mirror of
https://github.com/irmen/prog8.git
synced 2024-11-28 10:51:14 +00:00
211 lines
7.8 KiB
Lua
211 lines
7.8 KiB
Lua
%import syslib
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%import textio
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%import math
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; C64 version of a balloon sprites flying over a mountain landscape.
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; There is also a X16 version of this in the examples.
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main {
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bool do_char_scroll = false
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sub start() {
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uword moon_x = 310
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c64.set_sprite_ptr(0, $0f00) ; alternatively, set directly: c64.SPRPTR[0] = $0f00 / 64
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c64.set_sprite_ptr(1, $0f00+64) ; alternatively, set directly: c64.SPRPTR[0] = $0f00 / 64
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c64.SPENA = %00000011
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c64.SP0COL = 14
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c64.SP1COL = 7
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c64.SPXY[0] = 80
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c64.SPXY[1] = 100
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set_moon_pos(moon_x)
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c64.SCROLX &= %11110111 ; 38 column mode
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sys.set_rasterirq(&irq.irqhandler, 250) ; enable animation via raster interrupt
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ubyte target_height = 10
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ubyte active_height = 25
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bool upwards = true
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repeat {
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ubyte mountain = 223 ; slope upwards
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if active_height < target_height {
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active_height++
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upwards = true
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} else if active_height > target_height {
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mountain = 233 ; slope downwards
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active_height--
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upwards = false
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} else {
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; determine new height for next mountain
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ubyte old_height = target_height
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if upwards {
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mountain = 233
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while target_height >= old_height
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target_height = 9 + math.rnd() % 15
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} else {
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mountain = 223
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while target_height <= old_height
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target_height = 9 + math.rnd() % 15
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}
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}
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while not do_char_scroll {
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; let the raster irq do its timing job
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}
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do_char_scroll = false
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scroll_characters_left()
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; float the balloon and the moon sprites
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if math.rnd() & 1 !=0
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c64.SPXY[1] ++
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else
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c64.SPXY[1] --
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moon_x--
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if msb(moon_x)==255
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moon_x = 340
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set_moon_pos(moon_x)
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; draw new mountain etc.
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const ubyte RIGHT_COLUMN = 39
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ubyte yy
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for yy in 0 to active_height-1 {
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txt.setcc(RIGHT_COLUMN, yy, 32, 2) ; clear top of screen
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}
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txt.setcc(RIGHT_COLUMN, active_height, mountain, 8) ; mountain edge
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for yy in active_height+1 to 24 {
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txt.setcc(RIGHT_COLUMN, yy, 160, 8) ; draw filled mountain
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}
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ubyte clutter = math.rnd()
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if clutter > 100 {
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; draw a star
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txt.setcc(RIGHT_COLUMN, clutter % (active_height-1), sc:'.', math.rnd())
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}
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if clutter > 200 {
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; draw a tree
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ubyte tree = sc:'↑'
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ubyte treecolor = 5
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if clutter & %00010000 != 0
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tree = sc:'♣'
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else if clutter & %00100000 != 0
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tree = sc:'♠'
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if math.rnd() > 130
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treecolor = 13
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txt.setcc(RIGHT_COLUMN, active_height, tree, treecolor)
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}
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if clutter > 235 {
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; draw a camel
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txt.setcc(RIGHT_COLUMN, active_height, sc:'π', 9)
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}
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}
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}
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sub set_moon_pos(uword x) {
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c64.SPXY[2] = lsb(x)
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c64.SPXY[3] = 55
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if msb(x)!=0
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c64.MSIGX |= %00000010
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else
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c64.MSIGX &= %11111101
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}
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sub scroll_characters_left () {
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; Scroll the bottom half (approx.) of the character screen 1 character to the left
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; contents of the rightmost column are unchanged, you should clear/refill this yourself
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; Without clever split-screen tricks, the C64 is not fast enough to scroll the whole
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; screen smootly without tearing. So for simplicity it's constrained to less rows
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; such that what is scrolled, *does* scrolls smoothly.
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; For maximum performance the scrolling is done in unrolled assembly code.
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%asm {{
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ldx #0
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ldy #38
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-
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.for row=10, row<=24, row+=1
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lda cbm.Screen + 40*row + 1,x
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sta cbm.Screen + 40*row + 0,x
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lda cbm.Colors + 40*row + 1,x
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sta cbm.Colors + 40*row + 0,x
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.next
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inx
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dey
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bpl -
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rts
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}}
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}
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}
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irq {
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; does the smooth scrolling immediately after the visible screen area,
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; so there is no screen tearing. The main loop does the "big" character
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; scrolling when the soft-scroll runs out after 8 pixels
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ubyte smoothx=0
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sub irqhandler() -> bool {
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smoothx = (smoothx-1) & 7
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main.do_char_scroll = smoothx==7
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c64.SCROLX = (c64.SCROLX & %11111000) | smoothx
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return false
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}
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}
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spritedata $0f00 {
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; this memory block contains the sprite data. it must start on an address aligned to 64 bytes.
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; for simplicity, it's currently statically located at $0f00 (not far in memory after the program code),
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; but there are ways to do this more dynamically.
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%option force_output ; make sure the data in this block appears in the resulting program
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ubyte[] balloonsprite = [ %00000000,%01111111,%00000000,
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%00000001,%11111111,%11000000,
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%00000011,%11111111,%11100000,
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%00000011,%11100011,%11100000,
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%00000111,%11011100,%11110000,
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%00000111,%11011101,%11110000,
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%00000111,%11011100,%11110000,
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%00000011,%11100011,%11100000,
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%00000011,%11111111,%11100000,
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%00000011,%11111111,%11100000,
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%00000010,%11111111,%10100000,
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%00000001,%01111111,%01000000,
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%00000001,%00111110,%01000000,
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%00000000,%10011100,%10000000,
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%00000000,%10011100,%10000000,
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%00000000,%01001001,%00000000,
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%00000000,%01001001,%00000000,
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%00000000,%00111110,%00000000,
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%00000000,%00111110,%00000000,
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%00000000,%00111110,%00000000,
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%00000000,%00011100,%00000000,
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0]
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ubyte[] moonsprite = [ %00000000,%00000110,%00000000,
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%00000000,%00011100,%00000000,
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%00000000,%01111000,%00000000,
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%00000000,%11111000,%00000000,
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%00000001,%11110000,%00000000,
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%00000011,%11110000,%00000000,
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%00000011,%11110000,%00000000,
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%00000111,%11100000,%00000000,
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%00000111,%11100000,%00000000,
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%00000111,%11100000,%00000000,
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%00000111,%11100000,%00000000,
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%00000111,%11100000,%00000000,
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%00000111,%11100000,%00000000,
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%00000111,%11100000,%00000000,
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%00000011,%11110000,%00000000,
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%00000011,%11110000,%00000000,
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%00000001,%11110000,%00000000,
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%00000000,%11111000,%00000000,
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%00000000,%01111000,%00000000,
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%00000000,%00011100,%00000000,
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%00000000,%00000110,%00000000,
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0]
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}
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