title: coordinates system problem with jogl
body: <p>Currently I am developing an application in Jogl(My first application actually).
  Frist I have to load model into the canvas from a .obj file.(I manage to do so).</p>
  
  <p>Next is I have to use the mouse dragged event to draw stroke on the same canvans and it the stroke must be in front of the teapot.(I use GL.GL_LINE_STRIP)and (glu.gluUnproject to get the coordinates to draw on)</p>
  
  <p>Till this point I am having problems.
  (The model is just a rod laying horitontally on the x axis)</p>
  
  <p>The coordinates of the model that is loaded does not seems the same as the mu mouse cursor point. For example: I use mouse click to determine where my cursor is at and also I click at the end of my model(a rod).This returns mi the X value of 0.37599047216147075. 
  Then I try to look for the Maximum vertex X value of the rod model(should be the vertex at the most right hand side of the rod). it returns me a 1.xxx value... which is no where close to my mouse cursor value. And the maximum value I can click is just only 0.6xxx. Any idea why is this so?</p>