My original plan was to create an z80 assembler version of Moon Lander. But with the trailer release for the next Matrix movie, I found myself revisiting another program. Built entirely in machine language, Z80 Digital Rain expands on my previous version with a splash of color. Let’s dive deeper.
Last month, I shared an old moon landing program I wrote back in the early 80s. Right after that, I decided to give it a bit of a face lift, updating the visuals without changing the game play. Moon Lander v2 is my updated game, yet still the same BASIC code under hood.
When I first started programming, one of the games we would play on the old teletype machines was a simple moon lander game. The premise is you would use your thrusters to softly land on the moon. Moon Lander was my take of that program a few years later.
As a young teenager, I often wrote programs that I would integrate into other play. In this case, I had probably watched War Games again. The idea of a computer talking to you made for some fun fantasy play. Comp Control a little pretend play where my lowly ZX81 mimicked a much more sophisticated world. I’m sure I was running around my room thinking up some crazy way to save the world.
I was hoping to have finished Gem Quest by now, but May didn’t afford much time. With Summer arriving and the pandemic seeming to be winding down, at least in Boise, my attention is elsewhere. With a short list of ideas, I decided to play off last month's theme. Picture in Motion isn’t new, but it is more interesting to watch.
When Simeon Dwyer shared his machine language line drawing routine, I immediately thought of redoing “The Picture.” Most of my z80 assembly has been with my Gem Quest game. I decided it would be a nice diversion to work on something else, even if a quick one. Picture Asm is the result of that diversion.
I’ve talked about ZX-Ultima before. It was first attempt at building an Ultima like game on the ZX81 using BASIC. Written in 2012, it was a pretty ambitious project for me. I really enjoyed playing Ultima III on my C64 as a teenager. I always wondered what it would look like on my ZX81. It was bad. Yet, at the same time you could see the seeds of what would come later.
If you’ve been following me the last couple of months, you know I’ve been revisiting Gem Quest. Intended to be an Ultima style game for the ZX81, outside of a few demo’s I really hadn’t gotten far. That isn’t the case now. I’ve spent the last month learning z80 assembly code and hacking my way through the game. Tracking my progress, I’ve been capturing that journey in pictures and movies, which I’ve uploaded into a Flickr album.
After sharing Tiles, I started to dig into my previous attempts at building an adventure game. Digging through my past research, I thought about encoding the world differently. Sadly, my experiments using MCODER failed. This spurred me to try assembler again and, to my surprise, build a good start to my game. But first, a trip down memory lane and review my first attempt at building Gem Quest.
In 2012 I wanted to see if I could make an Ultima style game on the ZX81. I had an ambitious plan centered on the tile based graphics. After a few months of testing, I was able to create a working prototype called Tiles. Although the game isn’t done, the idea behind it shows promise. You can move around the map using the standard ASDW movements. Other commands are placeholders for what could be. This article explores how Tiles came to be.
As 2020 wound down, I had a couple of different ideas for new ZX81 programs. Most of them were graphic programs of various sorts. Themes ranged from dumpster fire pictures, an advent calendar, a virus action game, to a solo RPG. Although they were all great ideas, I didn’t think I’d get any complete enough to publish. In the end, I decided to enter in one of my old graphic programs of the Ocean Pacific logo.
As usual, I procrastinated a bit in finishing my ZX81 program for November. Between holidays, work, and NaNoWriMo, I didn’t get around to it until this last weekend. I decided to try something a little different for this month’s program. The program itself, Charts, is a simple line graph plotter—spelling and bugs galore. As interesting as that program is, the real story is how I entered it.
Back in July, I made a mistake and entered in Star Probe again. I had forgotten that I’d already shared it. But, unlike my first attempt, I had taken a different approach which made it a much different game. Jumping ahead, I decided to finish what I started. Here is Star Probe Redo, an updated version as October’s program.
September proved to be a rather busy month, at work and home. It isn’t unusual for me, and I usually find time to throw a render or program together. As this month closed, I found myself in need of a program to share and not a lot of time. While cleaning up a few things on my laptop, I found this little test program I wrote last month that fit the need.
Back in the day I learned to program on school PDP-11 with a 6 teletypes and a CRT attached. I was still in computer club at the time, thinking the 8" floppies were pretty cool. To my despair, the poor thing died that Summer and, when I took my programming class, it was on an Atari 800. But the programs I wrote the previous year stuck with me. Printer Car harkens back to those days.
Lately, I’ve been reflecting on my programming journey. It is hard to believe that it has been over nine years since I started writing my monthly articles. I’m nearing the end of my printouts, and thought I’d write about my ZX81 Dice Game.
Having a healthy imagination and perchance for sci-fi, Spaceship is a bit of both. I assume I conjured up the idea as part of some playtime activity. Written in 1983, it was one of my earlier programs and lacked graphics. Yet, it was still a bit of fun.
I have some sort of fascination with code breaking. A byproduct of all the spy movies I watched as a kid. A friend of my would make spy cases with Lego’s, and I had to build my own of course. I had a wallet with home made credentials and so on. Code Searcher is a bit of a homage to those golden age gadgets of the 60s and 70s.
When I was a child, I remember going over to a friends house and playing Wizardry on his Apple. Leaving his house, I was super excited about the game I saw. Although my lowly ZX81 was no match, I had visions of creating my own games like it. My attempt, although a test, could have been so much more.
A bit cliche by 1985, but I was obviously still playing Frogger and the clones it spawned. With all its dodging and moving, the game is classic for good reason. Even in modern times, it has spawned the likes of Crossy Road and other in spirt games. My own attempt, called Sea Cross, finds you trying to get your family safely across the water and home. I doubt you’ll be able to.
The ZX81’s graphics be a lot of fun to program. Although I wasn’t a big fan of the PLOT command, I do have some examples of its use. My taken on the TS logo for the rock band Twisted Sister is one one example. Like a primitive screen saver, it can be fun to watch.
Okay, I’ll admit that I was a Star Trek junky. As a kid, I remember eagerly waiting each week to watch reruns of the original series with my family. When 1983 rolled around, I’d watched both of the original movies and owned the comic books that bridged the two. As such, creating a Star Trek game on my ZX81 should come as no surprise.
Running platform games with simple controls were all the rage when mobile gaming got started. Although the themes varied, they all tended to have a few if only on control to them. Some made you press down and release. Others ran on their own, requiring you to press or swipe as needed. My journey into the genre began in 1985 when I wrote Bolder. It may not be popular or exciting, but does show that the concept had roots going deeper than you may realize.
For November, I found another missile defense game that I wrote a few years back. I honestly didn’t remember this one until I started to play it. Starting off a bit slow, I kept telling myself that it should speed up. And, it did! Guess, my memory isn’t that bad after all. Let’s dig into Laser Catch a bit more.
Fall weather brings colder weather, colorful trees, and Halloween! The original movie was still a classic in 1984, even if a few sequels had been released by the time I wrote this program. Lacking the chills of the movie, my Halloween tries to convey the futility of running. Michael always wins.