OpenTTD's known bugs Last updated: 2013-06-01 Release version: 1.3.1 ------------------------------------------------------------------------ Table of contents ----------------- 1.0) About 2.0) Known bugs 1.0) About ---- ----- All bugs listed below are marked as known. Please do not submit any bugs that are the same as these. If you do, do not act surprised, because we WILL flame you!! The current list of known bugs that we intend to fix can be found in our bug tracking system at: http://bugs.openttd.org Also check the closed bugs when searching for your bug in this system as we might have fixed the bug in the mean time. 2.0) Known bugs ---- ---------------------------------- This section lists all known bugs that we do not intend to fix and the reasons why we think that fixing them is infeasible. We might make some minor improvements that reduce the scope of these bugs, but we will not be able to completely fix them. No suitable AI can be found If you have no AIs and an AI is started the so-called 'dummy' AI will be loaded. This AI does nothing but writing a message on the AI debug window and showing a red warning. There are basically two solutions for this problem: you must change the settings so no AI is started, this is done in the difficulty settings window. The other solution is acquiring (downloading) some AI. The easiest way to do this is via the "Check Online Content" button in the main (intro) menu or via "AI Settings" -> "Select AI" -> "Check Online Content" which is also accessed via the main menu. After a while of playing, colours get corrupted In Windows 7 the background slideshow corrupts the colour mapping of OpenTTD's 8bpp screen modes. Workarounds for this are: a) Switching to windowed mode, instead of fullscreen b) Switching off background slideshow c) Setting up the 32bpp-anim or 32bpp-optimized blitter Long delay between switching songs/music On Windows there is a delay of a (few) second(s) between switching of songs for the "win32" driver. This delay is caused by the fact that opening a MIDI file via MCI is extremely slow. DirectMusic, known as "dmusic" in OpenTTD, has a much shorter delay. However, under some circumstances DirectMusic does not reset its state properly causing wrongly pitched/bad sounding songs. This problem is in DirectMusic as it is reproducable with Microsoft's DirectMusic Producer. DirectMusic has been deprecated since 2004 and as such has no support for 64 bits OpenTTD. As a delay is favourable over bad sounding music the "win32" driver is the default driver for OpenTTD. You can change this default by setting the "musicdriver" in your openttd.cfg to "dmusic". Custom vehicle type name is incorrectly aligned Some NewGRFs use sprites that are bigger than normal in the "buy vehicle" window. Due to this they have to encode an offset for the vehicle type name. Upon renaming the vehicle type this encoded offset is stripped from the name because the "edit box" cannot show this encoding. As a result the custom vehicle type names will get the default alignment. The only way to (partly) fix this is by adding spaces to the custom name. Clipping problems [FS#119] In some cases sprites are not drawn as one would expect. Examples of this are aircraft that might be hidden below the runway or trees that in some cases are rendered over vehicles. The primary cause of this problem is that OpenTTD does not have enough data (like a 3D model) to properly determine what needs to be drawn in front of what. OpenTTD has bounding boxes but in lots of cases they are either too big or too small and then cause problems with what needs to be drawn in front of what. Also some visual tricks are used. For example trains at 8 pixels high, the catenary needs to be drawn above that. When you want to draw bridges on top of that, which are only one height level (= 8 pixels) higher, you are getting into some big problems. We can not change the height levels; it would require us to either redraw all vehicle or all landscape graphics. Doing so would mean we leave the Transport Tycoon graphics, which in effect means OpenTTD will not be a Transport Tycoon clone anymore. Mouse scrolling not possible at the edges of the screen [FS#383] [FS#3966] Scrolling the viewport with the mouse cursor at the edges of the screen in the same direction of the edge will fail. If the cursor is near the edge the scrolling will be very slow. OpenTTD only receives cursor position updates when the cursor is inside OpenTTD's window. It is not told how far you have moved the cursor outside of OpenTTD's window. Lost trains ignore (block) exit signals [FS#1473] If trains are lost they ignore block exit signals, blocking junctions with presignals. This is caused because the path finders cannot tell where the train needs to go. As such a random direction is chosen at each junction. This causes the trains to occasionally to make choices that are unwanted from a player's point of view. This will not be fixed because lost trains are in almost all cases a network problem, e.g. a train can never reach a specific place. This makes the impact of fixing the bug enormously small against the amount of work needed to write a system that prevents the lost trains from taking the wrong direction. Vehicle owner of last transfer leg gets paid for all [FS#2427] When you make a transfer system that switches vehicle owners. This is only possible with 'industry stations', e.g. the oil rig station the owner of the vehicle that does the final delivery gets paid for the whole trip. It is not shared amongst the different vehicle owners that have participated in transporting