  
  float alpha = interval / (timeConstant + interval);
  
  out[0] = in[0];
  for (int i=1; i < in.length; i++) { 
    out[i] = alpha * in[i] + (1 - alpha) * out[i-1];
  }
  
  return out;
}