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1 OpenTTD's known bugs
2 Last updated: 2013-06-01
3 Release version: 1.3.1
4 ------------------------------------------------------------------------
7 Table of contents
8 -----------------
9 1.0) About
10 2.0) Known bugs
13 1.0) About
14 ---- -----
15 All bugs listed below are marked as known. Please do not submit any bugs
16 that are the same as these. If you do, do not act surprised, because
17 we WILL flame you!!
19 The current list of known bugs that we intend to fix can be found in our
20 bug tracking system at: http://bugs.openttd.org
21 Also check the closed bugs when searching for your bug in this system as
22 we might have fixed the bug in the mean time.
25 2.0) Known bugs
26 ---- ----------------------------------
27 This section lists all known bugs that we do not intend to fix and the
28 reasons why we think that fixing them is infeasible. We might make some
29 minor improvements that reduce the scope of these bugs, but we will not
30 be able to completely fix them.
32 No suitable AI can be found
33 If you have no AIs and an AI is started the so-called 'dummy' AI will
34 be loaded. This AI does nothing but writing a message on the AI debug
35 window and showing a red warning. There are basically two solutions
36 for this problem: you must change the settings so no AI is started,
37 this is done in the difficulty settings window. The other solution is
38 acquiring (downloading) some AI. The easiest way to do this is via
39 the "Check Online Content" button in the main (intro) menu or via
40 "AI Settings" -> "Select AI" -> "Check Online Content" which is also
41 accessed via the main menu.
43 After a while of playing, colours get corrupted
44 In Windows 7 the background slideshow corrupts the colour mapping of
45 OpenTTD's 8bpp screen modes. Workarounds for this are:
46 a) Switching to windowed mode, instead of fullscreen
47 b) Switching off background slideshow
48 c) Setting up the 32bpp-anim or 32bpp-optimized blitter
50 Long delay between switching songs/music
51 On Windows there is a delay of a (few) second(s) between switching of
52 songs for the "win32" driver. This delay is caused by the fact that
53 opening a MIDI file via MCI is extremely slow.
55 DirectMusic, known as "dmusic" in OpenTTD, has a much shorter delay.
56 However, under some circumstances DirectMusic does not reset its
57 state properly causing wrongly pitched/bad sounding songs. This
58 problem is in DirectMusic as it is reproducable with Microsoft's
59 DirectMusic Producer. DirectMusic has been deprecated since 2004
60 and as such has no support for 64 bits OpenTTD.
62 As a delay is favourable over bad sounding music the "win32" driver
63 is the default driver for OpenTTD. You can change this default by
64 setting the "musicdriver" in your openttd.cfg to "dmusic".
66 Custom vehicle type name is incorrectly aligned
67 Some NewGRFs use sprites that are bigger than normal in the "buy
68 vehicle" window. Due to this they have to encode an offset for the
69 vehicle type name. Upon renaming the vehicle type this encoded offset
70 is stripped from the name because the "edit box" cannot show this
71 encoding. As a result the custom vehicle type names will get the
72 default alignment. The only way to (partly) fix this is by adding
73 spaces to the custom name.
75 Clipping problems [FS#119]
76 In some cases sprites are not drawn as one would expect. Examples of
77 this are aircraft that might be hidden below the runway or trees that
78 in some cases are rendered over vehicles.
79 The primary cause of this problem is that OpenTTD does not have enough
80 data (like a 3D model) to properly determine what needs to be drawn in
81 front of what. OpenTTD has bounding boxes but in lots of cases they
82 are either too big or too small and then cause problems with what
83 needs to be drawn in front of what. Also some visual tricks are used.
84 For example trains at 8 pixels high, the catenary needs to be drawn
85 above that. When you want to draw bridges on top of that, which are
86 only one height level (= 8 pixels) higher, you are getting into some
87 big problems.
