Dust on landing, gas on letting go, and a lander that stays let go
One particle system, three uses now: a lander coming apart, dust kicked up by a landing, and gas out of a docking port on release. Where they start, how fast they go, what colour they are and how long they last are arguments; everything else is shared. Dust goes sideways and UP off the lander's feet, because that is where kicked dust goes and there is ground in the way of the rest of it. Gas goes evenly in every direction, because nothing is in the way of a docking port. Neither happens on docking - a dock is a catch and not a touchdown, and there is nothing under it to kick. ---- Ticked from the frame loop, not run in place ---- The explosion can afford to stop the world; there is nothing left to fly. The undocking puff cannot, because it goes off on the frame a thruster is pressed, and freezing a quarter of a second exactly then is felt as the controls sticking. So a burst advances one frame at a time from the main loop, and the two that can afford to wait just pump that same tick until the air is clear. ---- And letting go did not let go ---- Which the puff is what found. A docked lander sits EXACTLY one tile under the station, so releasing upwards moved it towards the station and it docked again on the very next frame: took the fuel again, said so again, and waited to be told the message had been read - which reads as the controls locking up the instant they are used. It has to get clear now before it can take hold again, and the two distances have to differ: docking wants one tile, re-arming wants two. A single distance re-armed on the frame it let go, because a tile is exactly where it was sitting. Three checks, each seen to fail on its own break. The last of them measures HOW FAR the lander has got and not merely that it moved: a sixteen frame pause on release still leaves it climbing, four rows short of a free run, so "it moved" would pass for a stall that has been slept through.
This commit is contained in:
Anachronaut
+222
-42
@@ -112,6 +112,7 @@ everyFrame:
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CALL showFall
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CALL showFuel
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CALL showHeight
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CALL burstTick ; Whatever is in the air, one frame on.
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SETD.0 Flying
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LDA.0
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BNA everyFrame
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@@ -1795,6 +1796,8 @@ touchdown:
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SUB
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BNC touchdownCrash
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CALL landingDust ; Something to see for an arrival, as a crash has always had.
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; ---- Down safely, which is not the end of anything ----
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;
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; The view settles, the arrival is dealt with, and the lander sits where it is until
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@@ -1877,13 +1880,13 @@ dock:
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CALL magnitude
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SETD.0 DriftHigh
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LDA.0
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BNA dockDone
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BNA dockAway ; 256 sixteenths or more, which is properly out of the way.
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SETD.0 DriftLow
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LDA.0
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INIB 0d128
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CCF
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SUB
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BNC dockDone ; A whole tile away or more, so there is nothing to touch.
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BNC dockDone ; A tile away or more: too far to dock, not far enough to re-arm.
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; ---- And close enough, up and down ----
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SETD.0 StationDownLow
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@@ -1905,7 +1908,7 @@ dock:
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CALL magnitude
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SETD.0 DriftHigh
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LDA.0
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BNA dockDone
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BNA dockAway
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SETD.0 DriftLow
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LDA.0
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INIB 0d128
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@@ -1913,6 +1916,19 @@ dock:
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SUB
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BNC dockDone
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; ---- Still in the doorway it just left by ----
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;
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; Letting go UPWARDS moves the lander towards the station, so without this it docked again on
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; the very next frame - took the fuel again, said so again, and waited to be told the message
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; had been read, which reads as the controls locking up the instant they are used.
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;
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; TWO DISTANCES, and they have to be different. Docking wants a tile; re-arming wants two,
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; because a lander riding the station sits EXACTLY a tile under it - so a single distance
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; re-armed on the very frame it let go, and the frame after that it was back on.
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SETD.0 DockClear
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LDA.0
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BRA dockDone
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; ---- Touching. Now, how fast, and RELATIVE TO WHAT ----
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;
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; The station is going at orbital speed, so a lander going at orbital speed is standing still
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@@ -1966,6 +1982,12 @@ dock:
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SETD.0 DockedText
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CALL sayInWindow
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CALL waitKey
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RET
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dockAway:
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INIA 0x01
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SETD.0 DockClear
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STA.0 ; Two tiles off, so the next arrival counts as an arrival.
