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TODO

Revision as of 09:27, 14 November 2008 by Fingolfin (talk | contribs) (→‎General)

Here is a list of things we consider doing in the future. Note that we don't promise to do any of these, nor when we will do them. It's just a list of what we hope to be able to do one day, and some items on the list really are more like ideas than real proposals, so take it with a grain of salt.

If you want to dig in, this is the stuff where you might make the most useful contribution. Note that this list is never complete, and may be partially outdated, so just because you don't see something here doesn't mean it is not important.

Before you start work on something, you should first talk to the team! Ideally ask on scummvm-devel, our mailing list. This will help us to prevent double work, i.e. several people working on the same stuff at once without knowing about each other. Furthermore, sometimes entries on our list are actually obsolete (because the feature has been implemented, or because for some reason we no longer think it to be desirable). Special caution should be taken for TODO entries that say "we may want to" or similar things; that usually means that we aren't sure whether we really want to implement that feature.

So, to repeat it: Always talk to the team before implementing a change on this list, or else risk having your patch rejected :-/.

Finally, always make sure to check out our bug tracker and our feature request tracker for things that need work.


Docs, Web site

See also the Documentation/TODO page.

General

  • Add port specific user documentation (dreamcast/palm especially). That would include things like:
    • How to use ScummVM on system XYZ
    • Which Palm / WinCE devices will run ScummVM, which definitely will not run it (or with which limitations)?
  • Update/enhance man page
  • Write a high level overview of how ScummVM and its engines work?

README / Manual

  • Fingolfin has started a DocBook based manual (and FAQ, and Developer's Guide). You can find it in the SVN module "docs". It's a starting place, but very unfinished.
  • Everybody is welcome to start helping out with the public manual project in the "docs" SVN module. You can either reuse content from the README, or replace it with new, better written stuff. Contact Fingolfin or our mailing list, scummvm-devel, if you are interested in helping out.
  • Maybe move all/most of the compression related stuff from our README completely to the tools README, and only leave a pointer to that in the main README. This would be beneficial because this way, it's only documented in one place; it's *completly* documented (currently, the main README doesn't mention compress_scumm_bun, for example); and people who want to use the compression tools need to download the tools package anyway.
  • It would be greate to have a "Developer's Guide to ScummVM" which explains the ScummVM framework, and also the engines, i.e.
    • stuff in common/, like the config manager etc.
    • the backend API, and how to create new backends
    • the sound system
    • how to create a new engine
    • a chapter for each engine, with as many/little details as the resp. engine teams deem appropriate...
    • ...

Code

  • Add more Doxygen comments. However, quality is preferable over quantity
  • Document the OSystem overlay API, it badly needs it...

Web site

  • Add the "Manual" / README to the site

Wiki

  • Add content for the Wanted Pages
  • Add some content to the Help:Editing link you see when editing a page.
  • Create visual theme which will loosely fit our forum and website

Common code, infrastructure

General

  • Revise the way "quit" is handled. Maybe add a global variable "g_quit" which we set when the application should be quit (e.g. when an EVENT_QUIT is received). This is useful if multiple levels of event loops have to be ended
  • Make some generic "EventLoop" API/class which all backends and the GUI use. Initially this would just call the backend poll_event() etc. methods. But eventually the EventLoop object(s) could be made by the backend. This may allow for more efficient CPU usage etc. The current event handling model essentially is polling: the engines run some kind of main loop, which, besides many other things, also polls and dispatches events. The idea is to turn this around: the event loop frequently gives the engine time to do these "other things".
  • Maybe add ways to modify the game configs via the command line. E.g. allow
   ./scummvm --add new_target --path=/foo monkey2
   ./scummvm --remove new_target
  • Maybe allow launching games even if no target is specified? I.e. the user only has to specify a path (or run ScummVM from the right directory), and ScummVM auto-detects the game in that location
   ./scummvm --auto-detect
  • The following things should be put into namespaces:
    • MIDI related classes either to Audio, or a new "MIDI" namespace
    • backend specific stuff into ??? (maybe new namespace "Backends" ?) not sure about this one.
  • Get rid of getenv in as many places as possible. Ideally, we'd only use it to query HOME on Unix systems.

