dos33fsprogs/graphics/gr/bubble_universe/bubble_tiny.s

; bubble universe tiny -- Apple II Lores

; what if you zoom into a bubble universe and it's full of
; angry bees

; by Vince `deater` Weaver

; this version based on fast c64 code by serato_fig
;	as posted to the sizecoding discord
;	based on his TIC-80 variant

; originally was working off the BASIC code posted on the pouet forum
; original effect by yuruyrau on twitter

; 578 bytes = original color
; 531 bytes = remove keyboard code
; 527 bytes = inline sine gen
; 523 bytes = optimize init a bit
; 301 bytes = generate color lookup table
; 297 bytes = optimize color lookup table
; 282 bytes = optimize color shift
; 266 bytes = reduce resolution of sine table x2
; 260 bytes = shave off some bytes with unneeded compares
; 255 bytes = reoptimize the sine doubler
; 264 bytes = add sound (urgh)
; 265 bytes = fix colors
; 263 bytes = waste a lot of time optimizing color lookup table
; 259 bytes = undo self modifying code
; 247 bytes = remove extra cosine table
; 245 bytes = minor fixes
; 268 bytes = back to 64 byte lookup
; 264 bytes = optimize sine/cosine init
; 262 bytes = optimize var init
; 259 bytes = use sine_base in place

; soft-switches

SPEAKER		= $C030
FULLGR		= $C052

; ROM routines

PLOT    = $F800                 ;; PLOT AT Y,A
SETGR   = $FB40

; zero page

COLOR		= $30

SINES_BASE	= $C0

I		= $D0
J		= $D1
T		= $D7
U		= $D8
V		= $D9
IS		= $DA
IT		= $DB

INL		= $FC
INH		= $FD

;sines	= $6c00
;sines2	= $6d00
;cosines = $6cc0

sines	= sines_base
sines2	= sines_base+$100
cosines = sines_base+$c0


color_map = $1000

bubble_gr:

	;=======================
	; init graphics
	;=======================

	jsr	SETGR

	; can't rely on registers after this as different on IIe
	;	with 80 col card

	bit	FULLGR

	;========================
	; setup lookup tables
	;========================

	;========================
	; color lookup
	;========================
	; 34 original
	; 30 updated
	; 31 fixed
	; 29 improved


	;================
	; current best

	ldx	#0	; init output pointer		; 2
first_loop:
	ldy	#$ff	; reset current value		; 2
loop1:
yloop:
	iny						; 1
yloop2:
	tya						; 1
	sta	color_map,X	; values[y]=a;		; 3

	iny						; 1
	inx						; 1
	beq	done					; 2
	cpx	#16					; 2
	beq	first_loop				; 2

	txa						; 1
	and	#$f					; 2

	beq	yloop	; if nextcol==0, skip f->0	; 2

	lsr						; 1

	bne	yloop2	; if nextcol!=1, y=y+1		; 2

	dey		; if nextcol==1, repeat y	; 1
	jmp	yloop2					; 3

done:

	; X=0 here

	;=======================
	; init variables
	;=======================
	; wipe all of zero page
	;	we only care about one value, the color at $30

	txa
init_loop:
;	sta	a:$D0,X		; force 16-bit so doesn't wrap
				; because I guess it's bad to wipe zero page?
				; maybe it isn't?

	sta	$D0,X
	dex
	bne	init_loop

;	lda	#0
;	stx	U
;	stx	V
;	stx	T
;	stx	INL

	; X = 0 here

	;==========================
	; make sine/cosine tables
	;==========================

	; floor(s*sin((x-96)*PI*2/256.0)+48.5);

	;===================================
	;
	;
	; final_sine[i]=quarter_sine[i];          // 0..64
	; final_sine[128-i]=quarter_sine[i];      // 64..128
	; final_sine[128+i]=0x60-quarter_sine[i]; // 128..192
	; final_sine[256-i]=0x60-quarter_sine[i]; // 192..256

setup_sine_table:

	ldx	#64
	ldy	#64
setup_sine_loop:

	lda	sines_base,X

;	sta	sines,X
	sta	sines,Y

	lda	#$60
	sec
	sbc	sines_base,X

	sta	sines+128,X
	sta	sines+128,Y

	iny
	dex
	bpl	setup_sine_loop

	; X is $FF here?

	stx	COLOR			; $FF (color white)


	;=======================
	; double the sine table
	; used for cosine

;	ldx	#0
looper:
	lda	sines,X
	sta	sines2,X
	dex
	bne	looper

	; X is 0 here?



	;=========================
	;=========================
	; main loop
	;=========================
	;=========================

	; in theory Y=0 from previous loop, but not init above?

next_frame:

	; reset I*T

	lda	T
	sta	IT

	; reset I*S

	lda	#0
	sta	IS

	lda	#13	; 13
	sta	I

i_loop:
	lda	#$18	; 24
	sta	J
j_loop:

	bit	SPEAKER		; click speaker

	; where S=41 (approximately 1/6.28)
	; calc:	a=i*s+v;
	; calc:	b=i+t+u;
	; 	u=sines[a]+sines[b];
	; 	v=cosines[a]+cosines[b];

	clc			; 2
	lda	IS
	adc	V
	tay

	clc
	lda	IT
	adc	U
	tax

	clc
	lda	cosines,Y	; 4+
	adc	cosines,X	; 4+
	sta	V

	lda	sines,Y		; 4+
	adc	sines,X		; 4+
	sta	U		; 3

	bit	SPEAKER		; click speaker

	;===========================================================
	; original code is centered at 96,96 (on hypothetical 192x192 screen)

	; we adjust to be 40x48 window centered at 48,48

	; PLOT U-48,V-48

	; U already in A
;	sec
	sbc	#48
	tay								; 2
	cpy	#40
	bcs	no_plot

	; calculate Ypos
	lda	V
;	sec
	sbc	#48
	cmp	#48
	bcs	no_plot


	bit	SPEAKER		; click speaker

	jsr	PLOT		; PLOT AT Y,A

no_plot:
	dec	J
	bne	j_loop

done_j:
	clc
	lda	IS
	adc	#41		; 1/6.28 = 0.16 =  0 0    1   0       1 0 0 0 = 0x28
	sta	IS
	dec	I
	bne	i_loop
done_i:
	inc	T

end:

	;=================
	; cycle colors

	ldy	#$0				; 2
	lda	#4				; 2
	sta	INH				; 2
cycle_color_loop:
	lda	(INL),Y				; 2
	tax					; 1
	lda	color_map,X			; 3
	sta	(INL),Y				; 2

	iny					; 1
	bne	cycle_color_loop		; 2

	; need to do this for pages 4-7

	inc	INH				; 2
	lda	INH				; 2
	cmp	#$8				; 2
	bne	cycle_color_loop		; 2
	beq	next_frame	; bra		; 2



sines_base:
        .byte $30,$31,$32,$33,$34,$35,$36,$37,$38,$39,$3A,$3B,$3C,$3D,$3E,$3F
        .byte $40,$41,$42,$42,$43,$44,$45,$46,$47,$48,$48,$49,$4A,$4B,$4C,$4C
        .byte $4D,$4E,$4E,$4F,$50,$50,$51,$52,$52,$53,$53,$54,$54,$55,$55,$55
        .byte $56,$56,$57,$57,$57,$58,$58,$58,$58,$58,$59,$59,$59,$59,$59,$59
        .byte $59

; floor(s*cos((x-96)*PI*2/256.0)+48.5);