function initBuffers(gl) {
  const positionBuffer = initPositionBuffer(gl);

  return {
    position: positionBuffer,
  };
}

function initPositionBuffer(gl) {
  // Position array of a "full-screen" quad (encoded as TRIANGLE_STRIP)
  // Ref: https://en.wikipedia.org/wiki/Triangle_strip
  // NOTE: +x,+y is top-right & -x,-y is bottom-left
  const positions = [
    -1.0,  1.0,
    -1.0, -1.0,
     1.0,  1.0,
     1.0, -1.0,
  ];

  // Create a buffer for the square's positions.
  const positionBuffer = gl.createBuffer();
  // Select the positionBuffer as the one to apply buffer
  // operations to from here out.
  gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
  // Now pass the list of positions into WebGL to build the
  // shape. We do this by creating a Float32Array from the
  // JavaScript array, then use it to fill the current buffer.
  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(positions), gl.STATIC_DRAW);

  return positionBuffer;
}

export { initBuffers };