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dockDone:
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RET
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@@ -2034,6 +2056,9 @@ dockLetGo:
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RSTA
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SETD.0 Docked
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STA.0
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SETD.0 DockClear
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STA.0 ; A is still nought: not clear until it has actually got away.
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CALL undockGas ; Started and left running: the pilot is mid-burn.
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RET
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; ---- Half a pixel of the way there, or the whole of it if that is nearer ----
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@@ -2322,41 +2347,53 @@ putFlame:
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OUTA 0xE9 ; And no depth.
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RET
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; ---- Coming apart, which is the only thing on this screen that is not a number ----
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; ---- Six pieces of something, thrown out from somewhere ----
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;
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; A crash used to be a line of text and a lander still sitting there in one piece. The verdict
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; was the whole of it, and somebody watching a recording had to read the words to know what had
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; happened - the same problem the flames were for.
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; One system, three uses: a lander coming apart, dust kicked up by a landing, and gas out of a
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; docking port on release. What differs is where they start, how fast they go, what colour
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; they are and how long they last, so all four of those are arguments and the rest is shared.
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;
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; The lander goes and six pieces of it leave in a rough hexagon, at its own colour, for half a
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; second. The world is not running while this happens: it is a loop of its own, so nothing has
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; to know how to be half destroyed.
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explode:
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RSTA
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CALL hideSprite ; The lander itself.
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INIA 0x70
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CALL hideSprite
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INIA 0x80
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CALL hideSprite ; And both flames, which would otherwise hang in the air.
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; ---- Ticked from the frame loop rather than run in place ----
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;
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; The explosion can afford to stop the world - there is nothing left to fly. The undocking puff
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; CANNOT: it goes off on the frame a thruster is pressed, and freezing for a quarter of a
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; second exactly then would be felt as the controls sticking. So the burst advances one frame
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; at a time from the main loop, and the two that can afford to wait simply pump that same tick
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; until it runs out.
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startBurst:
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; DP0 names six pairs of speeds; the origin, colour and length are already set.
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SETD.1 BurstV
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INIA 0d24
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SETD.2 CopyLeft
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STA.2
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startBurstCopy:
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LDA.0
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STA.1
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INCD.0
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INCD.1
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SETD.2 CopyLeft
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LDA.2
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DECA
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STA.2
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BNA startBurstCopy
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; Every piece starts where the lander was.
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RSTA
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SETD.0 SparkAt
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STA.0
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INIA 0d6
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SETD.0 SparkCount
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STA.0
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explodeStart:
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; DP0 is what copyWord reads and DP1 what it writes, so the lander's place is DP0. Written
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; the other way round first, which copied the empty sparks OVER ShipX - and since that is
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; the view block, the lander's own column with it.
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SETD.0 ShipX
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startBurstPlace:
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; DP0 is what copyWord reads and DP1 what it writes, so the origin is DP0. Written the other
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; way round first, which copied the empty pieces OVER ShipX - and since that is in the view
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; block, the lander's own column went with them.
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SETD.0 BurstOXLow
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SETD.1 Spark
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SETD.2 SparkAt
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LDA.2
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DPUA.1
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CALL copyWord
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SETD.0 ShipTopLow
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SETD.0 BurstOYLow
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SETD.1 Spark
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SETD.2 SparkAt
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LDA.2
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@@ -2374,13 +2411,14 @@ explodeStart:
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LDA.0
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DECA
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STA.0
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BNA explodeStart
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BNA startBurstPlace
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RET
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INIA 0d48
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SETD.0 SparkLeft
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STA.0 ; Getting on for a second, which is long enough to watch.
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explodeFrame:
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CALL waitFrame
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; One frame of whatever is in the air. Nothing at all when nothing is.
