Difference between revisions of "NotSoEasyCoding"

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== Foreword ==
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This page lists projects which are considered a good idea by the developers, but which have nobody working on them so far. The tasks here are significantly more difficult than the ones in the similar [[EasyCoding]] page. If you think you've got the required skill for one of the tasks listed here, go on, implement it, and you've got a high chance that it'll be accepted. The remaining barrier will only be that it's done well. :-)
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This page shows projects which are considered a good idea by the developers but which have nobody working on them so far. If you think you've got the required skill for a task go on, implement it and you've got a high chance that it'll be accepted. The remaining barrier will only be that it's done well. :-)
 
  
 
If you are such a person, you should feel free to edit this page.
 
If you are such a person, you should feel free to edit this page.
  
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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.
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If you're not, you should post a feature request and discuss your idea on the forum or IRC or Discord. 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.
 
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.
  
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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 I'll "free" it back (that is if you're not working on it. If you have problems implementing it, just tell us....)
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If you plan to work on a feature, write your name at the bottom of the feature, with the date. Note that if you spend 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...). We sometimes forget to update this page so it is recommended that, before you start to work on a task, that you ask in irc/Discord whether its still considered a good idea.
  
 +
If you are part of the Wesnoth dev team you can also add new entries to the list, a new entry must contain at least
  
 +
1) A description of the problem.
 +
2) A motivation why or in which situations this is important.
 +
3) A link to a corresponding ticket on our bugtracker for discussion, if there is no ticket yet, then make one.
  
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== Game Engine ==
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__TOC__
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=== add a mode to improve OOS detection in MP ===
 
−
We really need an optional 'pedantic mode' for MP which detects OOSes immediately, by comparing all game state information after each action and printing any mismatches. This mode will be optional because of the extra overhead it adds, and it would be very useful for debugging.
 
  
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=== Fix a longstanding bug concerning failure to initialize a side in networked mp ===
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== Game engine ==
  
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https://gna.org/bugs/index.php?21397
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=== [[OpenGL port]] ===
  
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The problem itself is quite simple -- when the server tells a client that their turn has begun, the client immediately broadcasts [init_side] to all the other players via the server, performing the initial upkeep, healing, and movement point reset actions. However, if this player disconnects / blocks the action by opening a dialog during the prior turn and never closing it, [init_side] is never broadcast. And if the game is then saved by one of the other clients, nothing in the current mechanism detects that this has been overlooked when the game is reloaded. The consequence is that in the reloaded game, that side's turn is *never* initialized -- they get no gold, their units don't heal, and they don't get full move points at the start of the turn.
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While software rendering is all good and nice, Wesnoth's approach does not scale well as display resolutions increase and the need for supporting high DPI configurations is factored in. One can easily see that our zoom functionality is clunky and inefficient. Having support for OpenGL and shaders would also enable us to implement fancier graphical gimmicks such as particle effects and atmospheric lighting. The downside of adding OpenGL to the mix is that we'd need people with a specific skillset to help us maintain the graphics engine in the long term, as hardware and driver-specific quirks are inevitable. Some users are also concerned about changing Wesnoth's hardware requirements so that they would be unable to play using old or unsupported hardware/OS configurations.
  
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Propose a mechanism to fix this -- perhaps games which have been loaded should be scanned to see if the current turn failed to initialize. Perhaps a flag in game_state could be used and saved. Perhaps a completely different approach. Check that your mechanism works whether the save is loaded from [snapshot] or [replay_start] and [replay].
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For hardware rendering to be effective, in particular, Wesnoth would necessitate a complete rewrite of the graphics rendering code (the display and game_display classes), the image cache manager (used to abstract the process of loading images from disk and applying image path functions), and potentially GUI2's canvas code. All three would have to limit the amount of textures they allocate to the absolute minimum, using larger textures instead. For example, the image cache could be reimplemented to load images from an internal spritesheet generated during the game loading process. (WML/Lua support for spritesheets would be nice would defining an API for it would only distract from the actual task at hand.)
  
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This bug has existed since at least Wesnoth 1.8
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The greatest difficulty in handling this task probably lies in writing a new optimized rendering engine and updating all code that relies on the old display/game_display API and semantics accordingly. The GUI2 framework code is presently unmaintained and it would take some time for somebody to study and change the current implementation. Finally, as we don't have a graphics engine maintainer at this time, this task involves an implicit long-term commitment to the project that extends beyond whichever Wesnoth series that will see this project completed.
  
