Friday, 7 June 2013

The Making of Ant Attack!

Someone sent me this clip and wow, what memories came flooding back.

Ant Attack on the ZX Spectrum was the first computer game that not only totally hooked me, but made me think "I wanna be able to do that". At one point, circa 1984, I could even beat the "hall of fame" high scores published in Personal Computer Games (PCG) magazine, though I was much too shy to write in about it.

One of the dubious joys of the Spectrum was getting to actually hear programs loading. Games could take upwards of 20 minutes to load from cassette tape - which meant you made damn sure you made the effort to enjoy them - and as they loaded you could hear the whistles, chirps and drones of the bits and bytes of game code.

Every game had its signature loading sound and I can still immediately recall the last few clicky seconds of Ant Attacks loading before it launched into the beepy tune that accompanied the blocky title screen.

Ant Attack was my first hacking experience. I worked out how to break into the tape loader and get access to the BASIC program that controlled the machine code routines, then I started messing with it to move things about about, such as the characters you're supposed to rescue (the positions were all coded in DATA statements in the BASIC code)

I moved on to searching through the programs memory image, looking for the data for the "city" that was the game area, then printing it out in long strips on my Alphacom 32 toilet roll printer and sellotaping them together into a map which I proudly blu-tacked to my bedroom wall.

Some 10 years later I created my own version of the game for the PC, written in C and inspired by a superb Manic Miner port. I found a cassette tape image file for Ant Attack somewhere on the early internet and tracked down and pulled out the bitmaps for the game graphics and the city map. I got the movement and display routines all working but unfortunately didn't get the game play finished off :-(

Anyway it was a joy for me to see this interview with Sandy White, the creator of Ant Attack. i had no idea what he even looked like before seeing this, and I only remember his name from the big "(C) SW" laid out in bricks on the city map in the game, which I remember noticing when I printed out the map.

I was pleased to see Sandy White HAND ASSEMBLED all the machine code for the game.. now this really does bring back memories as I used to do this myself, on a much simpler scale, armed only with the list of Z80 assembly language instructions that were printed alongside the character set at the back of the ZX Spectrum manual. Top stuff! Hey I even used to hand assemble Z80 machine code without a reference list, just by remembering all those opcodes from looking them up so many times. I really should have got out more.