dos33fsprogs/graphics/hgr/plasma/moving.s
2021-11-04 21:39:42 -04:00

193 lines
2.8 KiB
ArmAsm

; Moving
; moving, orange and green
; zero page
GBASL = $26
GBASH = $27
YY = $69
ROW_SUM = $70
HGR_X = $E0
HGR_XH = $E1
HGR_Y = $E2
HGR_COLOR = $E4
HGR_PAGE = $E6
FRAME = $FC
SUM = $FD
SAVEX = $FE
SAVEY = $FF
; soft-switches
FULLGR = $C052
PAGE1 = $C054
; ROM routines
HGR2 = $F3D8
HPOSN = $F411 ; (Y,X),(A) (values stores in HGRX,XH,Y)
;================================
; Clear screen and setup graphics
;================================
oval:
jsr HGR2 ; set hi-res 140x192, page2, fullscreen
; A and Y both 0 at end
;==================
; create sinetable
;ldy #0 ; Y is 0
sinetable_loop:
tya ; 2
and #$3f ; wrap sine at 63 entries ; 2
cmp #$20
php ; save pos/negative for later
and #$1f
cmp #$10
bcc sin_left ; blt
sin_right:
; sec carry should be set here
eor #$FF
adc #$20 ; 32-X
sin_left:
tax
lda sinetable_base,X ; 4+
plp
bcc sin_done
sin_negate:
; carry set here
eor #$ff
; adc #0 ; FIXME: this makes things off by 1
sin_done:
sta sinetable,Y
iny
bne sinetable_loop
; NOTE: making gbash/gbasl table wasn't worth it
;============================
; main loop
;============================
draw_oval:
inc FRAME
lda #191 ; YY
create_yloop:
; HGR_Y (YY) is in A here
; ldx #39 ; X is don't care?
; ldy #0 ; Y is also don't care?
jsr HPOSN ; (Y,X),(A) (values stores in HGRX,XH,Y)
; restore values
lda HGR_Y ; YY
tax
calcsine_div4:
lsr
lsr ; 2
sec
sbc FRAME
tay
lda sinetable,y
sta row_sum_smc+1
; ldx HGR_Y ; YY
ldy #39 ; XX
create_xloop:
;=====================
; critical inner loop
; every cycle here is 40x192 cycles
;=====================
clc
tya
adc FRAME
tax
lda sinetable,X
adc sinetable,Y ; 4+
row_sum_smc:
adc #$dd ; row base value ; 2
lsr ; double colors ; 2
; also puts bit in carry
; which helps proper color gen
and #$7 ; 2
tax ; 2
lda colorlookup,X ; lookup in table ; 5
ror_nop_smc:
ror ; $6A/$EA ; 2
sta (GBASL),Y ; 6
lda ror_nop_smc ; toggle ror/nop ; 4
eor #$80 ; 2
sta ror_nop_smc ; 4
dey ; 2
bpl create_xloop ; 2/3
dec HGR_Y
lda HGR_Y
cmp #$ff ; blah want to draw line 0
bne create_yloop
flip_pages:
; Y should be $FF here
lda HGR_PAGE ; will be $20/$40
cmp #$20
bne done_page
dey
done_page:
ldx PAGE1-$FE,Y ; set display page to PAGE1 or PAGE2
eor #$60 ; flip draw page between $2000/$4000
sta HGR_PAGE
bne draw_oval ; bra
colorlookup:
.byte $22,$aa,$ba,$ff,$ba,$aa,$22 ; use 00 from sinetable
;.byte $00
;.byte $11,$55,$5d,$7f,$5d,$55,$11 ; use 00 from sinetable
;.byte $00
;sinetable_base = $F5BA
sinetable_base:
; this is actually (32*sin(x))
.byte $00,$03,$06,$09,$0C,$0F,$11,$14
.byte $16,$18,$1A,$1C,$1D,$1E,$1F,$1F
.byte $20
; for bot
; 3F5 - 7d = 378
; jmp oval
sinetable=$6000