From f0a2779fe878c0474fa6c7162cf717c338cf44eb Mon Sep 17 00:00:00 2001
From: Vince Weaver <vince@deater.net>
Date: Sun, 17 Dec 2017 23:06:49 -0500
Subject: [PATCH] mode7_demo: add scrolling

---
 mode7_demo/Makefile          |   3 +-
 mode7_demo/deater_scroll.inc |  10 ++
 mode7_demo/mode7_demo.s      | 217 ++++++++++++++++++++++++++++++++++-
 3 files changed, 227 insertions(+), 3 deletions(-)
 create mode 100644 mode7_demo/deater_scroll.inc

diff --git a/mode7_demo/Makefile b/mode7_demo/Makefile
index f8113936..9cf70051 100644
--- a/mode7_demo/Makefile
+++ b/mode7_demo/Makefile
@@ -23,7 +23,8 @@ mode7_demo.o:	mode7_demo.s mode7_demo_backgrounds.inc \
 		../asm_routines/gr_unrle.s \
 		../asm_routines/hlin_clearscreen.s \
 		../asm_routines/gr_setpage.s \
-		../asm_routines/gr_fade.s
+		../asm_routines/gr_fade.s \
+		../asm_routines/gr_copy.s
 	ca65 -o mode7_demo.o mode7_demo.s -l mode7_demo.lst
 
 
diff --git a/mode7_demo/deater_scroll.inc b/mode7_demo/deater_scroll.inc
new file mode 100644
index 00000000..c234891b
--- /dev/null
+++ b/mode7_demo/deater_scroll.inc
@@ -0,0 +1,10 @@
+; Original size = 668 bytes
+deater_scroll:
+; scroll_length:
+.byte 167
+	.byte $A0,$28,$00,$20,$20,$A3,$00,$A4,$20,$00,$00,$20,$20,$00,$00,$A3,$20,$00,$A4,$20,$00,$A3,$20,$A7,$00,$40,$A3,$00,$40,$00,$00,$40,$40,$A3,$00,$A3,$40,$A6,$00,$10,$00,$00,$10,$00,$A4,$10,$00,$A3,$10,$00,$00,$A4,$10,$00,$A3,$10,$00,$A3,$10,$00,$A3,$10,$A0,$82,$00
+	.byte $A0,$28,$00,$E6,$00,$06,$E0,$00,$E6,$A4,$00,$E6,$00,$00,$E6,$00,$00,$E6,$00,$00,$E6,$A4,$00,$E6,$00,$00,$E6,$A6,$00,$DC,$A3,$00,$DC,$00,$DC,$00,$00,$DC,$00,$DC,$A9,$00,$B3,$00,$00,$B3,$00,$B3,$A4,$00,$B3,$00,$00,$B3,$00,$B3,$A4,$00,$03,$B3,$03,$00,$03,$B3,$03,$00,$03,$B3,$03,$A0,$82,$00
+	.byte $A0,$28,$00,$EF,$00,$00,$EF,$00,$EF,$0F,$0F,$00,$00,$EF,$0F,$0F,$EF,$00,$00,$EF,$00,$00,$EF,$0F,$0F,$00,$00,$EF,$0F,$0F,$E0,$A6,$00,$DF,$00,$D0,$00,$DF,$00,$DF,$0F,$0F,$DF,$00,$00,$0F,$0F,$D0,$A6,$00,$BF,$0F,$0F,$BF,$00,$BF,$0F,$0F,$00,$00,$BF,$0F,$0F,$B0,$00,$BF,$0F,$0F,$A3,$00,$0F,$A3,$00,$0F,$A3,$00,$0F,$A0,$83,$00
+	.byte $A0,$28,$00,$26,$20,$06,$00,$00,$26,$A3,$20,$00,$26,$00,$00,$26,$00,$00,$26,$00,$00,$26,$A3,$20,$00,$26,$00,$00,$26,$A6,$00,$4C,$0C,$00,$0C,$4C,$00,$4C,$00,$00,$4C,$00,$A3,$40,$0C,$A6,$00,$13,$00,$00,$13,$00,$13,$A3,$10,$00,$13,$00,$00,$13,$00,$13,$A3,$10,$00,$00,$13,$A3,$00,$13,$A3,$00,$13,$A0,$83,$00
+	.byte $A1
+; Compressed size = 294 bytes
diff --git a/mode7_demo/mode7_demo.s b/mode7_demo/mode7_demo.s
index efaa0ea8..bde9fca9 100644
--- a/mode7_demo/mode7_demo.s
+++ b/mode7_demo/mode7_demo.s
@@ -25,11 +25,30 @@
 
 demo_loop:
 
