S1 of the station: it exists, it orbits, it wraps, it is drawn. Docking
is deliberately not here - the point of stopping at this rung is to fly
up and find out whether matching a four pixel a frame target feels good
before any rules are written about what happens when you reach it.
IT NEEDS NO PHYSICS OF ITS OWN. A body at 64 sixteenths is exactly what
a circular orbit is under the rules already here: the pull and the swing
cancel at that speed at ANY height, because gravity never falls off and
the moon is a cylinder that does not rotate. So the station is a
position, a constant, and the same fourteen bit wrap the lander uses.
That also means there is no prograde or retrograde to choose - nothing
privileges a direction, which is what makes a second station going the
other way a thing that can exist later.
Four rows above the world's origin: off the top of a forty column screen
and comfortably inside a wide one, so it is somewhere to go that the zoom
is needed to see. It starts half a moon away and a lap is 256 frames, a
little over four seconds, so it has to be found but will not stay lost.
Its column is the middle of the screen plus how far round it is from the
lander, wrapped to fourteen bits - which measures the long way round
whenever it is behind, so anything past the half way point becomes a
negative offset instead. Off the edge needs no test at all: a sprite's X
is signed and sixteen bits, so a station three hundred pixels to the left
is asked for at minus a hundred and forty and the device declines.
Blue, and that is not taste. White is counted to find the ceiling
warning, cyan to find the landing pads, magenta is the instruments and
yellow is the lander. Blue is the one ink no check measures, and picking
a measured one has broken a test twice already.
toPixelsSigned is factored out of showLander, since the station wants the
same sign-extended conversion.
Four checks, each seen to fail on its own break. Measured going round at
244 pixels in sixty frames, off the far side of the moon, and back on the
other edge.
Anachronaut
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