====== Line Type (XG, DED) ======

A //Line Type// defines the behavior of a [[modding:line|map line]], i.e., a wall in the map. 

Line behaviors are implemented by various [[xg:class|XG classes]] that define what the line does. The class's behavior is carried out when the line is [[xg:line_activation|activated]], [[xg:line_activation|deactivated]] (or both) or when some other triggering condition occurs. Some examples of line classes include [[xg:class:plane_move|Move Plane]], [[xg:class:end_level|End Level]], and [[xg:class:wall_texture|Change Wall Texture]].

Line types are a fundamental building block of XG. Please see the [[xg:reference_guide|XG reference guide]] for more information about how to use line types.

===== Example =====

An XG Line Type definition begins like this:

<code>Line Type {
  ID = 5000;  # A unique ID number.
</code>

This unique ID number is required for each line type. It is the actual type number that will be used in a level editor, instead of the line types defined by the original game.

===== About XG lines =====

An //XG line// is a normal Doom line whose type is set to an //XG line type//. XG lines can either be //active// or //inactive//. It is possible to //disable// an XG line, which means the line will be skipped in all event processing and the line's timer will not be incremented.