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burstTick:
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SETD.0 BurstLeft
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LDA.0
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BRA burstTickDone
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RSTA
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SETD.0 SparkAt
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STA.0
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@@ -2390,12 +2428,12 @@ explodeFrame:
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INIA 0d6
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SETD.0 SparkCount
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STA.0
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explodeOne:
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burstOne:
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SETD.0 Spark
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SETD.2 SparkAt
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LDA.2
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DPUA.0
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SETD.1 SparkV
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SETD.1 BurstV
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DPUA.1
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CALL addWord ; Across, by however fast this piece is going.
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SETD.0 Spark
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@@ -2404,7 +2442,7 @@ explodeOne:
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INCA
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INCA
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DPUA.0
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SETD.1 SparkV
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SETD.1 BurstV
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DPUA.1
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CALL addWord ; And down.
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CALL putSpark
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@@ -2425,22 +2463,26 @@ explodeOne:
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LDA.0
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DECA
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STA.0
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BNA explodeOne
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BNA burstOne
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SETD.0 SparkLeft
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SETD.0 BurstLeft
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LDA.0
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DECA
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STA.0
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BNA explodeFrame
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BNA burstTickDone
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CALL hideBurst ; The last frame of it, so they go rather than hang there.
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burstTickDone:
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RET
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; And away, or they would sit there under the verdict.
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; Every piece off the screen, which is a size of nought six times.
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hideBurst:
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INIA 0x90
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SETD.0 SparkSlot
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STA.0
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INIA 0d6
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SETD.0 SparkCount
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STA.0
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explodeClear:
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hideBurstOne:
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SETD.0 SparkSlot
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LDA.0
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CALL hideSprite
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@@ -2454,7 +2496,103 @@ explodeClear:
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LDA.0
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DECA
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STA.0
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BNA explodeClear
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BNA hideBurstOne
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RET
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; For the two that can afford to wait: pump the tick until there is nothing left in the air.
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runBurst:
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CALL waitFrame
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CALL burstTick
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SETD.0 BurstLeft
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LDA.0
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BNA runBurst
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RET
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; ---- Coming apart, which is the only thing on this screen that is not a number ----
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;
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; A crash used to be a line of text and a lander still sitting there in one piece. The verdict
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; was the whole of it, and somebody watching a recording had to read the words to know what had
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; happened - the same problem the flames were for.
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explode:
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RSTA
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CALL hideSprite ; The lander itself.
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INIA 0x70
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CALL hideSprite
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INIA 0x80
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CALL hideSprite ; And both flames, which would otherwise hang in the air.
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SETD.0 ShipX
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SETD.1 BurstOXLow
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CALL copyWord
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SETD.0 ShipTopLow
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SETD.1 BurstOYLow
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CALL copyWord
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INIA 0x03
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SETD.0 BurstColour
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STA.0 ; Yellow: it is the lander that is coming apart.
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INIA 0d48
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SETD.0 BurstLeft
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STA.0 ; Getting on for a second, which is long enough to watch.
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SETD.0 SparkV
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CALL startBurst
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CALL runBurst
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RET
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; ---- Dust, for a landing that went right ----
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;
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; A crash has had something to watch since the pieces arrived, and an arrival did not. The
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; puff comes off the LANDER'S FEET rather than its middle, which is where the ground is, and
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; it goes sideways and up because that is where kicked dust goes.
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;
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; Not on docking. A dock is a catch and not a touchdown - there is nothing under it to kick.
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landingDust:
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SETD.0 ShipX
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SETD.1 BurstOXLow
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CALL copyWord
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SETD.0 ShipTopLow
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LDA.0
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INIB 0d8
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CCF
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ADD
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SETD.1 BurstOYLow
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STQ.1
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SETD.0 ShipTopHigh
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LDA.0
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RSTB
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ADD ; A tile down from its top, which is where its feet are.