Iterator handling

  • Implement proper reverse_iterators for Common::List. Our current implementation is the same as forward iterators, just that rbegin will return the last element instead of the first and there is no rend. Check SGI Documentation for proper description of revese_iterator in the STL.

Event recorder

Currently there is an implementation based on patch #1738058 but it needs more work

  • Try to avoid warpMouse() calls at playback, so the system will be useable
  • Perhaps we need to indicate recording mode. May be draw triangle/circle in some corner. Use OSD overlay for that
  • Still it is possible that time will drift away even with current implementation. Do something about it, at least try to detect
  • Remove temporary file
  • Perhaps autogenerate record file name based on target name
  • Perhaps combine 2 files which get created currently into one
  • We should store unique game ID in the record files. I.e. ideally it should be engine name and some game MD5 or anything else which could be re-generated on game start. Then when this method is called in playback mode, recorder matches this against values stored in the record and refuses to play if they do not match.
 registerGame("scumm", "60ba818dc3bede86d40357e3913f8505");


  • Perhaps add special flag when game started from a save, i.e. not from the very beginning but with -x command line switch.
  • getMillis() currently is hacked into SDL. It has to be moved one level up
  • delayMillis() perhaps has to be wrapped too, so time drift could be avoided

Build System

  • Add test(s) for backend usability in the configure script.
  • Add an install target to the Makefile - Copy binary, install manpage, add menu items, install README. See also patch #891909 (Gnome/KDE .desktop file)
  • Create a script (probably with perl) which parses the module.mk files and creates the MSVC project files from it. Shouldn't be too difficult.
  • Investigate whether switching to CMake or SCons or some other cross platform configuration environment would work for us. Potential advantage: Less effort to maintain and extend the build system, automatic generation of various kinds of project files (Makefiles, and project files for MSVC, XCode, Eclipse, KDevelop ...). Potential drawback: Problems with the customized build systems of our various ports. However, the latter might actually be improved by using CMake or SCons -- hard to say without tests.

Audio

Mixer

  • Get the high quality resample code to work
  • Consider changing the mixer volume to use range 0-255, for sake of consistency (but at a slight loss of efficiency). Note that this requires changes in at least rate.cpp and mixer.cpp.
  • Some of our engines support the speech_mute / sfx_mute / music_mute options, but most don't. Almost all support the corresponding FOO_volume config keys. All engines use Mixer::setVolumeForSoundType to push those through to the mixer. I am wondering: Maybe it would make sense to remove Mixer::setVolumeForSoundType, and instead leave it up to the mixer to query the ConfigManager for the corresponding FOO_volume/_mute values? That way we'd ensure 100% identical behavior in all engines and actually simplify the code a bit... ? Not sure if this would work smoothly, it needs to be investigated.
  • change the way the mixer is instantiated by the backend. In particular, it would be nice if the sample rate could be passed in via the constructor
  • the "isReady" code is irritating. Most engines ignore it anyway. It's primary purpose is to allow ScummVM to run even if not digitial audio out is available. A better solution would likely be to implement a fake mixer class, which simply discards audio data which is passed to it immediately. This means that the normal mixer will always consider itself to be "ready", and that it will be up to the backend to use the "fake mixer" if it can't provide audio out for some reason.

Audio streams

  • Add a "SeekableAudioStream" class, which would allow seeking in an audiostream: Forward / backward; offset is specified in milliseconds. Then, convert at least the MP3/FLAC/Vorbis audiostream classes to subclass that, and also adapt the corresponding factory functions. Converting more would obviously be nice, too.

CD

  • Consider extending the Audio CD Manager with WAV or VOC support (essentially, the WAV/VOC code would need to be enhanced by adding a factory function similar to that provided for the FLAC/Vorbis/MP3 streams).

