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A simple scrolly bouncy demo
Posted: Wed Dec 20, 2017 10:31 pm
by Shaun_B
Here's a little BASIC demo that I wrote while messing about.
[EDIT] Version 1.1 is a bit better again I think.
[EDIT] Version 1.1a is further improved
Happy zXmas!
Thanks,
Shaun.
Re: A simple scrolly bouncy demo
Posted: Thu Dec 21, 2017 7:00 am
by Paul
Thanks for the demo.
It works great in ZedEx on my android phone.
Re: A simple scrolly bouncy demo
Posted: Thu Dec 21, 2017 10:23 am
by Shaun_B
Thanks Paul.
I'm going to see if I can make a reasonable snowfall-type effect with BASIC, but perhaps it is not possible.
Regards,
Shaun.
Re: A simple scrolly bouncy demo
Posted: Thu Dec 21, 2017 11:02 am
by Shaun_B
I've made a slight improvement to the listing; in line 6, the cursor is re-positioned to the start of the line so that when line 3 fires (to clear the scrolly), it's already in the correct place. I think this makes for a slightly better frame rate as well. See below:
- zx81-listing.png (2.11 KiB) Viewed 4463 times
Regards,
Shaun.
Re: A simple scrolly bouncy demo
Posted: Thu Dec 21, 2017 4:07 pm
by Becky
That's really impressive. I would have thought it would be slower than that.
Becky.
Re: A simple scrolly bouncy demo
Posted: Thu Dec 21, 2017 4:37 pm
by sirmorris
I'm pleased that someone's giving the old BASIC ROM some lovin'! Keep it up Shaun
Is there some benefit to PRINTing AT 0+Y rather than just Y? There is a number parse and addition there that you don't have to do or so it seems to me.
Re: A simple scrolly bouncy demo
Posted: Thu Dec 21, 2017 5:23 pm
by Shaun_B
sirmorris wrote: ↑Thu Dec 21, 2017 4:37 pm
I'm pleased that someone's giving the old BASIC ROM some lovin'! Keep it up Shaun
Is there some benefit to PRINTing AT 0+Y rather than just Y? There is a number parse and addition there that you don't have to do or so it seems to me.
No, you're right, dumb mistake! It may be removed to save probably some processor t-states.
Regards,
Shaun