dos33fsprogs/games/lemm/particle_hgr.s
2022-04-17 19:28:29 -04:00

214 lines
2.3 KiB
ArmAsm

; particle effect? -- Apple II Lores
; by Vince `deater` Weaver
PARTICLES = 32
SCALE = 2
;HGR_BITS = $1C
;COLOR = $30
;SEEDLO = $43
;SEEDHI = $44
;HGR_COLOR = $E4
;QUOTIENT = $FA
;DIVISOR = $FB
;DIVIDEND = $FC
;XX = $FD
;YY = $FE
;FRAME = $FF
;FULLGR = $C052
;LORES = $C056 ; Enable LORES graphics
;HGR2 = $F3D8
;HGR = $F3E2
;HPLOT0 = $F457 ; plot at (Y,X), (A)
;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 = $800
particle_y = $880
particle_life = $900
particle_vx = $980
particle_vy = $a00
init_particles:
; init
ldx #PARTICLES
init_particles_loop:
jsr init_particle
dex
bpl init_particles_loop
rts
hgr_draw_particles:
lda #0
sta HGR_COLOR
ldx #PARTICLES
clear_loop:
txa
pha
tay
ldx particle_x,Y
lda particle_y,Y
ldy #0
jsr HPLOT0 ; plot at (Y,X), (A)
pla
tax
dex
bpl clear_loop
; move particles
; draw particles
ldx #PARTICLES
draw_particles_loop:
; adjust x
lda particle_x,X
clc
adc particle_vx,X
sta particle_x,X
; bmi redo_particle
; cmp #40*SCALE
; bcs redo_particle
; adjust y
; first adjust for gravity
inc particle_vy,X
; inc particle_vy,X
lda particle_y,X
clc
adc particle_vy,X
sta particle_y,X
; bmi redo_particle
cmp #191
bcc y_good
redo_particle:
jsr init_particle
y_good:
dec particle_life,X
beq redo_particle
lda #$ff
sta HGR_COLOR
; lda particle_life,X
; sta HGR_COLOR
; sec
; sbc #$11
; sta particle_life,X
; cmp #$ef
; beq redo_particle
txa
pha
tay
ldx particle_x,Y
lda particle_y,Y
ldy #0
jsr HPLOT0 ; plot at (Y,X), (A)
pla
tax
dex
bpl draw_particles_loop
rts
HPLOT0:
; line from (x,a) to (x+y,a)
ldy #4
jsr hgr_hlin
rts
; init particle
; particle in X
init_particle:
; source
; lda #128 ; init x
ldy CURRENT_LEMMING
lda lemming_x,Y
asl
adc lemming_x,Y
asl
adc lemming_x,Y ; mul by 7
sta particle_x,X
lda lemming_y,Y
; lda #100 ; init y
sta particle_y,X
; color
lda #$ff
sta particle_life,X
; velocities
; -8 to 8?
jsr random
cmp #$80
ror
sta particle_vx,X
jsr random
ora #$f0
sta particle_vy,X
rts
; -8 to 8
; batari RNG
random:
lda SEEDHI
lsr
rol SEEDLO
bcc noeor
eor #$B4
noeor:
sta SEEDHI
eor SEEDLO
and #$f
sec
sbc #$8
rts