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Docking, and a ceiling that is no longer the old screen's edge

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The station can be docked with: close enough, and slow enough RELATIVE TO
IT, or it is a wreck. Its speed is orbital speed, which is what the marks
on the drift bar point at, so the instrument for this was on the screen
before there was anything to dock with. A dock pays eighty units of fuel,
once and not once a frame, and holds the lander a tile under the station
until a thruster lets go - checked before the speeds are put back, or a
burn would be wiped on the frame it was made and the lander could never
leave.

---- And the ceiling went up, which is what made it work ----

Sixty four pixels was the whole of the sky a forty column screen had over
the world's origin. It was never a fact about the world, it was a fact
about the view, and the wide one starts twenty four rows higher: a lander
stopped at the old line was stopped a long way short of the top of its own
picture for no reason it could see. It is 192 pixels now, the top of the
wide view.

The station went from four rows up to twelve - about two thirds of the way
from the ground to the ceiling. At four it sat exactly where anything
climbing away from the surface had to pass, and being run down there is
not a hazard, it is a toll: ELEVEN of this suite's flights were being run
down as collateral, including the ceiling check, which has to climb past
it to reach the ceiling at all. Moving both fixed all eleven at once.

The height bar divides by sixty four rather than thirty two, because the
band it describes is 368 pixels now and half a pixel of bar to a pixel of
sky would stand 184 tall and run off the top of the forty column screen it
is drawn beside.

---- What is checked, and what is written down instead ----

The wreck is flown. The fixture is narrow - the window measured 496 to 514
frames of climb and it sits at 505 - and that is said in place, along with
the instruction to re-measure before believing the code is broken. It was
not always narrow: at the old altitude any climb from 135 to 300 frames
struck. Narrow is the right way round, because it means the station is
hard to blunder into.

