' scen/fall.txt - finding 1.3: what a freefall does to a character.
'
' Level 7 opens with the kid standing on nothing: screen 17 is three rows of
' empty and he is put at (2,2), so he is in freefall from the first frame.
' That makes it the place to watch a fall, and it is the level the finding is
' about.

' (a) SUBS.S ADDFALL adds the horizontal velocity to X on every freefall
' frame.  The port set cXVel from the sequence and then never moved him with
' it, so every fall was dead vertical.  He faces left, so the drift is left.
SCEN a fall carries his horizontal velocity too
AT 7 17 2 2
SEED 17
RUN ..........
WANT XVEL 1
WANT X LE 95
WANT FALLING 1
END

' (b) SUBS.S GRAVITY caps an ordinary fall at thirty-three.  The port added
' three a frame for ever, and since the landing severity is read straight off
' this speed, a long fall killed where the original only hurt.
SCEN a fall gathers speed to thirty-three and no further
AT 7 17 2 2
SEED 17
RUN ..............
WANT YVEL 33
WANT ALIVE 1
END

' (b) again, the other half: while the float potion is in him gravity is one
' a frame to a terminal four.  The potion on level 7 screen 1 exists to make
' the long drop survivable, and in the port it changed nothing.  Here it is
' the difference between landing on the ledge at column 1 of screen 1 and
' going on down the shaft to die at the foot of screen 3.
SCEN the float potion makes the drop survivable
START 7
FLOAT 60
SEED 17
RUN ..................
WANT YVEL LE 4
WANT ALIVE 1
WANT DEATHS 0
WANT HARD 0
WANT SCRN 1
END

' (e) SUBS.S GRAVITY begins "lda CharAction / cmp #4 / bne rts", so it does
' nothing until the fall is a freefall.  The first four frames of a fall are
' action 3 and belong to the sequence: its own chy opcodes move him down 3, 6,
' 9 and 12, and the setfall at the end of them is what seeds the velocity the
' freefall then accelerates.  The port ran gravity from the step-off frame as
' well, so those four frames were moved twice and every fall was thirty pixels
' lower by the fourth of them, and reached the floor a frame early.
'
' Walking off the ledge at column three of screen 1, twenty frames in, he is
' on the fourth of those frames: down 30 from 55, and still carrying no
' velocity of his own.
SCEN the first frames of a fall are the sequence's, not gravity's
AT 1 1 5 0
SEED 17
RUN ..>>>>>>>>>>>>>>>>>>>>
WANT Y 85
WANT YVEL 0
WANT FALLING 1
WANT ACTION 3
END
