title: Display voxels using shaders in openGL
body: <p>I am working on voxelisation using the rendering pipeline and now I successfully voxelise the scene using vertex+geometry+fragment shaders. Now my voxels are stored in a 3D texture which has size, for example, 128x128x128. </p>
  
  <p>My original model of the scene is centered at (0,0,0) and it extends in both positive and negative axis. The texure, however, is centered at (63,63,63) in tex coordinates.</p>
  
  <p>I implemented a simple ray marcing for visualizing but it doesn't take into account the camera movements (I can render only from very fixed positions because my ray have to be generated taking into account the different coordinates of the 3D texture).</p>
  
  <p>My question is: how can I map my rays so that they are generated at point Po with direction D in the coordinates of my 3D model but intersect the voxels at the corresponding position in texture coordinates and every movement of the camera in the 3D world is remapped in the voxel coordinates?</p>
  
  <p>Right now I generate the rays in this way:
  create a quad in front of the camera at position (63,63,-20)
  cast rays in direction towards (63,63,3)</p>