### - o -

- ObjectChangeInfo() : newgrf.cpp
- OffsetGroundSprite() : viewport.cpp , viewport_func.h
- OnNewDay() : date.cpp
- OnNewMonth() : date.cpp
- OnNewYear() : date.cpp
- OnTick_Companies() : landscape.cpp , company_cmd.cpp
- OPFShipChooseTrack() : opf_ship.cpp , opf_ship.h
- OppositeCorner() : slope_func.h
- OrderConditionCompare() : order_cmd.cpp
- OrderGoesToStation() : order_cmd.cpp
- OtherAxis() : direction_func.h
- OTTD2FS() : stdafx.h , win32.cpp
- ottd_mkdir() : strgen.cpp
- ottd_rdtsc() : os_timer.cpp , debug.h
- OTTDSHGetFolderPath() : win32.cpp , win32.h