second: finally got gorilla scroll working

this was much more of a pain than needed

demos/second/part08_gorilla/Makefile

@@ -17,7 +17,7 @@ GORILLA:	gorilla.o
 gorilla.o:	gorilla.s \
 	../zx02_optim.s \
 	../hgr_copy_fast.s \
-	tv_effect.s \
+	tv_effect.s horiz_scroll_simple.s \
 	../zp.inc ../hardware.inc ../qload.inc \
 	audio/a_pboy.btc.zx02 \
 	graphics/mntscrl3.hgr.zx02

demos/second/part08_gorilla/gorilla.s

@@ -50,18 +50,33 @@ gorilla_start:
 	sta	COUNT
 	sta	DRAW_PAGE
 
-	lda	#$60
-	jsr	hgr_copy
+	;=======================
+	; scroll in from right
+	;=======================
 
-	bit	PAGE1
+	bit	PAGE1			; draw on visible page
+					; flipping while scrolling is hard
+
+	jsr	horiz_scroll_left
+
+;	lda	#$60
+;	jsr	hgr_copy
+
+;	bit	PAGE1
+
+
+	;==============================
+	; todo, possibly flash at end?
+	;==============================
 
 gorilla_wait:
 	lda	#29
 	jsr	wait_for_pattern
 	bcc	gorilla_wait
 
-
-	; TODO: TV_shutoff effect
+	;======================
+	; TV_shutoff effect
+	;======================
 
 ;	lda	#0
 ;	jsr	hgr_page1_clearscreen
@@ -110,15 +125,17 @@ gorilla_done:
 	rts
 
 
-.align $100
+;.align $100
 	.include	"../wait_keypress.s"
 ;	.include	"../zx02_optim.s"
 ;	.include	"../hgr_table.s"
 	.include	"../hgr_clear_screen.s"
 	.include	"../hgr_copy_fast.s"
+	.include	"../hgr_page_flip.s"
 
 	.include	"tv_effect.s"
 	.include	"../irq_wait.s"
+	.include	"horiz_scroll_simple.s"
 
 gorilla_data:
 	.incbin "graphics/mntscrl3.hgr.zx02"

demos/second/part08_gorilla/horiz_scroll_simple.s

@@ -0,0 +1,99 @@
+	; no page flip currently, that's hard
+
+	; scrolls two at a time to preserve colors
+
+horiz_scroll_left:
+
+scroll_left_loop:
+
+	lda	#0
+	sta	COUNT
+
+scroll_left_outer_outer_loop:
+
+	ldx	#191				; end is 191
+
+scroll_left_outer_loop:
+
+	; high
+
+	lda	hposn_high,X
+	clc
+	adc	DRAW_PAGE
+	sta	hsl_smc1+2		; SMC1 = $2000+2
+	sta	hsl_smc2+2		; SMC2 = $2000
+	sta	hsl_smc4+2		; SMC4 = $2000
+	sta	hsl_smc6+2		; SMC6 = $2000
+
+	ora	#$40			; convert to $6000 range
+	sta	hsl_smc3+2		; SMC3 = $6000+COUNT
+	sta	hsl_smc5+2		; SMC5 = $6000+COUNT+1
+
+	;=========================
+	; low
+
+	lda	hposn_low,X
+	sta	hsl_smc2+1		; SMC2 = $2000
+	sta	hsl_smc4+1		; SMC4 = $2000
+	sta	hsl_smc6+1		; SMC6 = $2000
+
+	sta	hsl_smc1+1		; SMC1 = $2000+2
+	inc	hsl_smc1+1
+	inc	hsl_smc1+1
+
+	clc
+	adc	COUNT
+
+	sta	hsl_smc3+1		; SMC3 = $6000+COUNT
+
+	sta	hsl_smc5+1		; SMC5 = $6000+COUNT+1
+	inc	hsl_smc5+1
+
+	ldy	#0
+scroll_left_inner_loop:
+
+hsl_smc1:
+	lda	$2000+2,Y
+hsl_smc2:
+	sta	$2000,Y
+
+	iny
+	cpy	#38
+	bne	scroll_left_inner_loop
+
+	; get new data to scroll in
+
+hsl_smc3:
+	lda	$6000		; 6000+COUNT
+
+hsl_smc4:
+	sta	$2000,Y		; Y=38
+
+	iny
+
+hsl_smc5:
+	lda	$6000+1		; 6000+COUNT+1
+
+hsl_smc6:
+	sta	$2000,Y		; Y=39
+
+
+
+	dex
+	cpx	#$FF				; end at top of screen
+
+	bne	scroll_left_outer_loop
+
+;	jsr	hgr_page_flip
+
+	inc	COUNT
+	inc	COUNT
+	lda	COUNT
+	cmp	#40
+	bne	scroll_left_outer_outer_loop
+
+	rts
+
+
+
+