title: Convert stack of 2d images into 3d image, volume rendering
body: <p>I want to do a texture based volume render of CT data. I have a stack of 2d CT images that I'd like to use as a 3d texture in opengl (jogl really). I have to do it the way with polygon proxy geometry that shifts when viewing parameters change. How can I convert the 2d images to one 3d texture? I have not been able to find anything about how opengl expects 3d images to be formatted. I saw this: <a href="https://stackoverflow.com/questions/13509191/how-to-convert-2d-image-into-3d-image">https://stackoverflow.com/questions/13509191/how-to-convert-2d-image-into-3d-image</a> , but I don't it's the same.</p>
  
  <p>Also, I am still in confusion about this volume rendering technique. Is it possible to take a 3d location in the 3d texture and map it to a 2d corner of a quad? I found this example: <a href="http://www.felixgers.de/teaching/jogl/texture3D.html" rel="nofollow noreferrer">http://www.felixgers.de/teaching/jogl/texture3D.html</a> but I don't know if it means you have to use 3d vertices. Does anyone know more sources with explicit examples?</p>