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SETD.1 BurstOYHigh
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STQ.1
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INIA 0x07
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SETD.0 BurstColour
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STA.0 ; White, which is the one thing on this moon that is not grey.
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INIA 0d16
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SETD.0 BurstLeft
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STA.0
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SETD.0 DustV
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CALL startBurst
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CALL runBurst
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RET
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; ---- And gas, for letting go of a station ----
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;
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; Something has to come out of a docking port when it lets go, and this is a small symmetric
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; puff of it. STARTED AND LEFT RUNNING, unlike the other two: it happens on the frame a
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; thruster is pressed, and stopping the world exactly then would be felt as the controls
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; sticking rather than as an effect.
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undockGas:
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SETD.0 ShipX
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SETD.1 BurstOXLow
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CALL copyWord
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SETD.0 ShipTopLow
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SETD.1 BurstOYLow
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CALL copyWord
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INIA 0x07
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SETD.0 BurstColour
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STA.0
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INIA 0d16
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SETD.0 BurstLeft
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STA.0
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SETD.0 GasV
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CALL startBurst
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RET
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; One piece, where the pointers say it now is.
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@@ -2468,8 +2606,9 @@ putSpark:
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OUTA 0xE5
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INIA 0xC8
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OUTA 0xE9 ; The solid block, at two pixels by two.
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INIA 0x03
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OUTA 0xE9 ; Yellow: it is the lander that is coming apart.
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SETD.0 BurstColour
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LDA.0
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OUTA 0xE9
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SETD.0 Spark
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SETD.2 SparkAt
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LDA.2
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@@ -3639,6 +3778,11 @@ ShipTopHigh:
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; beside them are a rough hexagon, so it comes apart evenly rather than in a line.
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Spark:
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#Reserve 0d24
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; The speeds in use this burst, copied over from one of the three below.
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BurstV:
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#Reserve 0d24
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; A lander coming apart: a rough hexagon at two pixels a frame, so it goes evenly.
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SparkV:
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0x02 0x00 0x00 0x00
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0x01 0x00 0x02 0x00
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@@ -3646,13 +3790,45 @@ SparkV:
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0xFE 0xFF 0x00 0x00
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0xFF 0xFF 0xFE 0xFF
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0x01 0x00 0xFE 0xFF
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; Dust off a landing: sideways and UP, because that is where kicked dust goes, and none of it
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; downwards because there is ground in the way.
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DustV:
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0x03 0x00 0x00 0x00
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0xFD 0xFF 0x00 0x00
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0x02 0x00 0xFF 0xFF
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0xFE 0xFF 0xFF 0xFF
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0x01 0x00 0xFE 0xFF
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0xFF 0xFF 0xFE 0xFF
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; Gas out of a docking port: small, even, and in every direction, because nothing is in the way.
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GasV:
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0x02 0x00 0x00 0x00
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0xFE 0xFF 0x00 0x00
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0x01 0x00 0x01 0x00
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0xFF 0xFF 0x01 0x00
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0x01 0x00 0xFF 0xFF
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0xFF 0xFF 0xFF 0xFF
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SparkAt:
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0x00
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SparkSlot:
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0x00
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SparkCount:
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0x00
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SparkLeft:
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BurstLeft:
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0x00
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BurstColour:
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0x00
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BurstOXLow:
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0x00
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BurstOXHigh:
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0x00
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BurstOYLow:
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0x00
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BurstOYHigh:
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0x00
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CopyLeft:
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0x00
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HideSlot:
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0x00
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@@ -3686,6 +3862,10 @@ FlameBack:
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; Holding onto the station, which is the same kind of rest as sitting on the ground.
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Docked:
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0x00
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; Whether it has been clear of the station since it last let go. It starts clear, having never
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; been attached to anything.
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DockClear:
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0x01
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; Where the lander is sliding to, and how far it has to go to get there.
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DockTargetLow:
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0x00
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Reference in New Issue
Block a user