Grid the landscape, and shortcircuit checks on the collision array if there are no nearby checked in collisions to be collided with. This is a big win for fire's ammoshove in particular. Also add a +2 that seemed missing in the check, and update fire accordingly.
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# Automatically generated by qmake (2.01a) ?? 23. ??? 20:44:46 2007
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TEMPLATE = app
TARGET =
DEPENDPATH += .
INCLUDEPATH += .
# Input
HEADERS += mainform.h pixlabel.h
SOURCES += main.cpp mainform.cpp pixlabel.cpp