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=== Make a "replay actions since my last turn" button ===
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One of the many issues related to switching from software rendering to hardware rendering is Wesnoth's [[ImagePathFunctions]] mini-language. There is already a proof of concept [https://github.com/CelticMinstrel/wesnoth-ipf here] that converts most IPFs to OpenGL shader code, but quite a bit more work would need to be done to make something usable out of it. In particular, the ability to compile arbitrary [[Wesnoth Formula Language]] code into shaders would be needed, since some IPFs embed the language.
  
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It would be very convenient if there an ability to replay everything your opponents just did at the
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=== Improve WML error reporting ===
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start of your turn, since sometimes things go out of vision or are confusing.
 
  
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The feature would be like a "replay since my last turn" menu option or button -- most likely, the best approach to implement it is to store a copy of the game_state object in playcontroller.cpp or even in resources, and to refactor the backlog object so that we can hold a "bookmark", i.e. a pointer, to the last position in the replay that we might look to jump back to. The replay process would work by swapping out for the old gamestate, then replaying through the actions since the bookmark until we get back up to speed. The difficult part would be making sure that scenarios with scripted WML events don't break when we do this. For debugging purposes, it might be good to check that at this point we have the same gamestate we did before we clicked the button. The bookmark should only be advanced when we end our turn, and there might be perhaps need to be multiple bookmarks, one for each side, to handle what happens when a side disconnects or is reassigned.
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There are many programming bugs that give very unclear or cryptic error messages when using WML. Here are some examples:
  
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It would be especially helpful for MP play to have this, where special tactics with ambush units are quite common. Part of the design criteria of wesnoth is that it should be a high-level, thoughtful turn based strategy game, but you should be able to play asynchronously and not necessarily give attention to the game until your turn bell rings if you don't want to. Having ambush units and no ability to replay their movements during the opponents turn harms that goal.
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* <strike>When calling a macro with the wrong number of arguments, Wesnoth tells the number it expected, and the number it got, and at which line number it was instantiated. However, it would be helpful if it would also tell the line number of the definition of the macro. This might be helpful if someone is redefining macros.</strike>
  
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== MP Related ==
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* For places where a standard unit filter is expected, if one is not found, the game should point out a problem. For places where such a filter is expected but [filter] child should not appear, if one does it should report an error and a line number. Many users have a hard time with this kind of thing.
  
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=== Automatically resolve add-on dependencies ===
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* When doing scenario transitions in a campaign, if the side definitions don't match up exactly the game tends to give unintelligible error messages. For instance, if one is transitioning and there is an AI side which does not have a leader (but it has a starting location in the map) it must have "no_leader = yes" in its [side] tag, or else when the team_builder objects enter stage two, the game will try to create a unit with an empty type, and the constructor of class unit will fail giving the error message "game::game_error tried to create unit with empty type". This really needs to be much better. For instance, giving a line number of a problem, or suggesting that no_leader should be used. (Note that, it is often possible to debug problems like this by turning on --log-debug=team_construction at commandline but I doubt that there are any users that know about this, you would only learn from reading the C++... without such debug info, fixing things like this can literally take hours.) For that matter it's some question why the team_builder doesn't just stop trying to build a unit when it sees it doesn't have enough info...
  
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In 1.11 add-ons may declare dependencies. A related easy coding task is to allow the user to force breaking dependencies.
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* Recursive macros break the game, and not by stack overflow but by exhausting the heap (which usually takes forever on modern OSes and results in memory thrashing <i>before</i> resource starvation). It would be nice if we could catch this and report an error.
  
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A related goal which would be greatly beneficial would be that wesnoth can automatically resolve the dependencies by fetching the add-ons from the download server, when in the MP-lobby the user tries to join a game with a dependency they don't meet. A dialog would ideally be provided as well, or perhaps a preference.
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Many WML users are students or beginners to programming, so any improvements to WML error reporting are a big help for their learning process -- many veterans would appreciate the extra help as well. In part we need fixits here and there, but more broadly we need a smarter system that can figure out what's really wrong when things go wrong, and give helpful suggestions.
  