The successful dock is NOT flown, and ninety six pad files failed to find
it. That is not the search's fault: climbing spends sideways speed, so a
lander cannot rise while matched. It is measured working instead - tank
100 to 180, message up, and the pair holding together one tile apart for
two hundred and forty frames.
This commit is contained in:
Anachronaut
2026-09-04 10:37:52 -04:00
parent 922511c8a7
commit 804dd3040e
13 changed files with 316 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Programs/CosmOS/Apps/Lander.asm
+258 -13
View File
@@ -103,6 +103,7 @@ everyFrame:
CALL moveStation
CALL follow
CALL touchdown
CALL dock
CALL showLander
CALL showStation
CALL showDrift
@@ -750,7 +751,10 @@ fall:
LDA.1
SETD.1 FallTick
STA.1
; Gravity does not pull on a lander that is already sitting on the ground.
; Gravity does not pull on a lander that is sitting on the ground or holding onto something.
SETD.0 Docked
LDA.0
BNA fallResting
SETD.0 Landed
LDA.0
BNA fallResting
@@ -1124,6 +1128,13 @@ move:
; kept going came back through the bottom and hit the ground FROM ABOVE. Two thousand pixels
; of climb is a long way and entirely reachable with a full tank.
;
; ---- And it is 192 pixels up, not 64, because the screen grew ----
;
; Sixty four was the whole of the sky a forty column screen had over the world's origin, so
; it was never a fact about the world - it was a fact about the view. The wide one starts
; twenty four rows higher, and a lander stopped at the old line was stopped a long way short
; of the top of its own picture for no reason it could see.
;
; Pinned rather than ended. Leaving upward is RECOVERABLE - gravity is always available and
; a lander with fuel can always come back - so stopping the run there would punish a state
; the player can fly out of. What kills you out here is running dry a long way from the
@@ -1139,10 +1150,10 @@ move:
AND
BRQ moveInside ; The height is positive, so it is somewhere below the top.
LDA.0 ; DP0 is still DownHigh, from the sign test.
INIB 0xFD
INIB 0xF5
CCF
SUB
BRC moveAdrift ; Borrowed: at 0xFC00 or above it, which is 64 pixels over the top.
BRC moveAdrift ; Borrowed: at 0xF400 or above it, 192 pixels over the world's top.
moveInside:
; Back under the ceiling, so the warning goes if there was one.
@@ -1161,7 +1172,7 @@ moveAdrift:
; is left alone, so gravity has somewhere to move it to.
SETD.0 DownHigh
LDA.0
INIB 0xFC
INIB 0xF4
CCF
SUB
BNC moveAdriftSaid ; No borrow, so it is at the ceiling and not past it.
@@ -1169,7 +1180,7 @@ moveAdrift:
RSTA
SETD.0 DownLow
STA.0
INIA 0xFC
INIA 0xF4
SETD.0 DownHigh
STA.0
@@ -1775,6 +1786,210 @@ touchdownStop:
touchdownDone:
RET
; ---- Docking, which is landing on something that is moving ----
;
; The same shape as touchdown and for the same reason: close enough, and slow enough, or it is
; a wreck. What makes it a different skill is that "slow enough" is measured against the
; STATION rather than against nothing. Its speed is orbital speed, which is the number the
; marks on the drift bar point at - so the instrument for this was already on the screen
; before there was anything to dock with.
;
; The tolerances are the ground's own, deliberately, so there is one number to argue with if
; this turns out to be too kind.
dock:
SETD.0 Docked
LDA.0
BNA dockRiding
; ---- Close enough, going round ----
;
; Wrapped to fourteen bits like everything else on this moon, which measures the long way
; round when the station is behind, so past the half way point is turned into a distance
; backwards before its size is taken.
SETD.0 StationLow
LDA.0
SETD.1 AcrossLow
LDB.1
CCF
SUB
SETD.1 DockGapLow
STQ.1
SETD.0 StationHigh
LDA.0
SETD.1 AcrossHigh
LDB.1
SUB
MVQA
INIB 0x3F
AND
SETD.1 DockGapHigh
STQ.1
LDA.1
INIB 0x20
AND
BRQ dockGapNear
SETD.0 DockGapHigh
LDA.0
INIB 0x40
CCF
SUB
STQ.0
dockGapNear:
SETD.0 DockGapLow
CALL magnitude
SETD.0 DriftHigh
LDA.0
BNA dockDone
SETD.0 DriftLow
LDA.0
INIB 0d128
CCF
SUB
BNC dockDone ; A whole tile away or more, so there is nothing to touch.
; ---- And close enough, up and down ----
SETD.0 StationDownLow
LDA.0
SETD.1 DownLow
LDB.1
CCF
SUB
SETD.1 DockRiseLow
STQ.1
SETD.0 StationDownHigh
LDA.0
SETD.1 DownHigh
LDB.1
SUB
SETD.1 DockRiseHigh
STQ.1
SETD.0 DockRiseLow
CALL magnitude
SETD.0 DriftHigh
LDA.0
BNA dockDone
SETD.0 DriftLow
LDA.0
INIB 0d128
CCF
SUB
BNC dockDone
; ---- Touching. Now, how fast, and RELATIVE TO WHAT ----
;
; The station is going at orbital speed, so a lander going at orbital speed is standing still
