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Fire effect example

This commit is contained in:
Karol Stasiak 2018-12-29 20:12:19 +01:00
parent d7b2181ef5
commit 9a7086fd8c
2 changed files with 173 additions and 0 deletions

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* [Calculator](crossplatform/calculator.mfk) (C64/C16/ZX Spectrum/PC-88) simple numeric input and output
* [Fire effect](crossplatform/fire.mfk) (C64/C16/ZX Spectrum) a simple fire effect
* [Bell](crossplatform/bell.mfk) (Apple II/ZX Spectrum) a program that goes \*ding!\*
## Commodore 64 examples

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array reverse_palette[256] align(256)
#if CBM
const byte COLUMN_COUNT = 40
const byte ROW_COUNT = 25
array palette align(fast) = [black, red, orange, yellow, white]
void cls() {
byte i
for i,0,paralleluntil,250 {
screen[000+i] = 160
screen[250+i] = 160
screen[500+i] = 160
screen[750+i] = 160
}
for i,0,paralleluntil,250 {
colors[000+i] = black
colors[250+i] = black
colors[500+i] = black
colors[750+i] = black
}
}
#endif
#if CBM_64
array colors[1000] @$d800
array screen[1000] @$400
#elseif CBM_264
array colors[1000] @$800
array screen[1000] @$c00
#endif
#if ZX_SPECTRUM
#pragma zilog_syntax
array palette align(fast) = [black*9, red*9, red*9+$40, yellow*9+$40, white*9+$40]
array colors[$300] @$5800
const byte COLUMN_COUNT = 32
const byte ROW_COUNT = 24
void cls() {
pointer p
for p,$4000,paralleluntil,$5800 {
p[0] = $f7
}
for p,$5800,paralleluntil,$5b00 {
p[0] = black*9
}
}
#endif
void build_reverse_palette () {
byte i
#if CBM_64
byte j
for i,0,paralleluntil,palette.length {
for j,0,parallelto,$f {
reverse_palette[palette[i] | (j<<4)] = i
}
}
#else
for i,0,paralleluntil,palette.length {
reverse_palette[palette[i]] = i
}
#endif
}
void main() {
set_border(black)
init_rand_seed()
build_reverse_palette()
cls()
byte i
const word LAST_ROW_START = COLUMN_COUNT * word(ROW_COUNT-1)
for i,0,paralleluntil,COLUMN_COUNT {
colors[LAST_ROW_START+i] = palette[palette.length - 1]
}
while true {
wait_frame()
fire()
}
}
void wait_frame() {
#if CBM_64
while vic_raster != $ff {}
#elseif CBM_264
while ted_raster_y != $ff {}
#elseif ZX_SPECTRUM
asm { halt }
#else
// TODO
#endif
}
void fire() {
byte noise
byte row
byte column
pointer p
byte heat
byte entropy
entropy = 0
p = colors.addr
for row,0,paralleluntil,ROW_COUNT-1 {
for column,0,paralleluntil,COLUMN_COUNT {
if entropy == 0 {
noise = rand()
entropy = 8
}
heat = reverse_palette[p[column+COLUMN_COUNT]]
if noise & 1 != 0 {
if heat != 0 { heat -= 1 }
}
noise >>= 1
entropy -= 1
p[column] = palette[heat]
}
p += COLUMN_COUNT
}
}
word rand_seed
#if CPU_6502
asm byte rand() {
ldx #8
lda rand_seed+0
__rand_loop:
asl
rol rand_seed+1
bcc __no_eor
eor #$2D
__no_eor:
dex
bne __rand_loop
sta rand_seed+0
? rts
}
#elseif CPU_Z80
inline asm byte rand() {
ld b,8
ld hl,(rand_seed)
__rand_loop:
add hl,hl
jp nc, __no_eor
ld a,l
xor $2D
ld l,a
__no_eor:
djnz __rand_loop
ld (rand_seed),hl
? ret
}
#endif
#if CBM_64
inline void init_rand_seed() {
poke($D40E, $ff)
poke($D40F, $ff)
poke($D412, $80)
while vic_raster != $70 {}
rand_seed.hi = peek($D41B)
while vic_raster != $40 {}
rand_seed.lo = peek($D41B)
}
#else
inline void init_rand_seed() {
rand_seed = 1
}
#endif