88 We can not change the height levels; it would require us to either
89 redraw all vehicle or all landscape graphics. Doing so would mean we
90 leave the Transport Tycoon graphics, which in effect means OpenTTD
91 will not be a Transport Tycoon clone anymore.
93 Mouse scrolling not possible at the edges of the screen [FS#383] [FS#3966]
94 Scrolling the viewport with the mouse cursor at the edges of the screen
95 in the same direction of the edge will fail. If the cursor is near the
96 edge the scrolling will be very slow.
97 OpenTTD only receives cursor position updates when the cursor is inside
98 OpenTTD's window. It is not told how far you have moved the cursor
99 outside of OpenTTD's window.
101 Lost trains ignore (block) exit signals [FS#1473]
102 If trains are lost they ignore block exit signals, blocking junctions
103 with presignals. This is caused because the path finders cannot tell
104 where the train needs to go. As such a random direction is chosen at
105 each junction. This causes the trains to occasionally to make choices
106 that are unwanted from a player's point of view.
107 This will not be fixed because lost trains are in almost all cases a
108 network problem, e.g. a train can never reach a specific place. This
109 makes the impact of fixing the bug enormously small against the
110 amount of work needed to write a system that prevents the lost trains
111 from taking the wrong direction.
113 Vehicle owner of last transfer leg gets paid for all [FS#2427]
114 When you make a transfer system that switches vehicle owners. This
115 is only possible with 'industry stations', e.g. the oil rig station
116 the owner of the vehicle that does the final delivery gets paid for
117 the whole trip. It is not shared amongst the different vehicle
118 owners that have participated in transporting the cargo.
119 This sharing is not done because it would enormously increase the
120 memory and CPU usage in big games for something that is happening
121 in only one corner case. We think it is not worth the effort until
122 sharing of stations is an official feature.
124 Forbid 90 degree turns does not work for crossing PBS paths [FS#2737]
125 When you run a train through itself on a X junction with PBS turned on
126 the train will not obey the 'forbid 90 degree turns' setting. This is
127 due to the fact that we can not be sure that the setting was turned
128 off when the track was reserved, which means that we assume it was
129 turned on and that the setting does not hold at the time. We made it
130 this way to allow one to change the setting in-game, but it breaks
131 slightly when you are running your train through itself. Running a
132 train through means that your network is broken and is thus a user
133 error which OpenTTD tries to graciously handle.
134 Fixing this bug means that we need to record whether this particular
135 setting was turned on or off at the time the reservation was made. This
136 means adding quite a bit of data to the savegame for solving an issue
137 that is basically an user error. We think it is not worth the effort.
139 Duplicate (station) names after renaming [FS#3204]
140 After renaming stations one can create duplicate station names. This
141 is done giving a station the same custom name as another station with
142 an automatically generated name.
143 The major part of this problem is that station names are translatable.
144 Meaning that a station is called e.g. '<TOWN> Central' in English and
145 '<TOWN> Centraal' in Dutch. This means that in network games the
146 renaming of a town could cause the rename to succeed on some clients
147 and fail at others. This creates an inconsistent game state that will
148 be seen as a 'desync'. Secondly the custom names are intended to fall
149 completely outside of the '<TOWN> <name>' naming of stations, so when
150 you rename a town all station names are updated accordingly.
151 As a result the decision has been made that all custom names are only
152 compared to the other custom names in the same class and not compared
153 to the automatically generated names.
155 Extreme CPU usage/hangs when using SDL and PulseAudio [FS#3294]
156 OpenTTD hangs/freezes when closing, OpenTTD is slow, OpenTTD uses a lot of CPU
157 OpenTTD can be extremely slow/use a lot of CPU when the sound is
158 played via SDL and then through PulseAudio's ALSA wrapper. Under the
159 same configuration OpenTTD, or rather SDL, might hang when exiting
160 the game. This problem is seen most in Ubuntu 9.04 and higher.
