From The Battle for Wesnoth Wiki
Revision as of 16:09, 31 December 2017 by Mattsc (talk | contribs) (Existing bugs or undesirable features: remove invalid task (function works, wiki documentation is wrong))

We are permanently updating this page. Parts marked by strikeout will likely be deleted shortly.

This page is here to document easy to do coding tasks. It is not here to double the feature request database, and should only be filled by people that know the code well enough to judge the difficulty of a given task.

If you are such a person, you should feel free to edit this page.

If you're not, you should post a feature request and discuss your idea on the forum or IRC. A coder with better knowledge of the code might give you the green light to add your feature here.

Anybody should feel free to add "clues" to any tasks, that is entry points, traps to avoid, person to contact to discuss and so on.

If you plan to work on a feature, write your name at the bottom of the feature, with the date. Note that if you are too long at working on a feature we'll "free" it back (that is if you're not working on it. If you have problems implementing it, just tell us....)

If none of these are to your liking, feel free to check our bug tracker with a broad spectrum of tasks.

Engine related features

Make a "map diff" tool to visualizes changes between two version of a map

Maintainers of maps often make small tweaks for balance purposes. For someone who doesn't know the map like the back of their hand it may be very difficult to spot exactly what changed. There isn't any really good way to do this right now -- using the 'diff' tool at command line doesn't give good results for .map files.

Such a tool would be helpful for someone who maintains a map pool containing maps made by others, also for someone who wants to browse a repository and examine balance changes on several maps, which could be instructive for someone who wants to make and balance their own maps.

There's any number of ways to actually do this, one might be to have a feature in the map editor that takes the name of another map and adds map labels to indicate what hexes changed. It could also be a command accessible in debug mode when playing the game, or it could be an additional command-line argument (--diff [map1] [map2] ?) for the game. (It could be a standalone application but that's probably going to end up with much more work for you.)


Add an option to not store replays

As noted in https://wiki.wesnoth.org/SavefileWML all normal savefiles usually contain [replay] and [replay_start] tags that usually take over 50% of the total savefile size and are only used for providing the possibilty to replay scenarios. It's be nice to have an option to skip these information to reduce the savefile size. Alternativeley one could create a tool inrtegated in a load/savegame dialog to remove the replay information from a given savegame file.

See the feature request https://github.com/wesnoth/wesnoth/issues/1457

MP related features

Add possibility to switch off mod dependency checking

MP modifications can define dependencies. Currently there's no way to force a "broken" configuration, although overzealous use of the system by UMC authors could make this feature useful. Add an option to the MP game creation screen to switch on/off dependency checking. Ask lipk (forum)/lipkab (IRC).


Make a header for the add-on when we organize scenarios by add-on in the MP create dialog

Using an established GUI technique to signal when one block of scenarios for an add-on ends and the next begins would make it much easier to use this dialog, if the user has several add-ons.

See one proposal here: https://github.com/wesnoth/wesnoth/issues/1365

Timer pause button

Longstanding feature request here: https://github.com/wesnoth/wesnoth/issues/1237

Request is for either a button, or a simple chat command like :pause, :unpause, to allow players to put the timer on hold if they are interrupted.

Ideally would be accompanied with a multiplayer-only scenario attribute "number_of_pauses" which decreases each time a client pauses the game. Pause should use a blindfold object to black out the screen, and send a chat message automatically when it occurs / resume occurs. For an example of how it might look, start a local hotseat mp game and enable the Preferences->General->Turn Dialog option. (This behavior was introduced in this commit: https://github.com/wesnoth/wesnoth/commit/bab03d554bea92f1ce6f585ef1123202173a3491)

Wintermute/happygrue also has other ideas about how the timer should/could work. For example, instead of their client ending their turn, the networked opponents could be required to "confirm" the time out. (This is probably a networked MP-only idea.)

A very fancy implementation might instead of a counter, allow the other players to vote on whether a pause request is granted.

Make sure that the paused client still responds to network commands, so that it is possible to kick a person who pauses and then doesn't ever unpause.

Add a "concede" button

Often times in mp, players concede the game before their leader is actually killed. When the game ends 'officially' the map is revealed, which can sometimes be instructive for the losing player. Additionally, it makes it easier to analyze the results of many games, for purposes of balancing, or for maintaining a ladder. So while it may seem small, this would actually be a pretty useful feature.

FIXME: figure out gh issue id

This could be implemented in lua.

Show [options] values in the mp lobby gameslist

It' be useful for newly joining payer to see the chosen [options] of a mp game, since most likeley there isn't enough space we could for example wigher show the options via an extra dropdown button in th elobby or show them in the mp waiting dialog instead.

