[cello-devel] Re: cl-opengl/hello-c: make-ff-pointer problem on OS X / Allegro: Pse help

[Kenny Tilton]

Frank Goenninger - PRION Consulting wrote:

> Kenny & all:
>
> now that I am able to use ACL 7.0 and as I am currently re-porting  
> Cello to OS X I ran into a problem with make-ff-pointer:
>
> When calling the make-ff-pointer function in order to get a ffi-glut- 
> id for a font the function just returns the value passed to it. This  
> is wrong and causes the following bus error:
>
> ------
>
> Received signal number 10 (Bus error)
>    [Condition of type SYNCHRONOUS-OPERATING-SYSTEM-SIGNAL]
>
> Backtrace:
>   0: (SWANK::DEBUG-IN-EMACS #<SYNCHRONOUS-OPERATING-SYSTEM-SIGNAL @  
> #x5831c02>)
>   1: (SWANK:SWANK-DEBUGGER-HOOK #<SYNCHRONOUS-OPERATING-SYSTEM- SIGNAL 
> @ #x5831c02> #<Function SWANK-DEBUGGER-HOOK>)
>   2: (ERROR SYNCHRONOUS-OPERATING-SYSTEM-SIGNAL :NAME #1="Bus  error" 
> :NUMBER 10 :FORMAT-CONTROL "Received signal number ~s ~@[(~a) ~]" 
> :FORMAT-ARGUMENTS (10 #1#))
>   3: (CL-OPENGL:GLUTSTROKECHARACTER #<FOREIGN-FUNCTIONS:FOREIGN- 
> POINTER NIL #x0 @ #x5831752> 78)
>   4: (CL-OPENGL:GLUT-STROKE-CHARACTER #<FOREIGN-FUNCTIONS:FOREIGN- 
> POINTER NIL #x0 @ #x5831752> 78)
>   5: (CL-OPENGL:GLUT-STROKE-STRING #<FOREIGN-FUNCTIONS:FOREIGN- 
> POINTER NIL #x0 @ #x5831752> "NeHe - 0.0")
>   6: ((:INTERNAL CL-OPENGL::NH14-DISP 0))
>
> ------
>
> I modified function make-ff-pointer as follows:
>
> (defun make-ff-pointer (n)
>   #+allegro   (ff:make-foreign-pointer :address n :type '(* void))
>   #+lispworks (fli:make-pointer :address n :pointer-type  '(:pointer 
> :void))
>   #-(or lispworks allegro) n
> )
>
> As you can see from the backtrace the function in question is CL- 
> OPENGL:GLUT-STROKE-STRING which gets called from within  NH14-DISP.   
> What is needed as the first parameter is a _pointer_ to a font...  
> Now, how to do that - I am stuck... 

I am investigating, but real quick: Freeglut lies. :) What is wanted is 
an integer, an enum kinda thing, 0,1,2 --- they are hard-coded to mean 
certain limited fonts Freeglut knows about.

kt