From: Marcus Sundberg <mackan@stacken.kth.se>
  To  : ggi-develop@eskimo.com
  Date: Tue, 25 Aug 1998 00:08:34 +0200

Re: Video memory.

teunis wrote:
> 
> On Sat, 22 Aug 1998, Marcus Sundberg wrote:
> 
> > > I definately _don't_ want to open a whole GGI visual or any other heavey
> > > object for each such sprite,
> > > (since I have hundreds of them).
> >
> > As I wrote in another post:
> > Requesting auxiliary buffers (offscreen pixmapstorage, z-buffers,
> > sprite buffers or whatever) should be in an (or more than one probably,
> > given the number of different buffertypes) extension, and these
> > extensions would naturally have functions to do every possible
> > operation on these buffers, such as blitting them to the screen.
> 
> Enough of saying where it should be!
> 
> Please I need some help here!  How should it *look*?!?!?!?!
> [unless I have a buncha notes in front of me I don't know]
> .... I know!  Unless someone says otherwise, I'll copy OpenGL :)
> [support Z-buffers, W-buffers, bitmaps, bitmapsets (1.2) :]
> or should it be display-Z-buffer; display-W-buffer; display-bitmap
> (support >1 frame) ?????

_I_ don't know! I have never used Z/W buffers, and I haven't
used sprites since the C64 days. ;-)
What I _do_ know is libggi internals, and I can help you with
any technical details regarding libggi and extensions.
But first _please_ just look at the misc extension:
degas/lib/libggi/extensions/misc/init.c
degas/lib/libggi/extensions/misc/stubs.c
degas/lib/libggi/extensions/misc/misc_int.h
degas/lib/libggi/extensions/misc/misc.h
It's a total of less than 150 lines and should be fairly easy
to get the idea.

As for the API, it's you people who know these buffer-types and
their uses, so you have to design it.

> And how should display-targets manage data?

I thought you didn't want to open a whole visual for each
buffer... And this is exactly what a display-target does -
it opens a visual. Once a again - look at the misc-extension
and feel free to ask about anything that's unclear.

//Marcus
-- 
-------------------------------+------------------------------------
        Marcus Sundberg        | http://www.stacken.kth.se/~mackan
 Royal Institute of Technology |       Phone: +46 707 295404
       Stockholm, Sweden       |   E-Mail: mackan@stacken.kth.se