X and Y

A place to discuss the ZX80's and ZX81's younger brother - the Sinclair ZX Spectrum
Crayon21
Posts: 119
Joined: Sun Nov 04, 2018 2:33 am

Re: X and Y

Post by Crayon21 » Sat Oct 26, 2019 5:48 am

is there an equivalent command for the zx81?
zx81: great yet flawed
Zx spectrum: masterpiece that keeps on giving

(wish it weren't so expensive) :o

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XavSnap
Posts: 762
Joined: Sat May 10, 2008 4:23 pm

Re: X and Y

Post by XavSnap » Sat Oct 26, 2019 6:10 am

… On the Zx81 Basic ?
No…

With a UDG card, just redefine the right characters to display.

Crayon21
Posts: 119
Joined: Sun Nov 04, 2018 2:33 am

Re: X and Y

Post by Crayon21 » Sat Oct 26, 2019 8:07 pm

UDG card? Like an SD? I'm using an emulator not the physical hardware, and even if i could, they're almost $600

anyway, what do i do? what command?
zx81: great yet flawed
Zx spectrum: masterpiece that keeps on giving

(wish it weren't so expensive) :o

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: X and Y

Post by 1024MAK » Sat Oct 26, 2019 10:11 pm

UDG card is an extra PCB that connects to the ZX81. The most common from the time of the ZX81 had various “UDG” in ROM. But the same PCB could have a RAM chip, and then you could design your own UDG. One limitation was that either the extra ROM or the extra RAM based UDG characters completely replaced the standard ROM character set.

The original UDG boards had to be fitted internally to a ZX81. However, the modern designs fit externally.

Mark

Crayon21
Posts: 119
Joined: Sun Nov 04, 2018 2:33 am

Re: X and Y

Post by Crayon21 » Sun Nov 10, 2019 4:55 am

I'm trying to create a pong clone for the zx81. how do i get the graphics to move (I.E Like in 3D monster maze except this is 2D)
? I want to map the up and down keys to W and S or Up and Down respectively. any help would be appreciated. trying to fit in 2k
zx81: great yet flawed
Zx spectrum: masterpiece that keeps on giving

(wish it weren't so expensive) :o

dr beep
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Location: Boxmeer

Re: X and Y

Post by dr beep » Sun Nov 10, 2019 9:52 am

Make the bats with a leading and ending blanc, then you don’t need to erase the bat on movement.
For speed use PRINT AT, also for ball but calculate which graphic is needed (4 possible).
You need to erase the ball before reprinting because it can move to another position.
Do not print ball on the bats but test before it is there and only print it when no bat is there to show a miss.

dr beep
Posts: 1229
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Location: Boxmeer

Re: X and Y

Post by dr beep » Sun Nov 10, 2019 9:54 am

Crayon21 wrote:
Sun Nov 10, 2019 4:55 am
I'm trying to create a pong clone for the zx81. how do i get the graphics to move (I.E Like in 3D monster maze except this is 2D)
? I want to map the up and down keys to W and S or Up and Down respectively. any help would be appreciated. trying to fit in 2k
2K must fit. I did it in 1K and hires.
https://m.youtube.com/watch?v=lbgyXvxuf6U

dr beep
Posts: 1229
Joined: Thu Jun 16, 2011 8:35 am
Location: Boxmeer

Re: X and Y

Post by dr beep » Sun Nov 10, 2019 9:59 am

1024MAK wrote:
Sat Oct 26, 2019 10:11 pm
UDG card is an extra PCB that connects to the ZX81. The most common from the time of the ZX81 had various “UDG” in ROM. But the same PCB could have a RAM chip, and then you could design your own UDG. One limitation was that either the extra ROM or the extra RAM based UDG characters completely replaced the standard ROM character set.

The original UDG boards had to be fitted internally to a ZX81. However, the modern designs fit externally.

Mark
USCII is a tool which allowes you to use UDG in BASIC without special hardware, only a RAM-pack capable of hires.
viewtopic.php?f=6&t=3124&p=33382&hilit=Uscii#p33382

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