title: Threejs partially applied texture
body: <p>I'm trying to do a partially applied texture with shaders on a teapot in ThreeJS. Currently it looks like this: <a href="https://i.stack.imgur.com/PmFCh.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PmFCh.png" alt="enter image description here"></a></p>
  
  <p>I need it to look like this: <a href="https://i.stack.imgur.com/WF6Py.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WF6Py.png" alt="enter image description here"></a></p>
  
  <p>But I'm not sure how I should approach this, do I do that clipping with shader itself, or threejs code? I can't figgure out the basic idea of how to do this.</p>