My first computer was a ZX81, and the first game I wrote was called "Frogging", where you have to catch a frog on a lily pad that you can move left or right.
Try it in a browser. Type type R followed by ENTER, and use the 5 and 8 keys to move left and right.
It's not the best game ever, but it's the first program I ever wrote (age 9), so it's not surprising!
The programs are saved in text format with a .bas file extension. Graphics characters and inverse video characters are represented using the conventions described in ZXText2P. The sequence \::, for example, represents a black square.
The zxtext2p command was used to convert these text files to ZX81 P files suitable for use in an emulator, or a real ZX81. I used a modified version of ZXText2P that collapses the display file, so it will fit on a 1K ZX81.
The emulator in web uses the code for JtyOne Online ZX81 Emulator, as modified by www.perfectlynormalsite.com/helloworld.html.
I made a small change so it can load .p files, although it expects the .hex version. The full build is achieved with:
zxtext2p -d -o frogging-reconstruction.p frogging-reconstruction.bas
xxd -p frogging-reconstruction.p | tr -d '\n' > web/images/frogging.p.hexTo try out locally, start a webserver:
(cd web; python -m http.server 8000)and go to http://localhost:8000/frogging.html.
Type R followed by ENTER to run the program, and use the 5 and 8 keys to move left and right.
You can also run the .p file in an emulator, for example using zxsp.