def calcMatrix(): Matrix4d = {
  val m = new Matrix4d()
  m.setIdentity()
  val quad = renderingQuad

  // GUI scale
  val guiScale = new Matrix4d(
    1d / pixelSize.width, 0, 0, 0,
    0, 1d / pixelSize.height, 0, 0,
    0, 0, 1, 0,
    0, 0, 0, 1
  )
  m.mul(guiScale)
  // End GUI scale

  // Quad scale
  val quadScale = new Matrix4d(
    (quad._2 - quad._1).mag, 0, 0, 0,
    0, (quad._4 - quad._1).mag, 0, 0,
    0, 0, 1, 0,
    0, 0, 0, 1
  )
  m.mul(quadScale)
  // Quad scale

  // Rotate
  val v0 = quad._1.normalize

  val xAxis = Vector3(1, 0, 0)
  val xRotated = v0 cross xAxis
  val xW = (v0 dot xAxis) + math.sqrt(v0.mag * v0.mag + xAxis.mag * xAxis.mag)

  val q = new Quat4d()

  q.set(xRotated.x, xRotated.y, xRotated.z, xW)
  q.normalize()
  val xM = new Matrix4d()
  xM.set(q)

  val yAxis = Vector3(0, 1, 0)
  val yRotated = v0 cross yAxis
  val yW = (v0 dot yAxis) + math.sqrt(v0.mag * v0.mag + yAxis.mag * yAxis.mag)

  q.set(yRotated.x, yRotated.y, yRotated.z, yW)
  q.normalize()
  val yM = new Matrix4d()
  yM.set(q)
  yM.invert()

  xM.mul(yM)
  m.mul(xM)
  // End Rotate

  // Translate
  val translate = new Matrix4d(
    1, 0, 0, quad._1.x,
    0, 1, 0, quad._1.y,
    0, 0, 1, quad._1.z,
    0, 0, 0, 1
  )
  m.mul(translate)
  // End Translate

  m
}