; beside it however fast the ground below says they are both travelling. That difference is
; the whole of the manoeuvre.
SETD.0 SpeedAcross
LDA.0
INIB 0d64
CCF
SUB
SETD.1 DockVxLow
STQ.1
INCD.0
LDA.0
RSTB
SUB ; And the borrow, which is the other half of the difference.
SETD.1 DockVxHigh
STQ.1
SETD.0 DockVxLow
CALL magnitude
SETD.0 DriftHigh
LDA.0
BNA dockStruck
SETD.0 DriftLow
LDA.0
SETD.1 GentleAcross
LDB.1
CCF
SUB
BNC dockStruck
; Downwards, where the station has no speed at all, so the difference is simply the fall.
SETD.0 SpeedDown
CALL magnitude
SETD.0 DriftHigh
LDA.0
BNA dockStruck
SETD.0 DriftLow
LDA.0
SETD.1 GentleDown
LDB.1
CCF
SUB
BNC dockStruck
; ---- Aboard ----
INIA 0x01
SETD.0 Docked
STA.0
CALL payFuel
SETD.0 DockedText
CALL sayInWindow
CALL waitKey
dockDone:
RET
dockStruck:
SETD.0 StruckText
BRI touchdownStop ; Which settles the view, says it, and ends the run.
; ---- Riding, until something is leaned on ----
;
; Held to the station rather than merely paid by it, because that is what docking IS. The
; speeds are the station's, so the pair drift round together, and the lander sits one tile
; under it so both are still visible.
;
; ANY thruster lets go. It has to be checked before the speeds are put back, or a burn would
; be wiped by the snap on the very frame it was made and the lander could never leave.
dockRiding:
SETD.0 Held
LDA.0
INIB 0x0F
AND
BNQ dockLetGo
SETD.0 StationLow
LDA.0
SETD.1 AcrossLow
STA.1
SETD.0 StationHigh
LDA.0
SETD.1 AcrossHigh
STA.1
SETD.0 StationDownLow
LDA.0
INIB 0d128
CCF
ADD
SETD.1 DownLow
STQ.1
SETD.0 StationDownHigh
LDA.0
RSTB
ADD ; One tile below it, carry included.
SETD.1 DownHigh
STQ.1
INIA 0d64
SETD.0 SpeedAcross
STA.0
RSTA
INCD.0
STA.0 ; Orbital speed exactly, which is what it is riding.
SETD.0 SpeedDown
STA.0
INCD.0
STA.0
RET
dockLetGo:
RSTA
SETD.0 Docked
STA.0
RET
; ---- A key, or a button ----
;
; Somebody flying on a controller should not have to reach for the keyboard to say "yes, I
@@ -1850,22 +2065,26 @@ showHeight:
AND
BNQ showHeightNone ; Negative: the feet are under the surface, so there is no sky.
LDA.0 ; The AND left A alone, so it still holds the high half.
INIB 0d16
INIB 0d32
CCF
SUB
BNC showHeightFull ; 4,096 sixteenths or more, which is the whole bar and then some.
BNC showHeightFull ; 8,192 sixteenths or more, which is the whole bar and then some.
LDA.0 ; DP0 still names the high half, and the compare did not touch A.
SETD.0 HeightLow
LDB.0
SHL
SHL
SHL ; ---- Over thirty two, which comes out in A ----
SHL ; ---- Over sixty four, which comes out in A ----
;
; A is the HIGH half of the shift register, so three turns LEFT of
; the whole sixteen bits leaves bits five to twelve in A - which is
; the height over thirty two, in one instruction each and no
; A is the HIGH half of the shift register, so two turns LEFT of
; the whole sixteen bits leaves bits six to thirteen in A - which
; is the height over sixty four, in one instruction each and no
; division anywhere.
;
; Over sixty four rather than thirty two because the ceiling moved:
; the band is 368 pixels now, and half a pixel of bar to a pixel of
; sky would stand 184 tall and run off the top of the forty column
; screen it is drawn beside.
BRI showHeightReady
showHeightFull:
INIA 0d127
@@ -2775,6 +2994,21 @@ Carrying:
0x00
Landed:
0x00
; Holding onto the station, which is the same kind of rest as sitting on the ground.
Docked:
0x00
DockGapLow:
0x00
DockGapHigh:
0x00
DockRiseLow:
0x00
DockRiseHigh:
0x00
DockVxLow:
0x00
DockVxHigh:
0x00
; Whether the lander is pinned against the ceiling, so the warning is said once rather than
; sixty times a second and taken away when it comes back down.
@@ -2796,6 +3030,10 @@ EmptyText:
0x00
CrashedText:
"Crashed."
DockedText:
"Docked. Eighty units of fuel."
StruckText:
"Wrecked against the station."
; ---- The station, which is a body and not a special case ----
;
@@ -2817,7 +3055,14 @@ StationHigh:
StationDownLow:
0x00
StationDownHigh:
0xFE ; Minus 512 sixteenths, which is four rows up.
0xFA ; ---- Minus 1,536 sixteenths, which is twelve rows up ----
;
; About two thirds of the way from the ground to the ceiling. It
; was four rows up when four rows was most of the sky there was,
; which put it exactly where anything climbing away from the
; surface had to pass - and being run down there is not a hazard,
; it is a toll. Twelve rows up is clear of work near the ground and
; still a dozen rows under the ceiling.
StationSpeed:
0x40 0x00 ; Orbital speed, and the whole of its behaviour.