Automap



The automap is a map displayed when the user presses the tab key. As all levels in Doom are flat when viewed from above, generation of such a map is a relatively easy task (as compared to later games which had true 3D engines, thus making it difficult to render a map automatically).

The map shows all segs (segments of wall) the player has seen since entering the level. Therefore, while it is possible to walk around in automap mode, the map itself will not update: the lines shown in the map are marked by the rendering process, which does not occur while the automap is turned on.

The lines in the automap are color-coded. Red lines indicate solid walls. Yellow lines indicate changes in ceiling height (e.g. doors). Brown lines indicate changes in floor height. Light gray lines indicate areas which have not yet been visited (made visible by the computer map powerup). This color scheme may vary depending on the source port being used.

As the Doom instruction manual notes, playing in automap mode is a dubious long-term strategy, since monsters cannot be seen. Certain source ports circumvent this issue by including the automap in a heads-up display.

Keys
Several keys perform actions inside the automap:


 * F: Toggles follow mode. If follow mode is on, the map remains centered on the player, and if not, it is possible to browse the map freely using the arrow keys while the player remains stationary.
 * M: Marks the current position with a number. Up to ten markers may be placed, numbered 0 through 9; further uses of the M key will cause the existing set of numbers to be sequentially erased in favor of the new positions. (In Doom95, this function is extremely buggy and may even cause the program to crash.)
 * C: Clears all marked positions.
 * G: Toggles grid on/off.
 * +: Zooms in.
 * -: Zooms out.
 * 0: Zooms out fully. If pressed a second time without leaving automap mode, returns the map to its previous scale.
 * Tab: Exits automap and returns to normal view.

If one of these keys has also been mapped to a gameplay function (e.g. firing or running), the above table overrides that key's default behavior during automap mode. All other keys can be used as normal, however.

Editing
During the design of a level, linedefs can be flagged by the author so as not to appear on the automap even if the computer map powerup is obtained. However, the iddt cheat code will display all lines.

To avoid giving away secrets, concealed doors can also be marked so as to initially appear red on the map, as though they were solid walls.

Trivia
The iddt cheat code can be used to display all items on the map. Zooming in closely on the player while this is active shows the letters "ddt", a reference to Dave Taylor who wrote the automap code.

Boom modifies this: the letters "jff" are visible instead, a reference to Jim Flynn.