code: func (i *Image) makeVolatile() {
  	if i.isDisposed() {
  		return
  	}
  	i.mipmap.orig.MakeVolatile()
  	i.disposeMipmaps()
  }
docs: // makeVolatile makes the image 'volatile'.
  // A volatile image is always cleared at the start of a frame.
  //
  // This is suitable for offscreen images that pixels are changed often.
  //
  // Regular non-volatile images need to record drawing history or read its pixels from GPU if necessary so that all
  // the images can be restored automatically from the context lost. However, such recording the drawing history or
  // reading pixels from GPU are expensive operations. Volatile images can skip such oprations, but the image content
  // is cleared every frame instead.
  //
  // When the image is disposed, makeVolatile does nothing.