Re: Ada and OpenGL

["Maxim Reznik" <max1@mbank.com.ua>]

"Michael Andersson" <a98mican@ida.his.se> wrote in message news:3BB4EB06.FCED0102@ida.his.se...
> Hi!
> Could somebody please show me how to use the glGetString function with
> Ada?
> I get Storage Error every time and I guess it has to do with illegal
> memory access.
>
> Thanks in advance!
> /Michael Andersson

I use this code:

with gl; use gl;
with glut; use glut;
with Interfaces.C.Strings; use Interfaces.C.Strings;
with Ada.Unchecked_Conversion;
with Text_IO; use Text_IO;

procedure GL_Test is

  function to_char_ptr
    is new Ada.Unchecked_Conversion( GLubytePtr, chars_ptr);

  procedure PrintInfo is
  begin
    Put("VENDOR=");
    put_Line( Value(
               to_char_ptr( glGetString( GL_VENDOR ) )));
  end;


  type chars_ptr_ptr is access Interfaces.C.Strings.chars_ptr;


  argc : aliased integer;
  pragma Import (C, argc, "gnat_argc");

  argv : chars_ptr_ptr;
  pragma Import (C, argv, "gnat_argv");


    win: Integer;
  begin

     glutInitDisplayMode(GLUT_RGB or GLUT_DEPTH or GLUT_DOUBLE);
     glutInit (argc'access, argv);
     win:=glutCreateWindow("test 1");
     PrintInfo;

end;