162 This is because recent versions of the PulseAudio sound server are
163 configured to use timer-based audio scheduling rather than
164 interrupt-based audio scheduling. Configuring PulseAudio to force
165 use of interrupt-based scheduling may resolve sound problems for
166 some users. Under recent versions of Ubuntu Linux (9.04 and higher)
167 this can be accomplished by changing the following line in the
168 /etc/pulse/default.pa file:
169 load-module module-udev-detect
170 to
171 load-module module-udev-detect tsched=0
172 Note that PulseAudio must be restarted for changes to take effect.
173 Older versions of PulseAudio may use the module-hal-detect module
174 instead. Adding tsched=0 to the end of that line will have a similar
175 effect.
177 Another possible solution is selecting the "pulse" backend of SDL
178 by either using "SDL_AUDIODRIVER=pulse openttd" at the command
179 prompt or installing the 'libsdl1.2debian-pulseaudio' package from
180 Ubuntu's Universe repository. For other distributions a similar
181 package needs to be installed.
183 OpenTTD not properly resizing with SDL on X [FS#3305]
184 Under some X window managers OpenTTD's window does not properly
185 resize. You will either end up with a black bar at the right/bottom
186 side of the window or you cannot see the right/bottom of the window,
187 e.g you cannot see the status bar. The problem is that OpenTTD does
188 not always receive a resize event from SDL making it impossible for
189 OpenTTD to know that the window was resized; sometimes moving the
190 window will solve the problem.
191 Window managers that are known to exhibit this behaviour are KDE's
192 and GNOME's. With the XFCE's and LXDE's window managers the resize
193 event is sent when the user releases the mouse.
195 Incorrect colours, crashes upon exit, debug warnings and smears upon
196 window resizing with SDL on Mac OS X [FS#3447]
197 Video handling with (lib)SDL under Mac OS X is known to fail on some
198 versions of Mac OS X with some hardware configurations. Some of the
199 problems happen only under some circumstances whereas others are
200 always present.
201 We suggest that the SDL video/sound backend is not used for OpenTTD
202 in combinations with Mac OS X.
204 Train crashes entering same junction from block and path signals [FS#3928]
205 When a train has reserved a path from a path signal to a two way
206 block signal and the reservation passes a path signal through the
207 back another train can enter the reserved path (only) via that same
208 two way block signal.
209 The reason for this has to do with optimisation; to fix this issue
210 the signal update has to pass all path signals until it finds either
211 a train or a backwards facing signal. This is a very expensive task.
212 The (signal) setups that allow these crashes can furthermore be
213 considered incorrectly signalled; one extra safe waiting point for
214 the train entering from path signal just after the backwards facing
215 signal (from the path signal train) resolves the issue.
217 Crashes when playing music [FS#3941]
218 Mac OS X's QuickTime (default music driver) and Windows' MCI (win32
219 music driver) crash on some songs from OpenMSX. OpenTTD cannot do
220 anything about this. Please report these crashes to the authors of
221 OpenMSX so the crash causing songs can be removed or fixed.
223 Crashes when run in a VM using Parallels Desktop [FS#4003]
224 When the Windows version of OpenTTD is executed in a VM under
225 Parallels Desktop a privileged instruction exception may be thrown.
226 As OpenTTD works natively on OSX as well as natively on Windows and
227 these native builds both don't exhibit this behaviour this crash is
228 most likely due to a bug in the virtual machine, something out of
229 the scope of OpenTTD. Most likely this is due to Parallels Desktop
230 lacking support for RDTSC calls. The problem can be avoided by using
231 other VM-software, Wine, or running natively on OSX.
233 OpenTTD hangs when started on 32 bits Windows [FS#4083]
234 Under some circumstances OpenTTD might hang for hours on the
235 initialisation of the music driver. The exact circumstances are
236 unknown except that it is the "dmusic" music driver that has the
237 problem and that the "win32" music driver does not.
238 As a result using the "win32" music driver will work around this
239 issue.