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https://gna.org/bugs/?21705
 
  
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Even older: https://gna.org/bugs/?9683
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=== Don't store all events in savefiles ===
 +
 
 +
Currently all events in a scenario are stored twice in each savefile (in [snapshot] and it [replay_start]), specially on wml-heavy umc content this can make savefiles quite big, The proposed solution is that events are not stored in savefiles when they are the same as in the scenario/era/modification file (e.g. not dynamically added with actionwml).
 +
In detail the savefile should for all events that have an id and are not generated dynamically ([event] actionwml), store dummy events like
 +
[event]
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  id=event_id
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  is_unchanged=yes
 +
[/event]
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in the savefiles (instead of full events), where the event is then read from the scenario/era/modification tag when the scenario is loaded. This should only apply to campaigns/modifications/mp maps/eras that require download (which is usually the case for campaigns but not for mp maps)
 +
 
 +
 
 +
See also https://github.com/wesnoth/wesnoth/issues/1512
 +
 
 +
== Multiplayer/replay features ==
  
 
=== Gold graph ===
 
=== Gold graph ===
  
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Make a graph feature, presumably in a dialog, that helps depict the history of the game. For example it could display army value, army + bank value, number of villages tagged, luck swings... the purpose would be to assist spectators of a live game / spectators of a replay to understand the history of the game. It would be particularly helpful with AI development, by helping AI developers to identify key points where one of the AI is making a big mistake.  
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Make a graph feature, presumably in a dialog, that helps depict the history of a Wesnoth match for the benefit of spectators of a live game or replay. For example it could display army value, army + bank value, number of villages tagged, luck swings... This would also be particularly helpful for AI tweaking development, by helping coders identify the AI's weaknesses and strengths in the context of a particular scenario.
  
 
A possible nice feature for this purpose would be to allow the user to click on the graph at key points which would trigger the "back to turn" mechanism to jump back in the replay, or automatically play the replay forwards from the beginning to that point... etc.
 
A possible nice feature for this purpose would be to allow the user to click on the graph at key points which would trigger the "back to turn" mechanism to jump back in the replay, or automatically play the replay forwards from the beginning to that point... etc.
  
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Related email on dev-talk: https://mail.gna.org/public/wesnoth-dev/2014-02/msg00089.html
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Related email on dev-talk: http://web.archive.org/web/20170505024430/https://mail.gna.org/public/wesnoth-dev/2014-02/msg00089.html
  
 
=== Automatically link up to wesnothd server on a local network ===
 
=== Automatically link up to wesnothd server on a local network ===
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The feature request was to use ZeroConf technology, if available, to publish info of a running wesnothd instance to other machines on a local network. Then when they are searching to connect to an unofficial server, they won't have to learn the IP address.
 
The feature request was to use ZeroConf technology, if available, to publish info of a running wesnothd instance to other machines on a local network. Then when they are searching to connect to an unofficial server, they won't have to learn the IP address.
  
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The extra code should be guarded with preprocessor flags so that ZeroConf does not become a build dependency of wesnoth.
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The extra code should be guarded with preprocessor flags so that ZeroConf does not become a mandatory build dependency of Wesnoth.
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https://gna.org/bugs/?13703
 
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== Improvements to AI ==
 
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=== Move and targeting phase ===
 
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AI needs to move units which are not within range of the enemy. This is generally a sequence of moves (some interesting things like 'ambush!' or 'WML event' might happen as a result of those moves, which should interrupt this phase). The problem is that simply doing those moves 1-by-1 is very slow, for two reasons:
 
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#movement maps are invalidated after each move, and are recalculated from the start. yet, if we are doing just a sequence of moves, we can just 'remove moved unit from moves' after each move and avoid expensive recalculation of the movement map.
 
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#* Note that WML could mess with the game state at any time, so at the very least, movement will need to be recalculated after a WML event blocks undo (that is, indicates that it changed game state). --[[User:Brilliand|Brilliand]] 01:30, 28 May 2012 (UTC)
 
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#most tasks need devoting more than one unit to execute (i.e., it's meaningless to go for the enemy position with just 1 unit). So, making individual decisions just does some repeating calculations, which is slow.
 
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A practical demonstration of these concerns are LoW 2 (dwarf ai is slow due to large avoid aspect) and NR:Showdown (orc AIs there are slow because of huge number of units)
 
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we need a fast and effective 'move and targeting stage' - both ideas and implementations are wanted.
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https://github.com/wesnoth/wesnoth/issues/1162
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Here's Sirp's idea (more in 2009-aug-15 irclog):
 
  
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--
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=== Stock MP chat messages for language-independent communication ===
  
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=== Eval-based AI ===
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Wesnoth has seen a large acceptance by international communities, and many players don't speak English. It would be nice we could have a set of messages that could be chatted, but which will be translated by our translators and displayed always in the current locale on each client, to make it easier to communicate in mp games / on the mp server.
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The AI system would be based around an 'eval' function -- a formula which is given a position, and returns a number saying how attractive that position is.
 
