Sinclair ZX80 / ZX81 / Z88 Forums

Hardware required...

ZX81 with ZXPand+UDG4ZXP in CHR$128 mode or
ZX81 with ZXPand+Chroma in CHR$128 mode or
ZX81 with ZXPand+CHR$128 board
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CHR$128 Mode

CHR$128 mode uses bit 0 of the I register to select between two tables of de-
finitions. This allows redefinition of all 128 displayable characters. When
bit 0 of the I register is 0 then CHR$128 mode only allows the basic 64 charac-
ters to be redefined, and when bit 0 is 1 then all 128 characters can be rede-
fined.

The "C" Option - Convert CHR$128 to CHR$64

Standard ZX81 programs expect the character set to consist of only uppercase,
standard and inverted characters. This option converts a CHR$128 font to that
format (CHR$64) for use with a standard ZX81 program.

Demo videos...

https://m.youtube.com/watch?v=4DtMOV_Nt3Y

https://m.youtube.com/watch?v=b0Kga_JJR7Q

Have Fun;

Greg

Most excellent Greg, just the kind of thing that floats my boat as Iv'e posted quite a few UDG conversions over time and this will come in most useful.
I noticed from the video that you too have also done a UDG version of Tut-Tut which I have to say is better than my effort

Some good ideas for me to work with so thanks a million for sharing, Greg.

The amulet and bracelet ought to look familiar. I'll be posting a redefine UDGs app shortly.

GCHarder wrote: ↑Wed Sep 20, 2023 10:21 pm The amulet and bracelet ought to look familiar. I'll be posting a redefine UDGs app shortly.

Indeed they do, they look just like the ones I designed!

Can't wait to see the UDG re-definer.

The games get way cooler with a font replacement !
I really like those retrofits improving an original program leaving the original code untouched (the CHROMA interface really brought it to the extreme),

Some year ago I introduced an "SVG vector graphics" capture option on the FUSE emulator: you first run a program in BASIC drawing a picture, then the vector output can be stretched without pixelating. The zx81 resolution is probably too low for interesting results, though.

Yes the fonts look great and it would be nice if the graphic characters can be altered too with the program Greg is coming up with.
At the moment I'm using Andy Rea's UDG designer which does the job really well but always welcome more tools in the box, really looking forward to this.

Demo video...

https://m.youtube.com/watch?v=PGGrPzcxgVE

Thanks, that is an exellent demo!