241 As the exact circumstances are unknown, and the obvious
242 configuration settings related to the music driver are at their
243 default we are not able to detect this failure, except when Windows'
244 music initialisation function returns after several hours and then
245 there is no point in switching the music driver anymore.
246 The reason we still use the "win32" music driver as default are
247 described in the "Long delay between switching music/song" section
248 of this document.
250 Pre- and exit signals are not dragged [FS#4378]
251 Unlike all other signal types, the entry- and exit signals are not
252 dragged but instead normal signals are placed on subsequent track
253 sections. This is done on purpose as this is the usually more con-
254 venient solution. There are little to no occasions where more than
255 one entry or exit signal in a row are useful. This is different
256 for all other signal types where several in a row can serve one
257 purpose or another.
259 Station build date is incorrect [FS#4415]
260 The tile query tool will show the date of the last (re)construction
261 at the station and not the date of the first construction. This is
262 due to compatability reasons with NewGRFs and the fact that it is
263 wrong to say that the station is built in a particular year when it
264 was completely destroyed/rebuilt later on.
265 The tile query tool can be fixed by changing the "Build date" text
266 to "Date at which the last (re)construction took place" but this is
267 deemed too specific and long for that window.
269 Can't change volume inside OpenTTD [FS#4416]
270 Some backends do not provide a means to change the volume of sound
271 effects or music. The mixing of music and sound is left to external
272 libraries/the operating system we can't handle the volume control
273 in OpenTTD. As a result you can't change the volume inside OpenTTD
274 for backends such as SDL; just use the volume control provided by
275 your operating system.
277 Can't run OpenTTD with the -d option from a MSYS console [FS#4587]
278 The MSYS console does not allow OpenTTD to open an extra console for
279 debugging output. Compiling OpenTTD with the --enable-console
280 configure option prevents this issue and allows the -d option to use
281 the MSYS console for its output.
283 Unreadable characters for non-latin locales [FS#4607]
284 OpenTTD does not ship a non-latin font in its graphics files. As a
285 result OpenTTD needs to acquire the font from somewhere else. What
286 OpenTTD does is ask the operating system, or a system library, for
287 the best font for a given language if the currently loaded font
288 does not provide all characters of the chosen translation. This
289 means that OpenTTD has no influence over the quality of the chosen
290 font; it just does the best it can do.
292 If the text is unreadable there are several steps that you can take
293 to improve this. The first step is finding a good font and configure
294 this in the configuration file. See section 9.0 of readme.txt for
295 more information. You can also increase the font size to make the
296 characters bigger and possible better readable.
298 If the problem is with the clarity of the font you might want to
299 enable anti-aliasing by setting the small_aa/medium_aa/large_aa
300 settings to "true". However, anti-aliasing only works when a 32 bits
301 blitter has been selected, e.g. blitter = "32bpp-anim", as with the
302 8 bits blitter there are not enough colours to properly perform the
303 anti-aliasing.
305 (Temporary) wrong colours when switching to full screen [FS#4511]:
306 On Windows it can happen that you temporarily see wrong colours
307 when switching to full screen OpenTTD, either by starting
308 OpenTTD in full screen mode, changing to full screen mode or by
309 ALT-TAB-ing into a full screen OpenTTD. This is caused by the
310 fact that OpenTTD, by default, uses 8bpp paletted output. The
311 wrong colours you are seeing is a temporary effect of the video
312 driver switching to 8bpp palette mode.
314 This issue can be worked around in two ways:
315 a) Setting fullscreen_bpp to 32
316 b) Setting up the 32bpp-anim or 32bpp-optimized blitter
318 Train does not crash with itself [FS#4635]:
319 When a train drives in a circle the front engine passes through
320 wagons of the same train without crashing. This is intentional.
321 Signals are only aware of tracks, they do not consider the train
322 length and whether there would be enough room for a train in some
323 circle it might drive on. Also the path a train might take is not
324 necessarily known when passing a signal.
