dos33fsprogs/graphics/gr/plasma/plasma2.s
2021-10-16 21:30:06 -04:00

293 lines
4.3 KiB
ArmAsm

; more plasma
; by Vince `deater` Weaver (vince@deater.net) / dSr
; with some help from qkumba
; zero page
GBASL = $26
GBASH = $27
MASK = $2E
COLOR = $30
;CTEMP = $68
YY = $69
FRAME = $FC
SUM = $FD
SAVEX = $FE
SAVEY = $FF
; soft-switches
FULLGR = $C052
PAGE1 = $C054
; ROM routines
PLOT = $F800 ;; PLOT AT Y,A
PLOT1 = $F80E ;; PLOT at (GBASL),Y (need MASK to be $0f or $f0)
GBASCALC= $F847 ;; take Y-coord/2 in A, put address in GBASL/H ( a trashed, C clear)
SETCOL = $F864 ;; COLOR=A*17
SETGR = $FB40
;================================
; Clear screen and setup graphics
;================================
plasma:
jsr SETGR ; set lo-res 40x40 mode
bit FULLGR ; make it 40x48
draw_plasma:
; lda #$0f
; sta MASK
ldx #47 ; YY
create_yloop:
; lda MASK
; eor #$FF
; sta MASK
; txa
; lsr
; jsr GBASCALC ; take Y-coord/2 in A, put address in GBASL/H ( a trashed, C clear)
ldy #0
txa
jsr PLOT ; (Y,A) sets GBASL/GBASH, Y
ldy #39
create_xloop:
lda #128
sta SUM
tya ; XX
jsr calcsine_div2
txa ; YY
jsr calcsine
clc
sty SAVEY ; XX
txa
adc SAVEY ; XX + YY
jsr calcsine_div2
clc
adc FRAME
lsr
and #$7
tax
lda colorlookup,X
jsr SETCOL
ldy SAVEY
lda SAVEX
jsr PLOT1 ; PLOT (GBASL),Y
ldx SAVEX
dey
bpl create_xloop
dex
bpl create_yloop
; X and Y both $FF
create_lookup_done:
forever_loop:
inc FRAME
jmp draw_plasma
; jmp forever_loop
.if 0
cycle_colors:
; cycle colors
; instead of advancing entire frame, do slightly slower route
; instead now and just incrememnting the frame and doing the
; adjustment at plot time.
; increment frame
inc frame_smc+1
; set/flip pages
; we want to flip pages and then draw to the offscreen one
flip_pages:
; ldy #0
; iny ; y is $FF, make it 0
lda draw_page_smc+1 ; DRAW_PAGE
bne done_page
dey
done_page:
; ldx PAGE1,Y ; set display page to PAGE1 or PAGE2
ldx $BF56,Y ; PAGE1 - $FF
eor #$4 ; flip draw page between $400/$800
sta draw_page_smc+1 ; DRAW_PAGE
; plot current frame
; scan whole 40x48 screen and plot each point based on
; lookup table colors
plot_frame:
ldx #47 ; YY=47 (count backwards)
plot_yloop:
txa ; get YY into A
pha ; save X for later
lsr ; call actually wants Ycoord/2
php ; save C flag for mask handling
; ugh can't use PLOT trick as it always will draw something
; to PAGE1 even if we don't want to
jsr GBASCALC ; point GBASL/H to address in (A is ycoord/2)
; after, A is GBASL, C is clear
lda GBASH ; adjust to be PAGE1/PAGE2 ($400 or $800)
draw_page_smc:
adc #0
sta GBASH
; increment YY in top nibble of lookup for (yy<<16)+xx
; clc from above, C always 0
lda plot_lookup_smc+1
adc #$10 ; no need to mask as it will oflo and be ignored
sta plot_lookup_smc+1
;==========
ldy #39 ; XX = 39 (countdown)
; sets MASK by calling into middle of PLOT routine
; by Y being 39 draw in a spot that gets over-written
plp
jsr $f806
plot_xloop:
tya ; get XX & 0x0f
and #$f
tax
plot_lookup_smc:
lda lookup,X ; load lookup, (YY*16)+XX
clc
frame_smc:
adc #$00 ; add in frame
and #$f
lsr ; we actually only have 8 colors
tax
lda colorlookup,X ; lookup color
sta COLOR ; each nibble should be same
jsr PLOT1 ; plot at GBASL,Y (x co-ord goes in Y)
dey
bpl plot_xloop
pla ; restore YY
tax
dex
bpl plot_yloop
bmi forever_loop
.endif
;calcsine_div8:
; lsr
;calcsine_div4:
; lsr
calcsine_div2:
lsr
calcsine:
stx SAVEX
and #$3f
tax
rol
rol
rol
bcc sinadd
sinsub:
lda #0
lda SUM
; sec
sbc sinetable-32,X
jmp sindone
sinadd:
lda SUM
; clc
adc sinetable,X
sindone:
sta SUM
ldx SAVEX
rts
colorlookup:
; blue
;.byte $55,$22,$66,$77,$ff,$77,$55,$00
.byte $00,$55,$77,$ff,$77,$66,$22,$55
;.byte $00,$00,$55,$55,$77,$77,$ff,$ff
;.byte $77,$77,$66,$66,$22,$22,$55,$55
sinetable:
; 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,$1F,$1F,$1E,$1D,$1C,$1A,$18
.byte $16,$14,$11,$0F,$0C,$09,$06,$03
;.byte $00,$FD,$FA,$F7,$F4,$F1,$EF,$EC
;.byte $EA,$E8,$E6,$E4,$E3,$E2,$E1,$E1
;.byte $E0,$E1,$E1,$E2,$E3,$E4,$E6,$E8
;.byte $EA,$EC,$EF,$F1,$F4,$F7,$FA,$FD
;.byte $00,$06,$0C,$11,$16,$1A,$1D,$1F
;.byte $20,$1F,$1D,$1A,$16,$11,$0C,$06
;.byte $00,$FA,$F4,$EF,$EA,$E6,$E3,$E1
;.byte $E0,$E1,$E3,$E6,$EA,$EF,$F4,$FA
;.byte $00,$0C,$16,$1D
;.byte $20,$1D,$16,$0C
;.byte $00,$F4,$EA,$E3
;.byte $E0,$E3,$EA,$F4