the cargo. This sharing is not done because it would enormously increase the memory and CPU usage in big games for something that is happening in only one corner case. We think it is not worth the effort until sharing of stations is an official feature. Forbid 90 degree turns does not work for crossing PBS paths [FS#2737] When you run a train through itself on a X junction with PBS turned on the train will not obey the 'forbid 90 degree turns' setting. This is due to the fact that we can not be sure that the setting was turned off when the track was reserved, which means that we assume it was turned on and that the setting does not hold at the time. We made it this way to allow one to change the setting in-game, but it breaks slightly when you are running your train through itself. Running a train through means that your network is broken and is thus a user error which OpenTTD tries to graciously handle. Fixing this bug means that we need to record whether this particular setting was turned on or off at the time the reservation was made. This means adding quite a bit of data to the savegame for solving an issue that is basically an user error. We think it is not worth the effort. Duplicate (station) names after renaming [FS#3204] After renaming stations one can create duplicate station names. This is done giving a station the same custom name as another station with an automatically generated name. The major part of this problem is that station names are translatable. Meaning that a station is called e.g. ' Central' in English and ' Centraal' in Dutch. This means that in network games the renaming of a town could cause the rename to succeed on some clients and fail at others. This creates an inconsistent game state that will be seen as a 'desync'. Secondly the custom names are intended to fall completely outside of the ' ' naming of stations, so when you rename a town all station names are updated accordingly. As a result the decision has been made that all custom names are only compared to the other custom names in the same class and not compared to the automatically generated names. Extreme CPU usage/hangs when using SDL and PulseAudio [FS#3294] OpenTTD hangs/freezes when closing, OpenTTD is slow, OpenTTD uses a lot of CPU OpenTTD can be extremely slow/use a lot of CPU when the sound is played via SDL and then through PulseAudio's ALSA wrapper. Under the same configuration OpenTTD, or rather SDL, might hang when exiting the game. This problem is seen most in Ubuntu 9.04 and higher. This is because recent versions of the PulseAudio sound server are configured to use timer-based audio scheduling rather than interrupt-based audio scheduling. Configuring PulseAudio to force use of interrupt-based scheduling may resolve sound problems for some users. Under recent versions of Ubuntu Linux (9.04 and higher) this can be accomplished by changing the following line in the /etc/pulse/default.pa file: load-module module-udev-detect to load-module module-udev-detect tsched=0 Note that PulseAudio must be restarted for changes to take effect. Older versions of PulseAudio may use the module-hal-detect module instead. Adding tsched=0 to the end of that line will have a similar effect. Another possible solution is selecting the "pulse" backend of SDL by either using "SDL_AUDIODRIVER=pulse openttd" at the command prompt or installing the 'libsdl1.2debian-pulseaudio' package from Ubuntu's Universe repository. For other distributions a similar package needs to be installed. OpenTTD not properly resizing with SDL on X [FS#3305] Under some X window managers OpenTTD's window does not properly resize. You will either end up with a black bar at the right/bottom side of the window or you cannot see the right/bottom of the window, e.g you cannot see the status bar. The problem is that OpenTTD does not always receive a resize event from SDL making it impossible for OpenTTD to know that the window was resized; sometimes moving the window will solve the problem. Window managers that are known to exhibit this behaviour are KDE's and GNOME's. With the XFCE's and LXDE's window managers the resize event is sent when the user releases the mouse. Incorrect colours, crashes upon exit, debug warnings and smears upon window resizing with SDL on Mac OS X [FS#3447] Video handling with (lib)SDL under Mac OS X is known to fail on some versions of Mac OS X with some hardware configurations. Some of the problems happen only under some circumstances whereas others are always present. We suggest that the SDL video/sound backend is not used for OpenTTD in combinations with Mac OS X. Train crashes entering same junction from block and path signals [FS#3928] When a train has reserved a path from a path signal to a two way block signal and the reservation passes a path signal through the back another train can enter the reserved path (only) via that same two way block signal. The reason for this has to do with optimisation; to fix this issue the signal update has to pass all path signals until it finds either a train or a backwards facing signal. This is a very expensive task. The (signal) setups that allow these crashes can furthermore be considered incorrectly signalled; one extra safe waiting point for the train entering from path signal just after the backwards facing signal (from the path signal train) resolves the issue. Crashes when playing music [FS#3941] Mac OS X's QuickTime (default music driver) and Windows' MCI (win32 music driver) crash on some songs from OpenMSX. OpenTTD cannot do anything about this. Please report these crashes to the authors of OpenMSX so