  
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There would also be a 'candidate_moves' function -- a formula which is given a unit and returns a list of 'candidate moves' -- i.e. moves for that unit that the AI should consider making.
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The easy part is adding the messages. They would ideally be stored in a WML file in the core data dir so they can be easily modified and translated like all other mainline WML. The hard part is devising the interaction mechanism so that a player can easily make use of these stock messages in the MP lobby or in game.
  
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The aim of the system is to come up with the combination of candidate moves that gives the best possible evaluation. By doing this, the AI will work in a team, since the 'eval' function can give bonuses for units being close together, protecting each other, etc.
 
  
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There are likely to be, of course, a very large combination of possible moves, and not every one can possibly be evaluated. Instead, we take a monte carlo approach.
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== GUI2 framework ==
  
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If an AI has N units that it can move, that is an N-dimension matrix of possible moves. We would choose some cells in this matrix at random and then evaluate them. Then, of these cells evaluated we would choose cells that evaluated well, and discard those that did not evaluate well. Then, we would begin with those cells that evaluated well, and choose a scattering of 'close by' cells -- i.e. cells where we only vary some of the dimensions, at random. We would continue to evaluate cells at random, starting with those cells that evaluated well, and evaluating cells nearby. After several iterations, we would hope to arrive at a cell that evaluates very well, and we would use this as our set of moves.
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As of 1.13.1+dev, GUI2's core and framework (including widgets and their APIs) are completely unmaintained. A prospective maintainer would have to be able to understand pretty advanced C++ making abundant use of template-based abstractions (most notably, the event handling code is almost completely implemented this way), multiple inheritance, and polymorphism. There is also some missing functionality (such as combo boxes and modeless dialogs) that the author did not get to implement, as well as work-in-progress functionality (new listbox and tooltip implementations, not enabled by default).
  
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Of course, this system will be made more complex by the uncertainty of attacks. There are a number of ways to handle attacks, probably the easiest being to consider attacks as types of moves, and then if a move combination involving an attack is chosen, perform the attack and then re-run the entire AI algorithm before moving again. (Something similar to what the current AI does).
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=== GUI2 themable in-game UI ===
  
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This is effectively an AI framework, not an AI in itself. How well it performs will correlate strongly with how good an eval() function one can write, and is also based on the notion that generally certain combinations of moves are 'similar' to other combinations.
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The "themable" in-game UI refers to the gameplay UI including the sidebar, menu/status bar, and map view. Most of it is not implemented using proper GUI1 widgets at all, except for the various interactive buttons, menus (which are floating GUI1 listboxes), and the command and chat input boxes (floating GUI1 textboxes).
  
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--
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Moving the theme UI to GUI2 would probably require finishing up theme support in GUI2 (which is largely incomplete), and may benefit from a rendering engine redesign as is also required for porting the game to SDL 2; in particular so that the GUI aspects are more clearly separated from the game board rendering aspect.
  
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=== Village grabbing ===
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'''Note:''' This task is here solely for the sake of completeness, and only somebody very well versed in the intricacies of Wesnoth's game rendering code and GUI2 should '''ever''' try to take it up. (And even then, I would not want to be anywhere near that person when they inevitably break down and fling one or more tables around upon realizing the sheer complexity of the task. -- Iris)
  
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Improve AI village grabbing algorithm to assign villages that are farther than one turn from current unit location.
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== Add-ons server and client ==
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Idea how to do would be value villages so that it can filter out villages that belongs to enemies/allies sides.  Those villages are stored in memory and used in 2nd pass that determines how AI should dispatch units to get villages if it should at all in this turn. This should be close to optimal solution with currently available units but performance limits should be taken into account.
 
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Good solution would be that village grabbing value could be calculated with attack ratings and if some village has high value it would make unit go for that village instead
 
  
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This should help AI in begin of scenario. Currently AI might not grab all of villages that belong to its area which results quite large incoming loses.
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=== Passphrase hashing ===
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In later game enemy might have large number of units in one part of map so village grabbing should be avoided in that are. Single unit would be easy pray for enemy so moving there would result just to loses.
 
