Re: Need Help With GLUT (Apex NT 4.2.0)

["Randy Brukardt" <randy@rrsoftware.com>]

I don't know anything much about GLUT, but I doubt that the error has
anything to do with that. The error message is fairly clear:
"Render_Scene is not subtype conformant". All this means is that the
subtypes of the parameters of Render_Scene don't match the ones expected
for the access type that you are converting it to. Since Render_Scene
doesn't have any parameters at all, I suspect that the access type does,
and thus you get an error.

Ada checks that the parameters match, so that you (or GLUT in this case)
can't call a routine with one set of parameters that is expecting a
different set.

         Randy.


Nelson Chandler wrote in message ...
>Hello All,
>
>I'm trying to learn OpenGL using Ada on a Win2k machine.
>When I try to compile the following, I get "Render_Scene is not subtype
>conformant with procedure [RM_95 3.10.2(32)]".  This is an example from
>"OpenGL SuperBible (2nd ed)" converted (by me) to the general format of
the
>sample gnat Ada programs that came with GLUT.  I'm using Apex Ada NT
4.2.0.
>Can any of you tell me what's wrong and how to fix it?  Thank you.
>
>-Nelson
>
>--
>-- File Name: simple.2.ada
>--
>
>with Glut;
>use Glut;
>with Gl;
>with Simple_Procs;
>
>procedure Simple is
>    Dont_Care : Integer;
>begin
>
>    Glutinitdisplaymode (Glut_Single or Glut_Rgb);
>    Dont_Care := Glutcreatewindow ("Simple");
>    Glutdisplayfunc (Simple_Procs.Render_Scene'Access);  --COMPILER
ERROR IS
>HERE
>
>    Gl.Glclearcolor (0.0, 0.0, 1.0, 1.0);
>
>    Glutmainloop;
>
>end Simple;
>
>--
>-- File Name: simple_procs.1.ada
>--
>with Glut;
>
>package Simple_Procs is
>    procedure Render_Scene;
>end Simple_Procs;
>
>--
>-- File Name: simple_procs.2.ada
>--
>with Gl;
>package body Simple_Procs is
>    procedure Render_Scene is
>    begin
>        Gl.Glclear (Gl.Gl_Color_Buffer_Bit);
>        Gl.Glflush;
>    end Render_Scene;
>end Simple_Procs;
>
>
>
>