325 Checking all circumstances would take a lot of additional computational
326 power for signals, which is not considered worth the effort, as
327 it does not add anything to gameplay.
328 Nevertheless trains shall not crash in normal operation, so making
329 a train not crash with itself is the best solution for everyone.
331 Aircraft coming through wall in rotated airports [FS#4705]:
332 With rotated airports, specifically hangars, you will see that the
333 aircraft will show a part through the back wall of the hangar.
334 This can be solved by only drawing a part of the plane when being
335 at the back of the hangar, however then with transparency turned on
336 the aircraft would be shown partially which would be even weirder.
337 As such the current behaviour is deemed the least bad.
338 The same applies to overly long ships and their depots.
340 Vehicles not keeping their "maximum" speed [FS#4815]:
341 Vehicles that have not enough power to reach and maintain their
342 advertised maximum speed might be constantly jumping between two
343 speeds. This is due to the fact that speed and its calculations
344 are done with integral numbers instead of floating point numbers.
345 As a result of this a vehicle will never reach its equilibrium
346 between the drag/friction and propulsion. So in effect it will be
347 in a vicious circle of speeding up and slowing down due to being
348 just at the other side of the equilibrium.
350 Not speeding up when near the equilibrium will cause the vehicle
351 to never come in the neighbourhood of the equilibrium and not
352 slowing down when near the equilibrium will cause the vehicle
353 to never slow down towards the equilibrium once it has come down
354 a hill.
356 It is possible to calculate whether the equilibrium will be
357 passed, but then all acceleration calculations need to be done
358 twice.
360 Settings not saved when OpenTTD crashes [FS#4846]:
361 The settings are not saved when OpenTTD crashes for several reasons.
362 The most important is that the game state is broken and as such the
363 settings might contain invalid values, or the settings have not even
364 been loaded yet. This would cause invalid or totally wrong settings
365 to be written to the configuration file.
367 A solution to that would be saving the settings whenever one changes,
368 however due to the way the configuration file is saved this requires
369 a flush of the file to the disk and OpenTTD needs to wait till that
370 is finished. On some file system implementations this causes the
371 flush of all 'write-dirty' caches, which can be a significant amount
372 of data to be written. This can further be aggravated by spinning
373 down disks to conserve power, in which case this disk needs to be
374 spun up first. This means that many seconds may pass before the
375 configuration file is actually written, and all that time OpenTTD
376 will not be able to show any progress. Changing the way the
377 configuration file is saved is not an option as that leaves us more
378 vulnerable to corrupt configuration files.
380 Finally, crashes should not be happening. If they happen they should
381 be reported and fixed, so essentially fixing this is fixing the
382 wrong thing. If you really need the configuration changes to be
383 saved, and you need to run a version that crashes regularly, then
384 you can use the 'saveconfig' command in the console to save the
385 settings.
387 Not all NewGRFs, AIs, game scripts are found [FS#4887]:
388 Under certain situations, where the path for the content within a
389 tar file is the same as other content on the file system or in another
390 tar file, it is possible that content is not found. A more thorough
391 explanation and solutions are described in section 4.4 of readme.txt.
393 Mouse cursor going missing with SDL [FS#4997]:
394 Under certain circumstances SDL does not notify OpenTTD of changes
395 with respect to the mouse pointer, specifically whether the mouse
396 pointer is within the bounds of OpenTTD or not. For example, if you
397 Alt-tab to another application the mouse cursor will still be shown
398 in OpenTTD, and when you move the mouse outside of the OpenTTD
399 window so the cursor gets hidden, open/move another application on
400 top of the OpenTTD window and then Alt-tab back into OpenTTD the
401 cursor will not be shown.
403 We cannot fix this problem as SDL simply does not provide the
404 required information in these corner cases. This is a bug in SDL
405 and as such there is little that we can do about it.