title: Projecting equirectangular image onto a plane
body: <p>Given a 3D cuboid and an equirectangular image, I want to map the image onto the inside of a cuboid (only the side faces, not top or bottom). To do this I want to create textures for each face of the cuboid from the equirectangular image.</p>
  
  <p>The image is from a room and I have labelled the top and bottom corners in the panorama which correspond to corners of my cuboid. The image is not from the inside of the room and I wish to create a texture for each face.</p>
  
  <p>I tried solution given here: <a href="https://stackoverflow.com/questions/29678510/convert-21-equirectangular-panorama-to-cube-map/29681646#29681646">Convert 2:1 equirectangular panorama to cube map</a></p>
  
  <p>But that is for a cube, where each texture is the same size. I have looked at other resources but I feel I need another explanation such that I can fully understand how to do this.</p>
  
  <p>Thanks!</p>