With BUFFER_LONG = 1, refetch fires every ~1 tile of motion (every
~8 sec at default speed). With BUFFER = 1 the center shifts by
~1 tile per refetch, so only ~1 net new tile needs fetching each
time (the one at the very front of the new corridor).
Switch to partial refetch:
- Don't clear the canvas before redrawing
- Skip tiles already in groundLoadedTiles (they're still on the
canvas at the right position from a prior refetch)
- Only newly-positioned tiles are drawn (the ones in the new
front of the corridor, ahead in flight direction)
Effect: user sees tiles appearing at the front of the corridor in
the direction of travel, not the whole canvas flashing every 8 sec.
With N flight, fetch activity shows up at the top of the screen
(where lng=+12 lands after the axis swap), confirming the flight
direction is correct.
Richard Zink
4cf3c00dfa