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.