I want to use gluUnProject in order to do things on-screen when the user clicks with the mouse.  I&#39;m using Ubuntu, and it seems that the opengl libraries that come with it do not come with the glu(Un)Project methods defined.  However, after poking around a bit in the source, it looks pretty straight-forward to create the lisp methods from the c methods, so I added the following to my glu.lisp file:<br>
<br>(def-foreign-routine (&quot;gluProject&quot; project) void<br>  (obj-x gl:double)<br>  (obj-y gl:double)<br>  (obj-z gl:double)<br>  (modelview (* gl:double)<br>  (projection (* gl:double)<br>  (viewport (* gl:int))<br>
  (win-x (* gl:double)<br>  (win-y (* gl:double)<br>  (win-z (* gl:double)))))))<br>  <br>(def-foreign-routine (&quot;gluUnProject&quot; unproject) void<br>  (win-x gl:double)<br>  (win-y gl:double)<br>  (win-z gl:double)<br>
  (modelview (* gl:double)<br>  (projection (* gl:double)<br>  (viewport (* gl:int))<br>  (obj-x (* gl:double)<br>  (obj-y (* gl:double)<br>  (obj-z (* gl:double)))))))<br><br>These are purely based off of looking around at how the other glu methods were defined. <br>
<br>Are these definitions correct?  I&#39;m unable to really try them out because I don&#39;t understand how to pass double pointers to these methods.  I&#39;m just getting started with CL, and loving it so far, but the application I&#39;m currently working on has definitely hit a roadblock.<br>
<br>Can somone point me in the right direction as far as whether how I&#39;m defining these methods is correct, and if so, how I pass pointer-style vars to the method calls to get the results?<br><br>Thanks!<br>