[Coco] Syscall to get the window screen and width

[Jeff Teunissen]

It is possible to gain direct access to the screen memory, but you have to
give up some of your 64K to do it. That's an easy enough tradeoff for a
game which might fit its code and the rest of its memory in 32K.

On Fri, Mar 14, 2025, 16:54 Patrick Ulland via Coco <coco at maltedmedia.com>
wrote:

>
> On 3/8/2025 9:28 AM, plt via Coco wrote:
> > In Basic09 is there a way to find the current window that your using?
> >
> > Thanks
>
> If you are coming from DECB, is this the XY problem starting to gel?
>
>
> Let me ramble a minute. In Microsoft Basic (DECB), everything is flat -
> if you can write it, you can read it back. This includes the video
> display, everything on it and every register that controls it. Example,
> it makes sense to save game state as/on the display to save total
> address space.
>
>
> In OS9, the screen is conceptually output only. It’s RAM is not your
> RAM, yes you can get there at a cost, unless Level 1 forces your hand
> you probably want to make your own screen with dwset or owset and work
> with that. Keep in mind the screen is outside your 64K, it is simply the
> output device/resolution for this run.
>
>
> Once you write things to it, those things are gone. Can’t quickly PEEK a
> pixel color for hit detection, etc. Instead we must use a local fixed
> size array that is inside your 64k. Work in that space, then as output,
> project to that variable sized external screen.
>
>
> It’s worth the trip.
>
> -ricku
>
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