the crash causing songs can be removed or fixed. Crashes when run in a VM using Parallels Desktop [FS#4003] When the Windows version of OpenTTD is executed in a VM under Parallels Desktop a privileged instruction exception may be thrown. As OpenTTD works natively on OSX as well as natively on Windows and these native builds both don't exhibit this behaviour this crash is most likely due to a bug in the virtual machine, something out of the scope of OpenTTD. Most likely this is due to Parallels Desktop lacking support for RDTSC calls. The problem can be avoided by using other VM-software, Wine, or running natively on OSX. OpenTTD hangs when started on 32 bits Windows [FS#4083] Under some circumstances OpenTTD might hang for hours on the initialisation of the music driver. The exact circumstances are unknown except that it is the "dmusic" music driver that has the problem and that the "win32" music driver does not. As a result using the "win32" music driver will work around this issue. As the exact circumstances are unknown, and the obvious configuration settings related to the music driver are at their default we are not able to detect this failure, except when Windows' music initialisation function returns after several hours and then there is no point in switching the music driver anymore. The reason we still use the "win32" music driver as default are described in the "Long delay between switching music/song" section of this document. Pre- and exit signals are not dragged [FS#4378] Unlike all other signal types, the entry- and exit signals are not dragged but instead normal signals are placed on subsequent track sections. This is done on purpose as this is the usually more con- venient solution. There are little to no occasions where more than one entry or exit signal in a row are useful. This is different for all other signal types where several in a row can serve one purpose or another. Station build date is incorrect [FS#4415] The tile query tool will show the date of the last (re)construction at the station and not the date of the first construction. This is due to compatability reasons with NewGRFs and the fact that it is wrong to say that the station is built in a particular year when it was completely destroyed/rebuilt later on. The tile query tool can be fixed by changing the "Build date" text to "Date at which the last (re)construction took place" but this is deemed too specific and long for that window. Can't change volume inside OpenTTD [FS#4416] Some backends do not provide a means to change the volume of sound effects or music. The mixing of music and sound is left to external libraries/the operating system we can't handle the volume control in OpenTTD. As a result you can't change the volume inside OpenTTD for backends such as SDL; just use the volume control provided by your operating system. Can't run OpenTTD with the -d option from a MSYS console [FS#4587] The MSYS console does not allow OpenTTD to open an extra console for debugging output. Compiling OpenTTD with the --enable-console configure option prevents this issue and allows the -d option to use the MSYS console for its output. Unreadable characters for non-latin locales [FS#4607] OpenTTD does not ship a non-latin font in its graphics files. As a result OpenTTD needs to acquire the font from somewhere else. What OpenTTD does is ask the operating system, or a system library, for the best font for a given language if the currently loaded font does not provide all characters of the chosen translation. This means that OpenTTD has no influence over the quality of the chosen font; it just does the best it can do. If the text is unreadable there are several steps that you can take to improve this. The first step is finding a good font and configure this in the configuration file. See section 9.0 of readme.txt for more information. You can also increase the font size to make the characters bigger and possible better readable. If the problem is with the clarity of the font you might want to enable anti-aliasing by setting the small_aa/medium_aa/large_aa settings to "true". However, anti-aliasing only works when a 32 bits blitter has been selected, e.g. blitter = "32bpp-anim", as with the 8 bits blitter there are not enough colours to properly perform the anti-aliasing. (Temporary) wrong colours when switching to full screen [FS#4511]: On Windows it can happen that you temporarily see wrong colours when switching to full screen OpenTTD, either by starting OpenTTD in full screen mode, changing to full screen mode or by ALT-TAB-ing into a full screen OpenTTD. This is caused by the fact that OpenTTD, by default, uses 8bpp paletted output. The wrong colours you are seeing is a temporary effect of the video driver switching to 8bpp palette mode. This issue can be worked around in two ways: a) Setting fullscreen_bpp to 32 b) Setting up the 32bpp-anim or 32bpp-optimized blitter Train does not crash with itself [FS#4635]: When a train drives in a circle the front engine passes through wagons of the same train without crashing. This is intentional. Signals are only aware of tracks, they do not consider the train length and whether there would be enough room for a train in some circle it might drive on. Also the path a train might take is not necessarily known when passing a signal. Checking all circumstances would take a lot of additional computational power for signals, which is not considered worth the effort, as it does not add anything to gameplay. Nevertheless trains shall not crash in normal operation, so making a train not crash with itself is the best solution