01 · The theatres
Five maps of 16 by 16 squares
Each theatre has its own terrain file, W3.TN, W3.SE, W3.CA, W3.ME or W3.WE. Three of them also bring a map font of their own.
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The flight's own map routine, draw_map, at address $9685 (a number written with a $ is in hexadecimal, base 16), run on the site's copy of the C64's processor with each theatre's map, font, colours and units in place. The site's model of the video chip then draws the screen, with the chip's settings from a frame of the big map recorded in the emulator, the program that plays the part of a C64. The theatre's bytes come from the game's own loads in the emulator, read when the cockpit first appeared on a mission there. "Every unit" marks every unit as seen (bit 4 of its type byte, at $5300 on) before drawing. The map's sprites, the small movable pictures for the waypoint's cross and the helicopter's mark, are left out.
The map has 16 by 16 squares. In all five files the outer two rings of squares are terrain 0, and the big map shows the 12 by 12 inside them. Each square is one byte, the number of one of 33 terrains. The map is drawn in characters, as text is, and each terrain is six characters of the font from character 58 on, three across and two down. The terrains differ from theatre to theatre: the files for training in the USA and for Western Europe share a font, and the other three each have their own.
Each unit is drawn as one character in its square. A unit's kind is a number from 0 to 15 in bits 0-3 of its type byte, and its character is 32 plus its kind, except that an enemy of kind 6 borrows kind 12's character. Friendly units are white, targets purple and the other enemies red. A unit of kind 0 is never drawn: in these files only friendly units have it, 21 of them in Southeast Asia and 2 in Central America. On a mission the map shows a unit only after the helicopter has seen it.