  
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== Data Structures ==
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The add-ons server ([[campaignd]]) uses a very dumb authentication scheme for uploading add-ons where an author sets a passphrase (or gets a random passphrase assigned by the game) the first time they upload to the server, and subsequent uploads of the same add-on are only allowed if the passphrase matches. The passphrase is stored in clear text form both client and server-side, which has [http://forums.wesnoth.org/viewtopic.php?f=62&t=42663 various implications].
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=== Config Writer ===
 
  
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The speed of saving Wesnoth games is dominated by the time to marshall all the config structures.  This involves deep copying them many times as each subsystem returns its config bundle; far better would be to have a "config_writer" class which is handed to each subsystem which iterates through its structures and does the writing (to file or network) directly to the config_writer instance.
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Ideally, the server would store all passphrases in a hashed form.
  
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Stop by #wesnoth-dev on freenode irc if you want to help with this, or post in the Coder's Corner.
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=== Port redirection ===
  
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=== Config memory optimisation ===
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Wesnoth's MP server (wesnothd) uses a single port (15000) for servicing most requests and redirects clients to different ports according to the game client's version number. This allows the server administrators to reassign ports freely without having to modify the game client.
  
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Right now, most of the memory used by wesnoth when using '''low_memory''' configuration flag is used by the config object trees. It would be possible to drop unused "branches" of that trees by using boost smart pointers in the config structure
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The add-ons server (campaignd) and client instead have a hardcoded default port number for a Wesnoth version series. For example, 1.12.x is hardcoded to default to 15006. This becomes a maintainability issue as add-on servers get decommissioned and their port numbers can't be reused for fear of misdirecting obsolete client versions to the wrong instance with incompatible add-ons.
  
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come and discuss that change on #wesnoth-dev. Sirp is the one that knows the most about that...
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== Multiplayer server and client ==
  
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=== Improvements to Unit Map ===
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=== Improve server WML processing ===
  
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As described here: [http://www.wesnoth.org/forum/viewtopic.php?p=236063#236063] (cjhopman has submitted a patch on that already)
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The server uses its own custom WML implementation separate from the main engine's to store and process WML objects for games -- see [[WesnothdDesign#simple_wml]]. This is intended to improve performance and reduce wesnothd's memory footprint with large numbers of games and complex scenarios. However, the simple_wml code sometimes messes up WML attribute translatability, resulting in MP scenarios/campaigns being untranslated for non-hosts in networked MP (https://github.com/wesnoth/wesnoth/issues/1420). Fixing this is not easy due to the aforementioned performance requirements.
  
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== See Also ==
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== WML-related features ==
 +
=== Game Information ===
  
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=== Frequently Proposed Good Ideas ===
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* [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''
  
−
Check the [http://www.wesnoth.org/forum/viewtopic.php?f=12&t=9054&start=0&st=0&sk=t&sd=a B.W.H. list] in the Ideas Forum. Be aware that some entries there are old and have already been implemented, so you will need to investigate that before beginning work.
+
''This can be implemented in lua by using wesnoth.game_events.on_mouse_action and wesnoth.syncronize_choice''
  
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[[Category:Development]]
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https://github.com/wesnoth/wesnoth/issues/2325
−
[[Category:Future]]
 

Latest revision as of 20:08, 6 June 2024

This page lists projects which are considered a good idea by the developers, but which have nobody working on them so far. The tasks here are significantly more difficult than the ones in the similar EasyCoding page. If you think you've got the required skill for one of the tasks listed here, go on, implement it, and you've got a high chance that it'll be accepted. The remaining barrier will only be that it's done well. :-)

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 or Discord. 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 spend 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...). We sometimes forget to update this page so it is recommended that, before you start to work on a task, that you ask in irc/Discord whether its still considered a good idea.

If you are part of the Wesnoth dev team you can also add new entries to the list, a new entry must contain at least

1) A description of the problem. 2) A motivation why or in which situations this is important. 3) A link to a corresponding ticket on our bugtracker for discussion, if there is no ticket yet, then make one.

Game engine

OpenGL port

While software rendering is all good and nice, Wesnoth's approach does not scale well as display resolutions increase and the need for supporting high DPI configurations is factored in. One can easily see that our zoom functionality is clunky and inefficient. Having support for OpenGL and shaders would also enable us to implement fancier graphical gimmicks such as particle effects and atmospheric lighting. The downside of adding OpenGL to the mix is that we'd need people with a specific skillset to help us maintain the graphics engine in the long term, as hardware and driver-specific quirks are inevitable. Some users are also concerned about changing Wesnoth's hardware requirements so that they would be unable to play using old or unsupported hardware/OS configurations.

