Toni Westbrook dot Com

The Joy of Computer Science and Engineering

Just a quick post, I have most the AJAX functionality done. I need to clean up a few little things like making sure the output window is always scrolled to the bottom, and handling when the page needs to redirect (in the case of game restarts/quits), but otherwise it works well.

Things have been a bit hectic lately – with the massive cooking and cleanup of Thanksgiving, and preparing for the TPUG WoC expo (and driving to and from Toronto to get there), I haven’t had a ton of time to do much coding. I did manage to slip in a couple hours last night and finished up the save/restore code.

It was actually pretty easy – what’s nice about DrupalZM is since it’s being driven from the web, it needs to save the state of the z-machine to the DB every page refresh. The save/restore code simply copies the current state of the machine to a save slot. Specifically, the table that stores the state of the zmachine now has a “slot” field associated with each record. Slot 0 indicates the current state, while slots 1-9 are saved games. Anytime a game is saved, DrupalZM simply copies the record in slot 0 to the desired slot, and restoring does vice versa.

I’m implementing a simple block to allow for easy saving/restoring. Classically one would type “save” or “restore” during gameplay, but typing these commands out in DrupalZM instructs the player to use the functionality in the block. The block will make saving/restoring much faster, plus an added bonus is the screen buffer is completely stored during the save process, so when a user restores a game, it shows them all the text on their screen exactly how it was at the time of saving.

To Do

Most of the zmachine is functional for versions 1-3 of zcode, but the following is still left to do (not necessarily in order of how I’ll tackle it):

1. Debug current issues (picking up “all” items seems to fail, zcharacter->ascii translator is still missing small bits of functionality, out of the 3 games I’ve tried, 2 work but 1 gets caught in an endless loop processing upon issuing the first command)
2. Finish all opcodes for versions 4-8 of the zmachine
3. Implement an AJAX interface
4. Finish the save/restore block
5. Implement room location/moves status bar (as well as exporting this with scores to be used elsewhere on site (e.g. location of currently logged in users, high scores per game, etc)
6. Experiment with extra functionality (quasi-multiplayer, automapping, integrating zmachine objects with drupal nodes/fields)

One more quick update – I figured that if Zork I worked so well all the way up to the Troll room, that I could try giving another Zmachine a whirl and see how far it got. I added a node for “The Lurking Horror”, one of my favorite Infocom games of all time. There was one opcode that it used to manually call for a refresh of the status line that I needed to add, but after that…..

You’ve waited until the last minute again. This time it’s the end of the term, so all the TechNet terminals in the dorm are occupied. So, off you go to the old Comp Center. Too bad it’s the worst storm of the winter (Murphy’s Law, right?), and you practically froze to death slogging over here from the dorm. Not to mention jumping at every shadow, what with all the recent disappearances. Time to find a free machine, get to work, and write that twenty page paper.

THE LURKING HORROR
An Interactive Horror
Copyright (c) 1987 by Infocom, Inc. All rights reserved.
THE LURKING HORROR is a trademark of Infocom, Inc.
Release 203 / Serial number 870506

Terminal Room
This is a large room crammed with computer terminals, small computers, and printers. An exit leads south. Banners, posters, and signs festoon the walls. Most of the tables are covered with waste paper, old pizza boxes, and empty Coke cans. There are usually a lot of people here, but tonight it’s almost deserted.

A really whiz-bang pc is right inside the door.

Nearby is one of those ugly molded plastic chairs.

Sitting at a terminal is a hacker whom you recognize.

>s
Second Floor
This is the second floor of the Computer Center. An elevator and call buttons are on the south side of the hallway. A large, noisy room is to the north. Stairs also lead up and down, for the energetic. To the west a corridor leads into a smaller room.

>w
Kitchen
This is a filthy kitchen. The exit is to the east. On the wall near a counter are a refrigerator and a microwave.

Sitting on the kitchen counter is a package of Funny Bones.

>open fridge
Opening the refrigerator reveals a two liter bottle of Classic Coke and a cardboard carton.

>take coke
Taken.

Worked great!