mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-11-01 01:06:33 +00:00
190 lines
2.0 KiB
ArmAsm
190 lines
2.0 KiB
ArmAsm
; particle effect? -- Apple II Lores
|
|
|
|
; by Vince `deater` Weaver
|
|
|
|
PARTICLES = 128
|
|
SCALE = 2
|
|
|
|
COLOR = $30
|
|
|
|
QUOTIENT = $FA
|
|
DIVISOR = $FB
|
|
DIVIDEND = $FC
|
|
XX = $FD
|
|
YY = $FE
|
|
FRAME = $FF
|
|
|
|
FULLGR = $C052
|
|
LORES = $C056 ; Enable LORES graphics
|
|
|
|
HGR2 = $F3D8
|
|
HGR = $F3E2
|
|
PLOT = $F800 ; PLOT AT Y,A (A colors output, Y preserved)
|
|
SETGR = $FB40
|
|
WAIT = $FCA8 ; delay 1/2(26+27A+5A^2) us
|
|
|
|
|
|
particle_x = $2000
|
|
particle_y = $2100
|
|
particle_life = $2200
|
|
particle_vx = $2300
|
|
particle_vy = $2400
|
|
particle_decay = $2600
|
|
|
|
particle:
|
|
|
|
jsr SETGR
|
|
bit FULLGR
|
|
|
|
; init
|
|
|
|
ldx #PARTICLES
|
|
init_particles_loop:
|
|
jsr init_particle
|
|
dex
|
|
bpl init_particles_loop
|
|
|
|
|
|
|
|
main_loop:
|
|
|
|
lda #200
|
|
jsr WAIT
|
|
|
|
; clear screen
|
|
ldx #0
|
|
lda #$8
|
|
sta clear_loop_smc+2
|
|
lda #0
|
|
|
|
clear_loop:
|
|
|
|
clear_loop_smc:
|
|
sta $400,X
|
|
dex
|
|
bne clear_loop
|
|
dec clear_loop_smc+2
|
|
ldy clear_loop_smc+2
|
|
cpy #3
|
|
bne clear_loop
|
|
|
|
; move particles
|
|
; draw particles
|
|
ldx #PARTICLES
|
|
draw_particles_loop:
|
|
|
|
; adjust x
|
|
|
|
lda particle_x,X
|
|
clc
|
|
adc particle_vx,X
|
|
sta particle_x,X
|
|
bmi redo_particle
|
|
cmp #40*SCALE
|
|
bcs redo_particle
|
|
|
|
; adjust y
|
|
|
|
; first adjust for gravity
|
|
inc particle_vy,X
|
|
; inc particle_vy,X
|
|
|
|
lda particle_y,X
|
|
clc
|
|
adc particle_vy,X
|
|
sta particle_y,X
|
|
bmi redo_particle
|
|
cmp #48*SCALE
|
|
bcc y_good
|
|
|
|
redo_particle:
|
|
jsr init_particle
|
|
|
|
y_good:
|
|
|
|
lda particle_life,X
|
|
sta COLOR
|
|
sec
|
|
sbc #$11
|
|
sta particle_life,X
|
|
cmp #$ef
|
|
beq redo_particle
|
|
|
|
lda particle_x,X
|
|
lsr
|
|
tay
|
|
|
|
lda particle_y,X
|
|
lsr
|
|
jsr PLOT ; PLOT AT Y,A
|
|
|
|
dex
|
|
bpl draw_particles_loop
|
|
|
|
jmp main_loop
|
|
|
|
|
|
|
|
|
|
; init particle
|
|
; particle in X
|
|
init_particle:
|
|
|
|
; source
|
|
|
|
lda #20*SCALE
|
|
sta particle_x,X
|
|
lda #10*SCALE
|
|
sta particle_y,X
|
|
|
|
; color
|
|
lda #$ff
|
|
sta particle_life,X
|
|
|
|
; velocities
|
|
; -8 to 8?
|
|
|
|
jsr random
|
|
cmp #$80
|
|
ror
|
|
|
|
sta particle_vx,X
|
|
|
|
jsr random
|
|
sta particle_vy,X
|
|
|
|
; we don't actually use this?
|
|
|
|
; lda #32
|
|
; sta particle_decay,X
|
|
rts
|
|
|
|
|
|
; -8 to 8
|
|
random:
|
|
|
|
inc random_smc+1
|
|
bne noflo
|
|
inc random_smc+2
|
|
beq noflo
|
|
lda #$d0
|
|
sta random_smc+2
|
|
|
|
noflo:
|
|
|
|
random_smc:
|
|
lda $d000
|
|
|
|
and #$f
|
|
sec
|
|
sbc #$8
|
|
|
|
rts
|
|
|
|
|
|
|
|
|
|
; need this to be at $3F5
|
|
|
|
jmp particle
|