code: func Bounds(x, y, w, h int) {
  	gl.Viewport(int32(x), int32(y), int32(w), int32(h))
  	gl.Scissor(int32(x), int32(y), int32(w), int32(h))
  }
docs: // Bounds sets the drawing bounds in pixels. Drawing outside bounds is always discarted.
  //
  // Calling this function is equivalent to setting viewport and scissor in OpenGL.