MIDI

  • See also Music drivers redesign
  • MIDI: Add API to OSystem which allows client code to query for "native" MIDI drivers (like Windows, ALSA, Zodiac, CoreAudio). Then change the MIDI interfacing code (GUI, command line, config file, etc.) and also MidiDriver::createMidi() to use both that list and the list of 'emulated' MIDI devices (Adlib, MT-32, PC Speaker, etc.) in an appropriate way.
  • Make it possible to pass options to the midi/music drivers. This would allow us to get rid of the getenv hacks in the alsa & seq drivers.
    • A simple approach would be to allow the user to specify "extended" driver descriptions. E.g. "alsa:1234" could indicate the alsa driver with port 1234; alternatively, "alsa:port=1234".
    • This doesn't allow for easy tweaking of those settings via the GUI.... to achieve that, one approach would be to invent a 'parameter description language' which allows a driver to specify which options with which kind of values it supports... very flexible, but possibly overkill.
    • Instead, one could add a hook method to MIDI drivers that let's them add a few controls of their own to the options dialog. This is probably a lot easier to implement, though not quite as "clean"...
  • Our XMIDI parser seems to have a couple of missing features, but it's unclear which ones are actually needed. For instance, Kyrandia 1 (and probably 2) uses the XMIDI mechanism for looping, which we currently implement through a very simple hack. The Exult project may have a good reference implementation.

Config Manager

  • Add a 'notification' system. E.g. the SoundMixer could request to be notified whenever the value of the "volume" config option changes. In other words, instead of a "pull" approach (where each subsystem has to check whether any config option relevant to it has been changed) we use a "push" approach. Of course the current approach is "push", too: whenever e.g. the volume setting is changed, the code doing so has to updated the SoundMixer etc. That's cumbersome, and error prone. Would be much nicer if updating the volume config value automatically notifies the SoundMixer, iMuse etc.
  • Modify the ConfigManager to make use of the ConfigFile class.
  • Maybe even follow the pentagram (http://pentagram.sf.net) approach and have three classes:
    • SettingsManager (like our current ConfigManager)
    • ConfigFileManager (manages a set of config files, possibly merging the data from multiple config files)
    • ConfigFile (a simple .ini file accessor).
    This makes it easy to add additional config sources (e.g. XMLConfigFile); makes it possible to treat the command line data like another config file (CommandLineConfig); and simply follows the good old MVC approach, which is always a good idea.

Files

  • Don't rely on the existence of SEEK_CUR, SEEK_END, SEEK_SET -- rather, define our own enum for this and convert all client code to use it.
  • Try to replace all usages of paths by FilesystemNode. In particular, Engine::_gameDataPath and File::addDefaultDirectory() will have to be adjusted. The idea behind this is to ease portability. Or, come up with a completely new system for this (see also recent discussions on scummvm-devel).

GUI

Plugins

  • On OSX: Support a plugin build in the bundle target: *.plugin files should be put into ScummVM.app/Contents/PlugIns/; this also means that the loader needs to search in the plugin dir of the active bundle. So use the CF bundle API, inside a #ifdef MACOSX block.
  • Make DetectedGame::updateDesc a normal function, not a member function.

Launcher

  • Enhance the Mass detector to show a list with the results (and optionally, allow the user to edit/cull that list before adding it).
  • Game edit dialog: Consider adding some warnings to the platform/language fields ("Don't mess with these unless you know what you are doing"), or move them to an "advanced" tab
  • Make the gameid editable via an "advanced" tab entry?
  • There is no way to reset the save/extra/theme paths. Adding a tiny button labeled "c" for clearing them (like for the soundfont path button) is not the way to solve this, I think. One approach would be to extend the Browser dialog, to allow an (optional) extra button, with customizable label. When pressed, the browser dialog closes and returns a special code. Well, and we'd use labels like "Use default savepath" or "Reset extrapath", or just always "Use default value".

Global Main Menu/Return to Launcher

  • Double Quit Confirm Dialogs: When confirm exit is enabled in ScummVM, the ScummVM quit confirm dialog shows up in addition to the quit confirm dialogs for those games which have their own. For example, when you select 'Quit' from Beneath a Steel Sky's in-game menu, it asks you if you really want to quit. Then, after answering, ScummVM gives you another dialog asking you if you really want to quit. So, ScummVM should not show the quit confirm dialog if the in-game dialog has already been displayed. This affects any game which has it's own menu system from where you can quit, or has a native quit confirm dialog. So this means most games.
  • Options Dialog: Implement engine flags to define which features in the Options dialog are supported by the current running game. Use these flags to hide/show the appropriate sliders and buttons in the Options Dialog
  • Improve the look of the GMM: This could include displaying the engine name and the ScummVM logo somewhere on the GMM.
  • Config Dialog code: Resolve the FIXME in engines/dialogs.cpp which pertains to having to use the empty string as the domain name.


