Knights Province cover
Knights Province screenshot
Genre: Real Time Strategy (RTS), Strategy

Knights Province

Adding fences

Fences have been long on the game’s todo list. Being a really neat feature described by a single word, it comes with a lot of problems to solve. How does one approaches a feature like that?



First the “wants” had to be outlined. Fences might have a number of variants and uses in the game:

  • Short crossable fences can be used to designate grain fields and orchards. Purely aesthetic
  • Medium breakable fences. Can be a weak fortification, slowing down enemy advance. Maybe they can also be used to keep the cattle
  • Tall tough fences can be a better fortification. More expensive and harder to break
  • If we think about it, fences around house building sites are somewhat related too


Next comes the problems and features exploration phase. Here’s a short FAQ I did on fences before starting the work. Each line poses a problem and has a solution below. The FAQ is not final and solutions can be changed to accommodate for unforeseen problems, but for now I’m quite happy to have most of the questions answered:

  • How are fence plans placed
    - New plan type. Placed between tiles. One side must be walkable/reachable. Cursor magnets to nearest edge and outlines it.
  • How fences get built
    - By builder. He arrives on adjacent tile, digs for a while, waits for timber and hammers the fence in place
  • What do fences cost
    - At least one wood or stone
  • On which side of the fence should the builder remain?
    - Let the fence plan direct from which side it gets built
  • Do builders walk through fences?
    - Maybe they don’t. Let the player manage the sides from which to build.
    - We could allow Builders to walk through fences. But this would break all the immersion and logic. Unless we show Builder hits a fence several times to remove it, walks though and then builds it back again? Builders do walk through small house plan fences though..
  • How fences get demolished?
    - Instantly in a puff of dust
  • How fences get destroyed?
    - Adding hp would be complicated. Let it be just a chance-based instant destruction.
    - Maybe we can have a breaking animation and fence remainders on the ground?
  • How tough are the fences?
    - We can “roll dice” each hit. Chance of destruction can be linked with warriors attack.
  • How do we discourage extensive fortifications, are they a problem?
    - Likely not. The cost is quite high after all.
  • Whose property fences are?
    - Fences belong to a player (so warriors know whose fences to break and whose to walk around)
  • How do fences interact with houses?
    - Fences should be allowed to make perpendicular contact with houses
    - Fences could be allowed to go alongside house border later on, but likely it ’s not needed
  • How to build fenced area for cattle?
    - To become cattle yard it needs to be enclosed
    - Area can be built by builders
  • What is a yard?
    - Any enclosed area of size 4+ touching the house (e.g. side). Max size is .. ?
  • How do animals appear inside the yard
    - Breeder can bring them from the house
  • How do animals disappear from the yard
    - Breeder takes them out
  • How does Breeder carry the animal?
    - Animal goes by itself on a whistle?
    - Animal gets “follow” order?
    - Animal is taken into hands?
  • What if fence gets broken?
    - Yard becomes ordinary terrain
    - Animals can walk away
  • What if fence gets restored (or is built around existing animals)
    - Area becomes yard again
    - Breeder can access animals in the yard
  • What if player builds several yards
    - If they are accessible by Breeder - he can use them
  • What if there are odd units/animals in the yard
    - They remain there, if they can not escape
  • How do animals breed?
    - Breeder brings them in
  • What do animals eat
    - Grass and grain brought by Breeder
  • How do animals grow?
    - Cows/Horses grow +1 for each grain eaten
    - Sheep remain at the same size and just grow more wool
  • Do we always need fences
    - No, if the area is naturally enclosed it should be fine too

This FAQ covered the player-side of things. Having that done the coding could begin. The code was written in a separate SVN branch to allow for easier comparison of before/after and overall changes made.



There was a number of cross-dependent problems in implementing of the fences. Here are some of the solved ones:

  • Fence edges block diagonal unit passability across a vertice between tiles (just like trees and such). However a fence has 2 endpoints, so code had to be updated to let 1 object block 2 vertices.
  • Fences go along tile edges and thus block unit passability. All the passability/pathfinding methods had to be updated to check the edges between tiles for passability
  • Unlike roads and fields, fences need to be built from specified side. Fence plan list had to account for that.
  • Enemy fences should be breakable, so the passability for warriors had to “ignore” the fences and still plan paths through them, knowing that warrior will break the fence on approach.
  • Breaking enemy fences should not interrupt current warriors order
  • Warriors should not break allied fences. Which means the terrain traversability now had to account for player alliances.
  • Breaking a fence should take some time (1-3 hits depending on warriors strength). Had to come up with a simpler formula for that
  • There needs to be support for different fences (visually and mechanically) at least for mapmakers. Thus the fences are planned to have properties and types.
  • Had added dynamic script commands to add or remove a fence.
  • Fences had to have player color markings on them. Since terrain render is already overly complex and overlay render caused some Z-fighting bugs, fences had to be made to render via a different approach that allowed for colors.
  • Refactorings had to be made along the way to adjoin similar methods encountered throughout the code.




Remaining problems and features:

  • Own fences need to be demolishable. There’s still no support for that yet. Not sure if this should be done with a confirmation or not.
  • It would be nice to have own and allied fence lines to be permeable without destruction. Should the gates be added, and if yes - that’s another bunch of problems to solve
  • It would be nice to have fence breaking animation
  • Cattle yards are a whole new can of worms. They will likely be implemented as a separate feature after the fences development is complete.

Fences are available since Alpha r8455. There’s already been some testing going on and a small bunch of bugs fixed.

Campaign improvements

Campaign menu is one of the menus that received the least attention during Alpha development so far. Why is that? Well, it’s not as important as the main game or map editor - it’s rarely used and serves a small role of allowing to click “Start mission” or choose to replay the previously beaten mission. It lagged so much behind now that it’s subpar even by Alpha standards. By requests from mapmakers it’s finally getting some dev time. Along with that campaigns are also getting some new features (campaign scripting, yay!)

What campaign menu should look like? The big idea is to have it in 3D as a sort of map laid on the table, with heights and 3D banners.

However this is far from priority, since it’s better to have a more developed game, rather than campaign menu, right? So for now, campaigns are getting most of their planned mechanics, but still retain its simpler (and easier to develop) menu.



Following features and customization abilities have been added already:

  • Chapters. Each chapter has its own background graphic and subset of missions.
  • Customizable mission flags. Each flag has 3 states that can have custom graphics - locked/normal/won. For example now you can denote fighting only missions with crossed swords and normal missions with city icon.
  • Nodes between flags
  • All these custom graphics can be png files in the campaign folder. If not supplied - the game will use default stand-in images.


New campaign format is mostly self-explanatory (just open the info.xml in a text editor). Images and texts are now referenced from within the campaign spec (info.xml) - less hardcode rules, more customization.

For the technical side - campaigns got scripting support! It’s made of two parts:

  • Persistent data storage between missions. Now mapmakers can record data from one mission and use it in the other. Did you help that rebels town in mission 2 - now rebels can send reinforcements in mission 4!
  • Campaign scripting. Mapmakers get control over which missions get unlocked and when. Did you choose to side-track to the mountains to help the miners or to chase the bandits and let the miners take the usurpers side?


There’s also another neat addition - Campaign Builder - a tool to create and edit campaigns for the game. From now on it will be included in the pack. The tool is rather basic in its look and function, as it’s not the main dev focus. Still it’s handy to set up the template for the campaign and especially the flags/nodes placement.

Give it a try!

  • If you are a player - check it out and report bugs/feature requests
  • If you are a mapmaker - start creating your campaign! (and report bugs/feature requests too)