// 

// Using the sin function to generate patterns. 

// Adapted from the Processing handbook.

​

function setup() {

  createCanvas(700, 100);

  background(220);

​

  // How much to scale the sin wave pattern in the y-direction

  // (the amplitude)

  let scaleVal = 35;

​

  // The centre line of the sin wave.

  let offset = 50;

​

  // The angle that we will sample the sin value for.

  // This will increase along the x-axis by 'angleInc' each step.

  let angle = 0;

  let angleInc = TWO_PI / 93;

​

  beginShape(TRIANGLE_STRIP);

​

  for (let x = 0; x <= width; x = x + 5) { 

    // Calculate the y position based on the sin of the angle.

    let y = sin(angle) * scaleVal;

    // Every even time through the loop place a vertex at the bottom

    if ((x % 2) == 0) { 

      vertex(x, offset + y);      

    } else {

      // Otherwise, place a vertex at the top

      vertex(x, offset - y);

    }

​

    // Increase the angle each step. 

    angle = angle + angleInc;

  }

​

  endShape();

}