hobbit-text-game

The Oregon Trail, 1985

MECC’s The Oregon Trail for the Apple II (1985, version 1.4) as one self-contained page, oregon85.html, that works on a phone. It is a port, not an emulator: the game’s Applesoft BASIC was translated program by program, so every price, probability, formula and message is the original’s, and the disks’ own pictures, sprites and tunes are drawn and played the way an Apple II showed them. The numbered questions are buttons; the hunting and rafting screens take touch as well as keys; the journey is kept in the browser so a reload carries on where it was, and the Oregon Top Ten and the tombstones you leave persist between games.

What is in the port

• MENU / BUY SUPPLIES — occupation (banker, carpenter, farmer), the party’s names, the departure month, Matt’s General Store.
• OREGON TRAIL — the day-by-day travel with its weather tables (six stretches of trail, twelve months), the health score fed by temperature, clothing, rations, pace, fatigue and illness, the fifteen kinds of mishap with their exact odds, the eighteen landmarks and two forks, the fort stores with rising prices, trading, resting, the map, and the people to talk to at each landmark.
• RIVER.LIB / CROSS.LIB — the four crossings: fording, caulking, the ferry, the Shoshoni guide, waiting; depths and widths that follow the rain.
• PART, LF, TOMB, END — broken wagon parts, fires, thieves, abandoned wagons, deaths and epitaphs, the Barlow Road.
• The hunt — rebuilt from the machine code the game keeps in the language card (the & HUNT command): six animals with their sizes, speeds and meat, the obstacles that grow in each region, the eight-direction hunter, bullets that fly until they hit something, and the 2,500-turn clock.
• FLOAT — rafting the Columbia, line for line.
• WIN — the points, the occupation multiplier, the ratings and the Top Ten.

Files

File	What it is
oregon85_src.html	the page: markup, styles and the interface script
js/engine.js	the Apple II side: hi-res screen, decoders, sprite blits, colour rules, tunes
js/game.js	the game, transliterated from the BASIC (line numbers in the comments)
js/hunt.js	the hunting screen
js/raft.js	the Columbia
build.py	inlines the scripts and data.json into oregon85.html
tools/pack.py	makes data.json from apple2/: pictures, image libraries, tunes, the variable table, the talk texts
tools/pck.py, tools/ima.py	decode the picture and image formats to PNG
apple2/	the files from the disks the page uses
src/	the Applesoft listings the port follows

Notes on the formats

A .PCK is one 280×192 hi-res screen, run-length coded column by column. An .IMA library is a count, an offset per image (bit 15 marks a raw image), then each image as a width in 7-pixel bytes, a height, and its bytes — row by row for raw images, column by column and coded like the screens otherwise. VAR.BIN is the game’s saved Applesoft variable table (landmarks, distances, rivers, weather codes, prices). MS*.BIN are the landmark tunes: pairs of note and duration.

Credits and rights

• The Oregon Trail is © MECC (the Minnesota Educational Computing Consortium); the program, pictures, sprites, texts and tunes are theirs.
• The page and the tools are released under the MIT licence.

This site is open source. Improve this page.