====== XG sector lighting examples ======


A [[xg:sector_type|XG sector type]] can be used to define different colored lights/tints within a sector.


===== About XG value functions =====


To begin with this will look somewhat complicated until you learn what the various symbols in a [[xg:function_script|function script]] mean (these symbols and more are described in detail on the [[xg:sector_type|Sector Types]] page).

We suggest you start off with the simpler stuff (such as the //Bright Green// example further down) and then move on from there.

The basic concept is that all sector lighting effects are NOT static even if they appear to be. For example even a sector with a non-animated blue tint is infact animated but the user doesn't see this animation. From the engines point of view it is animating //blue → blue → blue...// all the user sees is //blue//.

The animation of the light is described using what is called a //function// - a series of symbols which are interpreted by the engine one by one like a script, except that **only one symbol is interpreted per tic**.


===== Bright green =====


This will give the sector a green tint which is defined within (Green fn). You can mix and match (Red, Green and Blue fn) for mixed colors and results.

<code>   Sector Type {
     ID = 5010
     Comment = "Green sector light"
     Red fn = "a"
     Green fn = "z"
     Blue fn = "a"
   }
</code>

===== Red, slowly fading in/out =====


This creates a slow fading in/out red light (looped) in sectors with the **9006** special. The Blue function is linked directly to the Green function (Blue fn = "=g") so it is the same as having written "a >az<" for the Blue function.
Both **Green fn min tics** and **Green fn max tics** equal //35// meaning that it takes 35 tics (one second) to do a full cycle (from > to < in the function script) and that no random timing occurs.

<code>   Sector Type { ID = 9006
     Comment = "Slow fading Red light"
     Green fn = "a >az<"
     Green fn min tics = 35
     Green fn max tics = 35
     Blue fn = "=g"
   }
</code>

==== Function script meaning ("a >az<") ====


Begin at //a// (0). Set the loop start postion //>//. Fade to //a// (0). Fade to //z// (255). Set the loop end position //<//. When the script reaches the end loop postion //<// it loops back to the start loop position //>//.


===== Slowly fading: blue → red → yellow =====


This creates a slow fading Blue to Red to Yellow (looped) light in sectors with the **9005** special. It takes 70 tics (two seconds) for each function script to do a full cycle and because the min max values are all the same no randomness occurs.

<code>   Sector Type { ID = 9005
     Comment = "Slow fading Blue > Red > Yellow light"
     Red fn = "a >azz<"
     Red fn min tics = 70
     Red fn max tics = 70
     Green fn = "a >aaz<"
     Green fn min tics = 70
     Green fn max tics = 70
     Blue fn ="a >zaa<"
     Blue fn min tics = 70
     Blue fn max tics = 70
   }
</code>

==== Function script meaning ("a >azz<") ====

Begin at //a// (0). Set the loop start postion //>//. Fade to //a// (0). Fade to //z// (255). Fade to //z// (255). Set the loop end position //<//. When the script reaches the end loop postion //<// it loops back to the start loop position //>//.


===== Randomly flickering yellow light =====

<code>   Sector Type { ID = 9004
     Comment = "Randomly Flickering Yellow light"
     Red fn = "a >tz?32A<"
     Red fn min tics = 70
     Red fn max tics = 70
     Green fn = "m >mz<"
     Green fn min tics = 70
     Green fn max tics = 70
     Blue fn = "=r"
   }
</code>

===== See also =====

  *  [[xg:function_script|XG function script]]