For hardware rendering to be effective, in particular, Wesnoth would necessitate a complete rewrite of the graphics rendering code (the display and game_display classes), the image cache manager (used to abstract the process of loading images from disk and applying image path functions), and potentially GUI2's canvas code. All three would have to limit the amount of textures they allocate to the absolute minimum, using larger textures instead. For example, the image cache could be reimplemented to load images from an internal spritesheet generated during the game loading process. (WML/Lua support for spritesheets would be nice would defining an API for it would only distract from the actual task at hand.)

The greatest difficulty in handling this task probably lies in writing a new optimized rendering engine and updating all code that relies on the old display/game_display API and semantics accordingly. The GUI2 framework code is presently unmaintained and it would take some time for somebody to study and change the current implementation. Finally, as we don't have a graphics engine maintainer at this time, this task involves an implicit long-term commitment to the project that extends beyond whichever Wesnoth series that will see this project completed.

One of the many issues related to switching from software rendering to hardware rendering is Wesnoth's ImagePathFunctions mini-language. There is already a proof of concept here that converts most IPFs to OpenGL shader code, but quite a bit more work would need to be done to make something usable out of it. In particular, the ability to compile arbitrary Wesnoth Formula Language code into shaders would be needed, since some IPFs embed the language.

Improve WML error reporting

There are many programming bugs that give very unclear or cryptic error messages when using WML. Here are some examples:

  • When calling a macro with the wrong number of arguments, Wesnoth tells the number it expected, and the number it got, and at which line number it was instantiated. However, it would be helpful if it would also tell the line number of the definition of the macro. This might be helpful if someone is redefining macros.
  • For places where a standard unit filter is expected, if one is not found, the game should point out a problem. For places where such a filter is expected but [filter] child should not appear, if one does it should report an error and a line number. Many users have a hard time with this kind of thing.
  • When doing scenario transitions in a campaign, if the side definitions don't match up exactly the game tends to give unintelligible error messages. For instance, if one is transitioning and there is an AI side which does not have a leader (but it has a starting location in the map) it must have "no_leader = yes" in its [side] tag, or else when the team_builder objects enter stage two, the game will try to create a unit with an empty type, and the constructor of class unit will fail giving the error message "game::game_error tried to create unit with empty type". This really needs to be much better. For instance, giving a line number of a problem, or suggesting that no_leader should be used. (Note that, it is often possible to debug problems like this by turning on --log-debug=team_construction at commandline but I doubt that there are any users that know about this, you would only learn from reading the C++... without such debug info, fixing things like this can literally take hours.) For that matter it's some question why the team_builder doesn't just stop trying to build a unit when it sees it doesn't have enough info...
  • Recursive macros break the game, and not by stack overflow but by exhausting the heap (which usually takes forever on modern OSes and results in memory thrashing before resource starvation). It would be nice if we could catch this and report an error.

Many WML users are students or beginners to programming, so any improvements to WML error reporting are a big help for their learning process -- many veterans would appreciate the extra help as well. In part we need fixits here and there, but more broadly we need a smarter system that can figure out what's really wrong when things go wrong, and give helpful suggestions.


Don't store all events in savefiles

Currently all events in a scenario are stored twice in each savefile (in [snapshot] and it [replay_start]), specially on wml-heavy umc content this can make savefiles quite big, The proposed solution is that events are not stored in savefiles when they are the same as in the scenario/era/modification file (e.g. not dynamically added with actionwml). In detail the savefile should for all events that have an id and are not generated dynamically ([event] actionwml), store dummy events like 

[event]
 id=event_id
 is_unchanged=yes
[/event]

in the savefiles (instead of full events), where the event is then read from the scenario/era/modification tag when the scenario is loaded. This should only apply to campaigns/modifications/mp maps/eras that require download (which is usually the case for campaigns but not for mp maps)


See also https://github.com/wesnoth/wesnoth/issues/1512

Multiplayer/replay features

Gold graph

Make a graph feature, presumably in a dialog, that helps depict the history of a Wesnoth match for the benefit of spectators of a live game or replay. For example it could display army value, army + bank value, number of villages tagged, luck swings... This would also be particularly helpful for AI tweaking development, by helping coders identify the AI's weaknesses and strengths in the context of a particular scenario.