Engines / frontends

SCUMM

AGI

AGOS

Cine

Drascula

Gob

Kyra

MADE

Parallaction

SAGA

Broken Sword 1

  • Modify MoviePlayer class to use ManagedArray for _movieTexts.

Broken Sword 2

  • Fix the credits so they look more like the original. (Did we ever get the source code for that?)
  • Maybe work around script bug which causes the mop to disappear briefly when trying to pick it up from the top of the boat at the London docks. (The event to hide the mop is sent too early.) See bug #1214168.
  • Unify some of the code with Broken Sword 1 (e.g. in router.cpp).

Touche

Backends

General

  • Add API to query backend for a list of available music engines. Useful for Options dialog. See Music drivers redesign.
  • Right now gBitFormat is part of common/scaler.cpp; we might want to move it to common/system.cpp, or replace it with something better. No hasty changes here, please, make sure you understand how it is used right now before messing with it ;-)

SDL backend

  • Right now, the WinCE and the Symbian backend subclasses the regular SDL backend. They both overload a lot of methods (mostly the graphics stuff). Since graphics.cpp uses the scalers (e.g. hq3x), these derived backends carry that baggage around, too, even though they don't need that code. Idea: split the SDL backend into two classes, one base class which only has the code which is used by all subclasses; and a "desktop" subclass, which implements the rest. Then WinCE/Symbian would only subclass the "base" SDL class.
  • We implemented GFX transactions & commits some time ago -- but they are only half the story. We are still missing a rollback system -- that is, check whether the requested video mode works, if it doesn't, revert to the current settings -- at least "if it makes sense". That is, if the transaction only modified the scaler or aspect ratio, we can safely revert. Of course if the screen size changed (e.g. from 320x200 -> 640x480) we can't just revert to the old screen size -- unless we augment the API accordingly, and update all engines to deal with this possibility.
  • The kFeatureAutoComputeDirtyRects feature is not entirely reliable, and perhaps it cannot ever be. It is currently known to cause glitches in The Feeble Files.

WinCE backend

  • Improve the code in backends/platform/wince/CEScaler.cpp, it could be a lot faster with some simple changes.

Tools

General

  • Use doxygen (or something else) to turn the short descs from the README into short man pages AND a single text file (replacing README) and a HTML file...

Compression tools

  • Try to unify the usage of the compression tools, where possible / necessary:
    • unified command line parsing
    • (Semi-)automatically provide showhelp function
  • Modify encodeAudio to accept "input streams", so that we can avoid creating temporary WAVE files
  • Easier usage: Most users will just want to specify the format, and maybe a "quality" setting. Allow power users to specify more advanced stuff, but only show those advance things when "--help" is requested, not in the basic "showUsage" function
  • Improved error checking !!! esp. for FT we got several reports about problems caused by the compression tool being called from the wrong directory. This should be avoidable by implementing suitable checks.
  • Improve and polish the GUI code we got from GSoC 2007 code
  • Funky long-term idea:
    • turn the tools into libraries (or "one" library)
    • current compression tools then just become thin wrappers around these
    • makes it much easier to write 3rd party (GUI?) compression tools
    • or even an official cross platform GUI (wxWindow? Java? ... )

Descumm

  • Turn it into a library, to be used by a command line frontend (like now), ScummVM debugger, and ScummEX. Basically, the API could consist of a single function, which takes a pointer to a memory buffer, its length, the Scumm version and optionally a game id. Also, it would get a pointer to a print function (in the case of the CLI tool, print to stdout; for ScummVM, print to our GUI console; for ScummEX, append to some window/widget)
  • Rewrite code to use 2 passes; first pass builds an intermediate graph, the second pass then tries to detect loops, break/continue statements etc.
  • Proper implementation of o6_startObjectQuick decompilation (see comment in descumm6.c). May require rewrite of core program logic.
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