prog8/examples/balloonflight.p8

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2020-03-28 16:06:17 +00:00
%import c64lib
%import c64utils
%zeropage basicsafe
main {
ubyte perform_scroll = false
sub start() {
c64.SPRPTR[0] = $0f00 / 64
c64.SPENA = 1
c64.SP0COL = 14
c64.SPXY[0] = 80
c64.SPXY[1] = 100
c64.SCROLX &= %11110111 ; 38 column mode
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c64utils.set_rasterirq(1) ; enable animation
ubyte target_height = 10
ubyte active_height = 24
ubyte upwards = true
repeat {
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ubyte mountain = 223 ; slope upwards
if active_height < target_height {
active_height++
upwards = true
} else if active_height > target_height {
mountain = 233 ; slope downwards
active_height--
upwards = false
} else {
target_height = 8 + rnd() % 16
if upwards
mountain = 233
else
mountain = 223
}
while not perform_scroll {
; let the raster irq do its timing job
}
perform_scroll = false
c64scr.scroll_left_full(true)
if c64.RASTER & 1
c64.SPXY[1] ++
else
c64.SPXY[1] --
ubyte yy
for yy in 0 to active_height-1 {
c64scr.setcc(39, yy, 32, 2) ; clear top of screen
}
c64scr.setcc(39, active_height, mountain, 8) ; mountain edge
for yy in active_height+1 to 24 {
c64scr.setcc(39, yy, 160, 8) ; draw mountain
}
yy = rnd()
if yy > 100 {
; draw a star
c64scr.setcc(39, yy % (active_height-1), '.', rnd())
}
if yy > 200 {
; draw a tree
ubyte tree = 30
ubyte treecolor = 5
if yy & %01000000 != 0
tree = 88
else if yy & %00100000 != 0
tree = 65
if rnd() > 130
treecolor = 13
c64scr.setcc(39, active_height, tree, treecolor)
}
if yy > 235 {
; draw a camel
c64scr.setcc(39, active_height, 94, 9)
}
}
}
}
spritedata $0f00 {
; this memory block contains the sprite data
; it must start on an address aligned to 64 bytes.
%option force_output ; make sure the data in this block appears in the resulting program
ubyte[] balloonsprite = [ %00000000,%01111111,%00000000,
%00000001,%11111111,%11000000,
%00000011,%11111111,%11100000,
%00000011,%11100011,%11100000,
%00000111,%11011100,%11110000,
%00000111,%11011101,%11110000,
%00000111,%11011100,%11110000,
%00000011,%11100011,%11100000,
%00000011,%11111111,%11100000,
%00000011,%11111111,%11100000,
%00000010,%11111111,%10100000,
%00000001,%01111111,%01000000,
%00000001,%00111110,%01000000,
%00000000,%10011100,%10000000,
%00000000,%10011100,%10000000,
%00000000,%01001001,%00000000,
%00000000,%01001001,%00000000,
%00000000,%00111110,%00000000,
%00000000,%00111110,%00000000,
%00000000,%00111110,%00000000,
%00000000,%00011100,%00000000 ]
}
irq {
ubyte smoothx=7
sub irq() {
smoothx = (smoothx-1) & 7
main.perform_scroll = smoothx==0
c64.SCROLX = (c64.SCROLX & %11111000) | smoothx
}
}