A possible nice feature for this purpose would be to allow the user to click on the graph at key points which would trigger the "back to turn" mechanism to jump back in the replay, or automatically play the replay forwards from the beginning to that point... etc.

Related email on dev-talk: http://web.archive.org/web/20170505024430/https://mail.gna.org/public/wesnoth-dev/2014-02/msg00089.html

Automatically link up to wesnothd server on a local network

The feature request was to use ZeroConf technology, if available, to publish info of a running wesnothd instance to other machines on a local network. Then when they are searching to connect to an unofficial server, they won't have to learn the IP address.

The extra code should be guarded with preprocessor flags so that ZeroConf does not become a mandatory build dependency of Wesnoth.

https://github.com/wesnoth/wesnoth/issues/1162

Stock MP chat messages for language-independent communication

Wesnoth has seen a large acceptance by international communities, and many players don't speak English. It would be nice we could have a set of messages that could be chatted, but which will be translated by our translators and displayed always in the current locale on each client, to make it easier to communicate in mp games / on the mp server.

The easy part is adding the messages. They would ideally be stored in a WML file in the core data dir so they can be easily modified and translated like all other mainline WML. The hard part is devising the interaction mechanism so that a player can easily make use of these stock messages in the MP lobby or in game.


GUI2 framework

As of 1.13.1+dev, GUI2's core and framework (including widgets and their APIs) are completely unmaintained. A prospective maintainer would have to be able to understand pretty advanced C++ making abundant use of template-based abstractions (most notably, the event handling code is almost completely implemented this way), multiple inheritance, and polymorphism. There is also some missing functionality (such as combo boxes and modeless dialogs) that the author did not get to implement, as well as work-in-progress functionality (new listbox and tooltip implementations, not enabled by default).

GUI2 themable in-game UI

The "themable" in-game UI refers to the gameplay UI including the sidebar, menu/status bar, and map view. Most of it is not implemented using proper GUI1 widgets at all, except for the various interactive buttons, menus (which are floating GUI1 listboxes), and the command and chat input boxes (floating GUI1 textboxes).

Moving the theme UI to GUI2 would probably require finishing up theme support in GUI2 (which is largely incomplete), and may benefit from a rendering engine redesign as is also required for porting the game to SDL 2; in particular so that the GUI aspects are more clearly separated from the game board rendering aspect.

Note: This task is here solely for the sake of completeness, and only somebody very well versed in the intricacies of Wesnoth's game rendering code and GUI2 should ever try to take it up. (And even then, I would not want to be anywhere near that person when they inevitably break down and fling one or more tables around upon realizing the sheer complexity of the task. -- Iris)

Add-ons server and client

Passphrase hashing

The add-ons server (campaignd) uses a very dumb authentication scheme for uploading add-ons where an author sets a passphrase (or gets a random passphrase assigned by the game) the first time they upload to the server, and subsequent uploads of the same add-on are only allowed if the passphrase matches. The passphrase is stored in clear text form both client and server-side, which has various implications.

Ideally, the server would store all passphrases in a hashed form.

Port redirection

Wesnoth's MP server (wesnothd) uses a single port (15000) for servicing most requests and redirects clients to different ports according to the game client's version number. This allows the server administrators to reassign ports freely without having to modify the game client.

The add-ons server (campaignd) and client instead have a hardcoded default port number for a Wesnoth version series. For example, 1.12.x is hardcoded to default to 15006. This becomes a maintainability issue as add-on servers get decommissioned and their port numbers can't be reused for fear of misdirecting obsolete client versions to the wrong instance with incompatible add-ons.

Multiplayer server and client

Improve server WML processing

The server uses its own custom WML implementation separate from the main engine's to store and process WML objects for games -- see WesnothdDesign#simple_wml. This is intended to improve performance and reduce wesnothd's memory footprint with large numbers of games and complex scenarios. However, the simple_wml code sometimes messes up WML attribute translatability, resulting in MP scenarios/campaigns being untranslated for non-hosts in networked MP (https://github.com/wesnoth/wesnoth/issues/1420). Fixing this is not easy due to the aforementioned performance requirements.

WML-related features

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

https://github.com/wesnoth/wesnoth/issues/2325

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This page was last edited on 6 June 2024, at 20:08.