Page 3 of 3

Re: X and Y

Posted: Sat Oct 26, 2019 5:48 am
by Crayon21
is there an equivalent command for the zx81?

Re: X and Y

Posted: Sat Oct 26, 2019 6:10 am
by XavSnap
… On the Zx81 Basic ?
No…

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

Re: X and Y

Posted: Sat Oct 26, 2019 8:07 pm
by Crayon21
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?

Re: X and Y

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

Re: X and Y

Posted: Sun Nov 10, 2019 4:55 am
by Crayon21
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

Re: X and Y

Posted: Sun Nov 10, 2019 9:52 am
by dr beep
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.

Re: X and Y

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

Re: X and Y

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