# Frame per second
FPS = 30
-# Night length in ticks
+# Night length in ticks and hours
NIGHT_LENGTH = 1500
-# Night length in hours
NIGHT_LENGTH_HOURS = 12
+NIGHT_HOURS_PER_TICK = float(NIGHT_LENGTH_HOURS) / NIGHT_LENGTH
# Pymunk categories
OBSTACLE_CATEGORY = 1 << 0