R5759 crash during zooming on map with large maps

[jk271]

I have discovered bug on latest development version.
Latest development version (revision 5759) crashes on zooming in map with large maps.
To be more precise revision 5759 crashes but bug might have been introduced earlier as I have NOT done git bisect.

I am using 32bit GNU/Linux (Debian) on 32 bit computer.
My CPU (Core Duo T2400) has 2 cores so real parallelisation is possible there.


How to reproduce it:
I have started a new game with a large map (2048x2048 tiles).
I have build some transport lines. It can be done by AI. This step is necessary.
I have opened a map pressing key "m".
I have zoomed in on a map. When I reached ratio of 1:16, program crashed.

Following lines comes from command line program output and from backtrace command in gdb.

WARNING: image3840 w=0!
WARNING: image2105 w=0!
[New Thread 0xb1df4b70 (LWP 12179)]
WARNING: image5619 w=0!
WARNING: image5623 w=0!
FATAL ERROR: array2d_tpl<T>::at()
index out of bounds: (5280,32112) not in (0..-32769, 0..-32769)


Program received signal SIGABRT, Aborted.
0xb7fe2424 in __kernel_vsyscall ()
(gdb) bt
#0  0xb7fe2424 in __kernel_vsyscall ()
#1  0xb7c76781 in *__GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#2  0xb7c79bb2 in *__GI_abort () at abort.c:92
#3  0x0821ad6b in log_t::fatal(char const*, char const*, ...) ()
#4  0x0812ccbf in reliefkarte_t::set_relief_farbe(koord, int) ()
#5  0x0812d5d0 in reliefkarte_t::calc_map_pixel(koord) ()
#6  0x082264ab in vehikel_t::verlasse_feld() ()
#7  0x08229ef0 in vehikel_t::hop() ()
#8  0x0822567f in vehikel_basis_t::fahre_basis(unsigned int) ()
#9  0x081aadd2 in convoi_t::sync_step(long) ()
#10 0x0820a8c1 in karte_t::sync_step(long, bool, bool) ()
#11 0x081cd005 in interrupt_check(char const*) ()
#12 0x081cd034 in interrupt_check() ()
#13 0x0820b3e6 in karte_t::interactive(unsigned int) ()
#14 0x081d2c55 in simu_main(int, char**) ()
#15 0x081de0ed in sysmain(int, char**) ()
#16 0x0823de7a in main ()

[Dwachs]

Looks like integer over/underflow.

[Dwachs]

Should be fixed with r5673. You cannot zoom in that much on large maps now to prevent this crash from reappearing.

[jk271]

Thank you for fixing it.
I will test it when it reaches git repository. I came on it by accident because I usually do not zoom so much.

[jk271]

I have tested it today. It work well. No crash occured.
It can be moved to resolved now.