title: Vulkan off-screen rendering: TILING OPTIMAL or LINEAR
body: <p>I'd like to build a off-screen renderer using Vulkan and copying the rendering content to host memory in each frame.</p>
  
  <p>One scheme is using a frame image with TILING_OPTIMAL, and involving another copying render pass to copy the content to a host visible staging buffer.</p>
  
  <p>The other scheme is using a frame image with TILING_LINEAR, and copying from the image directly.</p>
  
  <p>I think the first scheme is more efficient, though involving one more copy step, but I'm not sure. And are there some more decent solutions?</p>
  
  <p>Thanks!</p>