From: Andrew Apted <ajapted@netspace.net.au>
  To  : ggi-develop@eskimo.com
  Date: Mon, 10 Aug 1998 22:58:59 +1000

Re: Big changes to CVS tree

Marcus writes:

>  * Removed ggi_visual->priv and replaced it with
>    void		*targetpriv;	/* Target private data */
>    void		*helperpriv;	/* Helper private data */
>    void		*genericpriv;	/* Generic library private data */
>    void		*hwdrvpriv;	/* HW-driver private data */

Do the "generic-linear-*" libraries use the "hwdrvpriv" one ?
And what is genericpriv, is it just for "generic-stubs" ?

I'm also left wondering about things like "generic-ramdac" and
"generic-ioctl".  Perhaps this can be integrated with ggiGetAPI(), e.g.
a library with number #N can store it's private data in vis->priv[N] ?
Hmmm, each library wouldn't know what #N it was though...  Bummer.

>  * Removed LIBGGI_FB_LINEAR, added LIBGGI_CURREAD and LIBGGI_CURWRITE
>    and made the default libs use those.

There is a problem with the app/priv separation.  For trueemu (and
others), I want to load and use "generic-linear-*" libraries to do the
actual drawing, but I also want the direct-buffers for each frame to be
private.  Currently we have something like :

   #define LIBGGI_CURWRITE(vis)  (LIBGGI_APPBUFS(vis)[curframe]->write)

which would mean the buffers are always public.  In light of this, I
think we should have just a single db array, where the first M buffers
correspond to each frame (0 .. M-1), and an extra flag like
GGI_DB_PRIVATE which causes those buffers to be skipped by the
ggiDBGetNumBuffers() and ggiDBGetBuffer() functions.

Another thing...  so we can implement ggiSetDisplayFrame(),
ggiSetReadFrame() and ggiSetWriteFrame(), we need three values instead
of just "int curframe" in ggi_visual.  We could have :

    ggi_directbuffer *d_frame;   /* current display frame */
    ggi_directbuffer *r_frame;   /* current read frame */
    ggi_directbuffer *w_frame;   /* current write frame */

And thus :

    #define LIBGGI_CURREAD(vis)   (vis->r_frame->read)
    #define LIBGGI_CURWRITE(vis)  (vis->w_frame->write)

How does this sound ?  [I'm happy to implement all this].

Cheers,
_____________________________________________  ____
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  Andrew Apted   <andrew@ggi-project.org>       \/