OpenTTD's known bugs

Last updated:    2010-09-14

Release version: 1.0.4

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Table of Contents:

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1) About

2) Known bugs in the this stable release

3) Known bugs that will not be solved





1) 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!!



Of course if you have more knowledge about any of these bugs, have more

specifics, we welcome you to report them. React to the given bug indicated

by the number below on http://bugs.openttd.org.





2) Known bugs in the this stable release:

-- --------------------------------------

The following bugs are known to exist in this stable release and

we intend to fix them. Some bugs are known but are not fixable or

fixing them would cause further problems. Those bugs can be found

in the "Known bugs that will not be solved" section.



The bugs in this section all refer to a ticket in our bug tracking system

that you can find at: http://bugs.openttd.org

If the bugs are closed but still listed here it means that the bug is fixed

and that the nightlies and next major release will not have that bug.



Issues prefixed with [OSX] are required to be fixed before we consider

officially supporting Mac OS X again. For now it remains unsupported and

we only apply bug fixes provided by the community but we are unable to fix

these bugs ourselves.



- 4003	[OSX] Running OpenTTD Parallels causes privileged instructions

- 4001	[OSX] SETX[Y] not ignored in SetFallbackFont

- 3952	Console command rescan_ai does not remove AIs

- 3935	Under some circumstances two road vehicles can leave road stop simultaniously

- 3816	Console text does not always fit at 640x480

- 3746	Console output with right-to-left texts in left-to-right texts is not correct

- 3714	Some corrupted savegames can cause crashes

- 3651	[OSX] Crash when selecting full screen

- 3648	[OSX] Crash when selecting music

- 3637	Second highest competing station gets penalised twice

- 3546	Ignoring signals might crash trains

- 3447	[OSX] SDL port is unuseable

- 2782	[OSX] Port hopelessly outdated

- 2585	[OSX] OS' mouse pointer showing

- 2484	[OSX] Cannot enter CJK characters





3) Known bugs that will not be solved:

-- -----------------------------------

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. '<TOWN> Central' in English and

	'<TOWN> 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 '<TOWN> <name>' 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.



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.



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 do not use the "win32" music driver as default are

	described in the "Long delay between switching music/song" section

	of this document.

