TerrainMaskWML
The [terrain_mask] tag
The [terrain_mask] tag makes map manipulation from within WML much easier. It uses a Wesnoth map as a "mask" over a given location, placing it down on top of the scenario map. Fog('~') and void(' ') are used like alpha in an image; i.e. they cause the previous terrain to be used.
- x,y the x,y location in the scenario map to place the top-left corner of the mask onto
- mask a Wesnoth map; see BuildingMaps.
- [rule] specifies a rule for blending the mask with the scenario.
The terrain on each hex fitting the rule will be changed to the terrain specified in the rule.
- old a list of terrain letters. The rule fits only those hexes that have this terrain in the scenario.
- new a list of terrain letters. The rule fits only those hexes with this terrain specified in the mask.
- terrain the letter of the terrain to change hexes which fit this rule(i.e. for which the new character in
the mask falls on top of the old terrain in the scenario) into.
(SVN terrain only) The rules haven't changed but the letters should be changed to the new letters.
As an example, suppose you want to lay down a road somewhere. You could specify by hand the path the road takes using [terrain], or you could use [terrain_mask]:
[terrain_mask] x,y=12,10 mask=" r~~~~~~~~~ r~~~~~~~~~ ~r~~~~~~~~ ~r~~~~~~~~ r~~~~~~~~~ ~r~~rr~~~~ ~~rrr~rr~~ ~~~~~~r~~~ ~~~~~~rr~~ ~~~~~~rrrr" [/terrain_mask]
For instance, suppose you want snow to fall in an area. You want villages (v) to turn into snowed-villages (V), forest (f) to turn into snowed-forest (F), hills (h) to turn into snowed-hills (H), and grassland (g) and roads (r) to turn into snow (S), while other terrain remains untouched. You could look over your destination map and work out which terrain type is which and draw your mask, but that's alot of effort, you want to just draw a simple mask which has areas of snow and areas of no snow, and make the game work out the rest.
You can do it like this:
[terrain_mask] x,y=1,1 mask=" ~S~~~S~ ~S~S~S~ S~~SSS~ ~SSSSSS ~~SSSSS ~~~SS~~" [rule] old=v new=S terrain=V [/rule] [rule] old=f new=S terrain=F [/rule] [rule] old=h new=S terrain=H [/rule] [rule] old=gr new=S #don't specify terrain and it just uses the new terrain [/rule] #default: Will match everything, since 'old' and 'new' aren't #specified. Set 'use_old=yes' to signal no change. [rule] use_old=yes [/rule] [/terrain_mask]