; Sierpinski, based on the code in Hellmood's Memories

; by deater (Vince Weaver) <vince@deater.net>

; Zero Page
GBASL		= $26
GBASH		= $27
H2		= $2C
MASK		= $2F
COLOR		= $30

BH		= $EF
Y1		= $F0
Y2		= $F1

NUM1L		= $F2
NUM1H		= $F3
NUM2L		= $F4
NUM2H		= $F5
RESULT0		= $F6
RESULT1		= $F7
RESULT2		= $F8
RESULT3		= $F9


TEMP		= $FA
TEMPY		= $FB
FRAMEL		= $FC
FRAMEH		= $FD
TEMPX		= $FE
SCALED		= $FF


; Soft Switches
KEYPRESS= $C000
KEYRESET= $C010
SET_GR	= $C050 ; Enable graphics
FULLGR	= $C052	; Full screen, no text
PAGE0	= $C054 ; Page0
PAGE1	= $C055 ; Page1
LORES	= $C056	; Enable LORES graphics

; ROM routines

PLOT	= $F800	; plot, horiz=y, vert=A (A trashed, XY Saved)
SETCOL	= $F864
TEXT	= $FB36				;; Set text mode
BASCALC	= $FBC1
SETGR	= $FB40
HOME	= $FC58				;; Clear the text screen
WAIT	= $FCA8				;; delay 1/2(26+27A+5A^2) us
HLINE	= $F819


sierpx	=	$3000
sierpy	=	$3100
scaledx	=	$3200
scaledy	=	$3300


sierpinksi:

	;===================
	; init screen
	jsr	SETGR				; 3
	bit	FULLGR				; 3

;	lda	#>(2048)
	lda	#0
	sta	FRAMEH
	lda	#0
	sta	FRAMEL

	jsr	init_multiply_tables

sierpinski_forever:


	inc	FRAMEL				; 2
	bne	done_frame_inc
	inc	FRAMEH
done_frame_inc:

	; pre-generate the multiplications
	jsr	sierpinski_generate

	ldx	#47		; yy		; 2


yloop:
	ldy	#39		; xx		; 2
xloop:

	; t=frame-2048 (assuming we are effect #4?)

;	lda	FRAMEL
;	sta	NUM1L

;	sec
;	lda	FRAMEH
;	sbc	#>(2048)

;	rol	NUM1L		; time<<=3, speed up by factor of 8
;	rol
;	rol	NUM1L
;	rol
;	rol	NUM1L
;	rol
;	sta	NUM1H

;	txa			; yy*=4
;	asl
;	asl
;	sta	NUM2L
;	sta	Y1
;	lda	#0
;	sta	NUM2H

;	jsr	multiply_u16x16		; result = Y*T

;	tya
;	asl
;	asl
;	sta	NUM2L
;	lda	#0
;	rol	NUM2L
;	rol
;	sta	NUM2H			; NUM2 = X*8

	; sign extend X

    ;    xsext=xprime*8;   // get X into DL
     ;   if (xsext&0x80*8) xsext|=0xff00*8;
      ;  else xsext&=0x00ff*8;

	clc
	lda	sierpy,X		; RESULT1
	adc	scaledx,Y		; NUM2L
	sta	BH			; bh=((y*t)/256)+X

;	jsr	multiply_u16x16_same_num1		; result = X*T
					; dh=RESULT1

    ;    dh=(temp>>8)&0xff;              // dh=(X*T/256)

     ;   color=(yy-dh)&bh;               // color=(Y-(X*T/256))&(Y*T/256+X)


	sec
	txa
	lda	scaledy,X		; Y1
	sbc	sierpx,Y		; RESULT1
	and	BH

	and	#$f8			; thicker sierpinksi

	; if zero, color=9.  Otherwise, 0

	bne	color_black		;  leave black if not sierpinksi
	lda	#$99			; otherwise: a nice orange
	bne	color_done
color_black:
	lda	#$00
color_done:

	sta	COLOR

	txa		; A==Y1			; 1
;	jsr	PLOT	; (X2,Y1)		; 3
	jsr	fast_plot

	dey					; 1
	bpl	xloop				; 2

	dex					; 1
	bpl	yloop				; 2

	bmi	sierpinski_forever		; 2


; for grabbing screenshot
;check_key:
;	bit	KEYPRESS
;	bpl	check_key
;	jmp	sierpinski_forever		; 2







sierpinski_generate:

	; t=frame-2048 (assuming we are effect #4?)

	lda	FRAMEL
	sta	NUM1L

;	sec
	lda	FRAMEH
;	sbc	#>(2048)

	rol	NUM1L		; time<<=3, speed up by factor of 8
	rol
	rol	NUM1L
	rol
	rol	NUM1L
	rol
	sta	NUM1H

	jsr	multiply_u16x16		; setup NUM1H/NUM1L

	;========================

	ldx	#47		; yy		; 2
genyloop:


	txa			; yy*=4
	asl
	asl
	sta	NUM2L
	sta	scaledy,X
	lda	#0
	sta	NUM2H

	jsr	multiply_u16x16_same_num1		; result = Y*T

	lda	RESULT1
	sta	sierpy,X

	dex					; 1
	bpl	genyloop				; 2

	;====================
	;====================
	;====================

	ldy	#39		; xx		; 2
genxloop:

	tya
	asl
	asl
	sta	NUM2L
	lda	#0
	rol	NUM2L
	rol
	sta	NUM2H			; NUM2 = X*8
	lda	NUM2L
	sta	scaledx,Y

	; sign extend X

    ;    xsext=xprime*8;   // get X into DL
     ;   if (xsext&0x80*8) xsext|=0xff00*8;
      ;  else xsext&=0x00ff*8;

	jsr	multiply_u16x16_same_num1		; result = X*T

	lda	RESULT1
	sta	sierpx,Y

	dey					; 1
	bpl	genxloop			; 2

	rts



.include "fast_plot.s"

.include "multiply_tables.s"
;.include "multiply_s16x16.s"
.include "multiply_u16x16_mod.s"

; original
; + plot is $5d cycles (93), so 178560 to draw screen
; + $169 (361) to calculate
; + 693120+178560 = 872k to draw screen (~1fps)

; with lookup table:
; + plot is $5d cycles (93), so 178560 to draw screen
; + $3a (58) to calculate
; + $2e5c (11,868) to setup tables
; + 111360+178560+11868=290k (~3fps)

; with lookup table+inline fast_plot
; + plot is $31 cycles (49), so 94080 to draw screen
; + $3a (58) to calculate
; + $2e5c (11,868) to setup tables
; + 111360+94080+11868=217k (~4fps)