From The Battle for Wesnoth Wiki
Revision as of 14:10, 17 October 2015 by TranceitionalMynd (talk | contribs) (Support variable village healing, variable poison properties)

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 context menu option for command mode

Make an alternate pathway to the command mode, normally activated with `:`. Some players have trouble getting used to this, a right click menu option may be easier for them.

See forum discussion here: http://forums.wesnoth.org/viewtopic.php?f=12&t=40300

Zappaman - 10/07/2014

Make a preference to disable the "automatic moves" at the beginning of a turn

There is already an option in the loadgame dialog to cancel all "planned" actions before loading your turn in SP. However it would also be nice esp. for MP to have a preference that would disable this behavior entirely, as for some players it can be quite frustrating.

See feature request here: https://gna.org/bugs/?9906 https://gna.org/bugs/?17195

Thanks to LovCAPONE for this.

Make a "play single move" button in the replay viewer

This is an often requested feature. The idea is to have a third `play` button which plays until a move or attack command appears, then stops again.


Thanks to Zappaman for this.

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.)

Make a GUI method to activate loggers

One of the tricks of the trade of WML programming is that you can turn on many helpful loggers to assist sometimes. For instance, there are many pitfalls related to carryover/transitioning scenarios that don't really generate sensible error messages, or give you a good idea of where to look to fix it. However, turning on --log-debug=engine/team_construction can provide you with the info that you need.

Unfortunately, this requires you to pass command-line arguments to the program, and is really most comfortable for Linux users. For Windows and OS X it is of course possible but many users will end up modifying a shortcut to achieve this, if they even know how to do it, and it's fairly awkward.

It would be nice if we had a page of checkboxes or radio buttons that could be reached from the title screen or from preferences, that could enable/disable the loggers for various channels. This would make it a lot easier for the typical user to take advantage of the logger output.

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://gna.org/bugs/?21653

Make it possible to host a game which only registered players are allowed to join

See feature request here: https://gna.org/bugs/?14138

Timer pause button

Longstanding feature request here: https://gna.org/bugs/?16733

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.

WML-related features

Support variable village healing, variable poison properties

See a feature request here:


Suggested approach -- new read/writeable values in wesnoth.game_config:


tranceitionalMynd - 10/17/2015 (ETA 11/7/2015)

Enhancements to Existing Actions

  • [fire_event] id=X - allow firing an event by id instead of by name
  • [allow_undo] {contents} - perform {contents} when move is undone.

[allow_undo] will probably need a method to re-fire the event on redo.

Events Manipulation

  • [event] recognized at the root level of the WML document (outside [scenario]) to define event handlers that are registered for the entirety of a campaign, as opposed to specific scenarios
  • [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

Automatically stored variables

  • $side_info - auto-stored side information
  • $game_info - auto-stored game information
  • $map_info - auto-stored map information

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: Make the (old) simple aspect syntax work when the Lua engine is defined for a side. Setting aspects in the [side] tag like this:

does not work if a Lua engine is defined in the tag. You either need to use the [aspect] tag in the [side] tag with 'engine=lua', or use the code above in a [modify_side] tag in an event. Making the above syntax available (as it is with the C++ engine) would be nice. The same also applies to the FAI engine and to aspects set for AI sides in MP games.

  • Feature: Convert E_NOT_REACHED_DESTINATION from an error to a warning.
  • Bug of sorts: AI move evaluation on maps with many guardians (units with ai_special=guardian) can take a very long time, even though those guardians don't move at all most of the time.
  • Bug: Adding a candidate action mid-term 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?: not all options/parameters of wesnoth.find_cost_map() work as described here. I don't know if that is a bug in the code or if the description on that page is wrong.
  • Mix of bugs and features: 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.
    • Units with zero moves are not listed at all, not even for the hex they are on.
    • 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.
  • Add new options (keys or tags) to the Micro AIs. As an example, some (but certainly not all) Micro AIs might benefit from taking some (but certainly not all) of the default AI aspects into account.
  • Write a script that automatically changes WML from the deprecated [ai][target] to the new [ai][goal] syntax. Ideally, this would be part of wmllint.
    • There are more deprecated AI aspect which should eventually be added to this, but the [target] -> [goal] change would be a good and important start.

GUI1 features

Widget changes

  • Make games sortable in the lobby (open slots, total number of players, era, XP modifier, gold per village, fog/shroud)
  • Input history and completion (for in-game and lobby chat, commands, etc.)

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/

Port the random map generator dialog to GUI2

The map generator currently doesn't use the GUI2 framework, but there's no reason why it couldn't.


More powerful village naming

Adding mountain names and other features to village names, having a second random name in village names

Currently the village naming engine has a very good structure that could allow more powerful names to be generated. Understanding how it works should be quite easy, and a few useful improvements could be added.

  • Currently villages can use lake names and river names, this should be extended to other features like bridges, swamps, mountains etc...
  • It would be nice to have a separate list of "first syllabus" and "last syllabus" for naming. That's not really needed in English, but some translations could use it
  • Again, it is common to have villages with more than one "random" word in them. having a $name2 variable would be nice

Turns out this was already done, and should be removed.

Use friends list as a fallback for tab completion

Currently wesnoth will use the list of current players, lobby members, as candidates for tab completion of names when whispering. The OP requests that the friends list also be merged in, in case one of your friends whispered you. Even better, could also remember names of anyone who whispered you in the last hour.


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