Program received signal SIGSEGV, Segmentation fault.
0x005f0f07 in d3dda ()
(gdb) bt
#0  0x005f0f07 in d3dda ()
#1  0x041cae88 in ?? ()
#2  0x005f4b13 in ray_shadow ()
#3  0x005fede3 in lamp_get_shadow ()
#4  0x005ffd91 in shade_lamp_loop ()
#5  0x005fa63d in shade_material_loop ()
#6  0x005faa6e in shade_input_do_shade ()
#7  0x005fd565 in shade_samples ()
#8  0x005d8c19 in zbufshadeDA_tile ()
#9  0x005c0171 in do_part_thread ()
#10 0x611812fa in ptw32_threadStart@4 ()
#11 0x77c3a3b0 in _libmsvcrt_a_iname ()
#12 0x7c80b683 in _libmsvcrt_a_iname ()
(gdb)