See the featurerequest https://github.com/wesnoth/wesnoth/issues/1514

WML-related features

Side filter support in [item]

currently [items] allows a team_name= attribute to specify for which side the item is displayed, it would be better if [item] allowed a side filter to specify for which side the item is displayed.

See the bug report https://github.com/wesnoth/wesnoth/issues/1477

Support variable poison properties

See a feature request here:


Events Manipulation

  • [event] persistent="yes" - creates an event that lasts for the rest of the campaign
  • [disable_event][/disable_event] disables the event within which it appears (useful with conditionals). A more complex take on first_time_only=yes/no.

This is largely possible with event IDs, but could be useful when multiple copies of an event should be floating around


Game Information

  • [query_location] - queries a location from the user
    • variable
    • [filter_location]

Regarding [query_location]: probably a better name would be choose_location. This is used when a wml event is running and needs to get a target location hex from the user. For example, you right click on a catapult unit and choose the menu item "fire Catapult." Now a [message] says to click on any target within 5 hexes. Now [choose_location] is encountered and the mouse cursor changes to a target sign (possibly customizable). If the user's mouse drifts outside of the allowed locations it changes to a cancel icon. If the operation is cancelled then the variable is cleared and no location stored. --Sapient

This can be implemented in lua by using wesnoth.game_events.on_mouse_action and wesnoth.syncronize_choice


Improvements to AI

Existing bugs or undesirable features

Most of these are probably relatively easy to fix, although we can, of course, not guarantee that.

  • Feature: Convert E_NOT_REACHED_DESTINATION from an error to a warning.


  • Bug: Adding a candidate action mid-turn does not include it where it belongs in terms of its evaluation score. Instead, it gets added at the end of the candidate action list and might not be executed on the current turn, because other CAs with lower scores get evaluated first.


  • Bug: ai.get_new_enemy_dst_src and related functions have several problems:
    • They use the current moves of the enemy units, which generally are all zero.
    • Hexes occupied by other enemy units count as not reachable.
    • Working around this with a Lua wrapper makes this actually slower than ai_helper.get_enemy_dst_src, which makes the functions pretty much useless, as speed is the only thing speaking for them.


Add new features to the AI

  • Add a cost function to the C++ path finding code that takes avoided hexes into account, that is, hexes defined in an [ai][avoid] tag onto which the AI never moves. Also add an option to the Lua wesnoth.find_path() function with which using this cost functions can be turned on and off.
    • The background behind this task is the way how the default AI's move-to-targets candidate action works. It does path finding for units without taking avoided hexes into account, and afterwards eliminates moves for which the end point falls onto an avoided hex. As a result, some units might not move at all, even if it is, in principle, easily possible to move around an avoided area. The inclusion of the new path-finding in the AI's move-to-targets phase could therefore be a follow-up task.


  • Add a Lua function ai.get_individual_attacks() that returns all the single attacks the side can do (as opposed to attack combinations). This needs to include an option to recalculate and take the current situation on the map into account (making the function believe that the game state has changed).


  • Set up an option the allows us to exclude units from the move-to-targets phase similar to [filter_own] for the combat phase (other than setting ai_special=guardian, which has a number of other side effects). Actually, having this option for all CA's would be nice.


  • Change the aspects "passive_leader", "passive_leader_shares_keep", "leader_ignores_keep" to work with multiple leaders. The idea is to change the type of those aspects from yes/no to string so both "passive_leader=yes" and "passive_leader=leader_id_1,leader_id_2" is possible.


GUI2 features

Although mordante developed a new GUI system, GUI2, some dialogs still use the older GUI1 and could be improved or transferred. mordante has since disappeared, leaving GUI2's core code unmaintained; shadowm and vultraz should be able to answer most GUI2 (and even GUI1) related questions in his absence.

  • Information on the wiki can be found under GUIToolkit on the wiki.
  • The source code is under src/gui/
  • All mainline GUI2 WML resides in data/gui/default/

  • Make games sortable in the lobby (open slots, total number of players, era, XP modifier, gold per village, fog/shroud)


Debug mode

  • New debug command functionality (setting additional status.variables, possibly terrain)


For lossless png compression we use wesnoth-optipng, a script using an external toolchain (ImageMagick, OptiPNG, Advdef). Perhaps the performance could be improved by using PNGOut instead of advdef. This task includes

  • a quick profiling of compression ratio and decompression speed for both tools
  • if it provides a higher compression while not significantly slowing down decompression, adapt wesnoth-optipng to use PNGOut


See Also