Re: [gl4java-usergroup] OpenGL Extensions

[<jen...@ag...>]

Hi Pepijn, hi ng,

i'm followed your discussions about extending gl4java to the future since
i'm using gl4java now for more than a year.

The extension mechanism you've described should be the right way. Anyway
maybe it makes sense to not redefine
the init(...)-methods because as you know there is a difference in the
init()-methods coming from the subclassing model and the GLEventListener
model.
in GLCanvas: init() just without arguments
in GLEventListener: init(GLDrawable)

What you think about something like this:
preGLinit()    -- former preInit() in GLCanvas
postGLinit(GLContext)    -- for the extension instanciation you've described

GLCanvas.init()/GLEventListener.init(GLDrawable) left untouched for backward
compatibility

regards,
Jens


----- Original Message -----
From: "Pepijn Van Eeckhoudt" <pep...@lu...>
To: <gl4...@li...>
Sent: Sunday, May 11, 2003 12:09 PM
Subject: [gl4java-usergroup] OpenGL Extensions


> I've been trying to come up with a clean mechanism to handle extensions
> in OpenGL. The current solution is to throw all methods and tokens
> (core OpenGL and extensions) into one big class. This leaves you with a
> class that has many methods that simply do nothing. I'm hoping we can
> do better than this.
> The best solution I've been able to come up with is the following:
> - We keep the GLFunc class but it only contains the core OpenGL
> functions and tokens
> - For each extension we provide a class that contais the necessary
> methods and tokens. This extension class can then be loaded if a user
> needs it. I've made a dummy example for the vertex program extension
> (not 100% correct, but it's a good illustration.
> If this is the way to go it might be a good idea to do the same loading
> type mechanism for the core functions as well, for consistency's sake.
> You're application would then be responsible for creating an instance
> of GL, GLU, and any other extension objects and maintaining them. This
> would have to be done in the init method, because the GLContext object
> must already have been created.
>
> Example:
> private GL gl;
> private GLU glu;
> private ARBVertexProgram vertProg;
>
> public void init(GLDrawable gld) {
> GLContext context = gld.getContext();
> gl = GL.createNewInstance(context);
> glu = GLU.createNewInstance(context);
> vertProg = ARBVertexProgram.loadExtension(context);
> }
>
> I would love to here some other ideas and feedback about this.
>
> Pepijn
>
> P.S. Maybe we should move our development discussions to the devel
> list...
> Alex: sorry I ended up playing Metroid Prime all night. Damn Nintendo :)
>