for everyone. Aircraft coming through wall in rotated airports [FS#4705]: With rotated airports, specifically hangars, you will see that the aircraft will show a part through the back wall of the hangar. This can be solved by only drawing a part of the plane when being at the back of the hangar, however then with transparency turned on the aircraft would be shown partially which would be even weirder. As such the current behaviour is deemed the least bad. The same applies to overly long ships and their depots. Vehicles not keeping their "maximum" speed [FS#4815]: Vehicles that have not enough power to reach and maintain their advertised maximum speed might be constantly jumping between two speeds. This is due to the fact that speed and its calculations are done with integral numbers instead of floating point numbers. As a result of this a vehicle will never reach its equilibrium between the drag/friction and propulsion. So in effect it will be in a vicious circle of speeding up and slowing down due to being just at the other side of the equilibrium. Not speeding up when near the equilibrium will cause the vehicle to never come in the neighbourhood of the equilibrium and not slowing down when near the equilibrium will cause the vehicle to never slow down towards the equilibrium once it has come down a hill. It is possible to calculate whether the equilibrium will be passed, but then all acceleration calculations need to be done twice. Settings not saved when OpenTTD crashes [FS#4846]: The settings are not saved when OpenTTD crashes for several reasons. The most important is that the game state is broken and as such the settings might contain invalid values, or the settings have not even been loaded yet. This would cause invalid or totally wrong settings to be written to the configuration file. A solution to that would be saving the settings whenever one changes, however due to the way the configuration file is saved this requires a flush of the file to the disk and OpenTTD needs to wait till that is finished. On some file system implementations this causes the flush of all 'write-dirty' caches, which can be a significant amount of data to be written. This can further be aggravated by spinning down disks to conserve power, in which case this disk needs to be spun up first. This means that many seconds may pass before the configuration file is actually written, and all that time OpenTTD will not be able to show any progress. Changing the way the configuration file is saved is not an option as that leaves us more vulnerable to corrupt configuration files. Finally, crashes should not be happening. If they happen they should be reported and fixed, so essentially fixing this is fixing the wrong thing. If you really need the configuration changes to be saved, and you need to run a version that crashes regularly, then you can use the 'saveconfig' command in the console to save the settings. Not all NewGRFs, AIs, game scripts are found [FS#4887]: Under certain situations, where the path for the content within a tar file is the same as other content on the file system or in another tar file, it is possible that content is not found. A more thorough explanation and solutions are described in section 4.4 of readme.txt. Mouse cursor going missing with SDL [FS#4997]: Under certain circumstances SDL does not notify OpenTTD of changes with respect to the mouse pointer, specifically whether the mouse pointer is within the bounds of OpenTTD or not. For example, if you Alt-tab to another application the mouse cursor will still be shown in OpenTTD, and when you move the mouse outside of the OpenTTD window so the cursor gets hidden, open/move another application on top of the OpenTTD window and then Alt-tab back into OpenTTD the cursor will not be shown. We cannot fix this problem as SDL simply does not provide the required information in these corner cases. This is a bug in SDL and as such there is little that we can do about it. Inconsistent catchment areas [FS#5661]: Due to performance decisions the catchment area for cargo accepted by a station for delivery to houses or industries differs from the catchment area for cargo that is delivered to stations from houses or industries. Conceptually they work the same, but the effect in game differs. They work by finding the closest destination "around" the source which is within a certain distance. This distance depends on the type of station, e.g. road stops have a smaller catchment area than large airports. In both cases the bounding box, the smallest rectangle that contains all tiles of something, is searched for the target of the cargo, and then spiraling outwards finding the closest tile of the target. In the case of a station with two tiles spread far apart with a house that is within the station's bounding box, it would be possible that the spiraling search from the house does not reach one of the station tiles before the search ends, i.e. all tiles within that distance are searched. So the house does not deliver cargo to the station. On the other hand, the station will deliver cargo because the house falls within the bounding box, and thus search area. It is possible to make these consistent, but then cargo from a house to a station needs to search up to 32 tiles around itself, i.e. 64 by 64 tiles, to find all possible stations it could deliver to instead of 10 by 10 tiles (40 times more tiles). Alternatively the search from a station could be changed to use the actual tiles, but that would require considering checking 10 by 10 tiles for each of the tiles of a station, instead of just once.