28/08/2007 @07:17:20 ^09:26:49


All this messing with NetHack and I almost forgot it's 10 years since the day I got my first copy of Doom (well, Doom 2) today.

For some unrelated reason I'd taken my computer to the house of a guy I knew at primary school, who'd in 1995 showed me the game, which I suppose was at the height of its popularity. I remembered he had a level editor for it as well, and as I was in the summer between A-levels and university, looking for shit to do, and by 1997 I had a computer that could run DOS stuff under "emulation".

Of course after about a week, only having played through the first 8 levels, I managed to corrupt the IWAD. Don't ask me how. I ran a program and it turned out to be broken. Anyway it took a few months to get another copy.

I didn't get chance to play it again until Christmas. I slowly played through, one level at a time, eventually finishing it. I also followed it up with a godmode run on the hardest skill level, just so I could see it with the full numbers of monsters in. All this was finished by early January 1998, whereupon I said, yeah, that was all right, but whatever, let's do something else now.


One night in March 1998, while on one of my infrequent trips as a dropout to the university computer lab, I found a copy of a program called DeHackEd. This allowed you to mess around with the game's internals by editing the actual executable file. I also found the UDS, an inspirational document which described much of these internals, and the map format. At that point Doom went from being a game I could play, to a game I could play with.*

I made the lesser spotted marauding barrel, which shuffled round the map, snuck up on you and exploded. I sped the guns up slightly and could play the game on Ultra-Violence skill without having to use god mode. I recall realising, after about a month, that I wasn't doing much else with the computer besides Doom stuff. All other projects were being neglected. I'd become obsessed.

* Needless to say the level editing thing hadn't worked out. The editor was a pile of shit. I still haven't found a map editor I don't hate.


After this I started doing all kinds of experiments to find out limits and properties of the game. The range of a bullet, the range of the BFG cone effect, the range of autoaim, relationship between the dehacked variable "missile damage" and the amount of damage done**, relationship between monster hit points and the player's health, and so on.

I also worked out much of the format of a saved game file. I could fire a BFG shot across a room, save the game, and hack it so the BFG shot was dark red and travelling so slowly you could hardly see it move.

The stupid part here was that, by then, the source was available, so all my work was pointless. However, I didn't know this, and being away from university and the internet I had no way of finding out.

** I remember being disappointed to realise that there's no real difference between an imp's fireball and a baron's nukage-throwing other than the amount of damage it does.


I finally acquired the original Doom and its ill-fitting fourth episode in July 1998. This convinced me to stop using the sped-up weapons patch, as it relied on stuff in the Doom 2 IWAD and caused Doom to crash. Also, as I found out, Doom is easier than Doom 2, and I could do without it (although, some of episode 4...)

As we move through the rest of 1998, and into 1999, the PWADs and source ports eras began. That's a whole other thing so this is a good place to stop.