+	;==========
+	; Fade in
+	;==========
+
 	jsr	fade_in
 
-	lda	#255
-	jsr	WAIT
+	;==========================================
+	; Make sure page0 and page1 show same image
+	;==========================================
 
+	jsr	gr_copy_to_current
+
+	;===================
+	; Scroll the message
+	;===================
+
+;	lda	#255
+;	jsr	WAIT
+
+	jsr	scroll
+
+	;=============
+	; Fade out
+	;=============
 	jsr	fade_out
 
 
@@ -45,5 +64,199 @@ demo_loop:
 .include "../asm_routines/gr_setpage.s"
 .include "../asm_routines/pageflip.s"
 .include "../asm_routines/gr_fade.s"
+.include "../asm_routines/gr_copy.s"
 
 .include "mode7_demo_backgrounds.inc"
+
+
+scroll_row1	EQU     $8A00
+scroll_row2	EQU	$8B00
+scroll_row3	EQU	$8C00
+scroll_row4	EQU	$8D00
+
+SCROLL_LENGTH	EQU	$E6
+
+
+
+scroll:
+	lda	#0
+	sta	ANGLE
+
+	;=======================
+	; decompress scroll text
+	;=======================
+	lda	#>deater_scroll
+	sta	INH
+	lda	#<deater_scroll
+	sta	INL
+	jsr	decompress_scroll
+
+
+scroll_loop:
+
+	ldx	#0
+	ldy	ANGLE
+
+	lda	DISP_PAGE
+	beq	draw_page2
+
+	lda	#4
+	sta	sm1+2
+	sta	sm2+2
+	lda	#5
+	sta	sm3+2
+	sta	sm4+2
+	jmp	draw_done
+
+draw_page2:
+	lda	#8
+	sta	sm1+2
+	sta	sm2+2
+	lda	#9
+	sta	sm3+2
+	sta	sm4+2
+draw_done:
+
+draw_loop:
+
+	lda	scroll_row1,Y
+sm1:
+	sta	$400,X
+
+	lda	scroll_row2,Y
+sm2:
+	sta	$480,X
+
+	lda	scroll_row3,Y
+sm3:
+	sta	$500,X
+
+	lda	scroll_row4,Y
+sm4:
+	sta	$580,X
+
+	iny
+	inx
+	cpx	#40
+	bne	draw_loop
+
+	;==================
+	; flip pages
+	;==================
+
+	jsr	page_flip						; 6
+
+	;==================
+	; delay
+	;==================
+
+	lda	#125
+	jsr	WAIT
+
+
+	;==================
+	; loop forever
+	;==================
+	clc
+	lda	ANGLE
+	adc	#40
+	cmp	SCROLL_LENGTH
+	bne	blah
+	lda	#0
+	sta	ANGLE
+	jmp	scroll_loop
+
+blah:
+	inc	ANGLE
+	jmp	scroll_loop						; 3
+
+
+
+	;=======================
+	; decompress scroll
+	;=======================
+decompress_scroll:
+	ldy	#0
+	jsr	scroll_load_and_increment
+	sta	SCROLL_LENGTH
+
+	lda	#<scroll_row1
+	sta	OUTL
+	lda	#>scroll_row1
+	sta	OUTH
+
+decompress_scroll_loop:
+	jsr	scroll_load_and_increment	; load compressed value
+
+	cmp	#$A1			; EOF marker
+	beq	done_decompress_scroll	; if EOF, exit
+
+	pha				; save
+
+	and	#$f0			; mask
+	cmp	#$a0			; see if special AX
+	beq	decompress_scroll_special
+
+	pla				; note, PLA sets flags!
+
+	ldx	#$1			; only want to print 1
+	bne	decompress_scroll_run
+
+decompress_scroll_special:
+	pla
+
+	and	#$0f			; check if was A0
+
+	bne	decompress_scroll_color	; if A0 need to read run, color
+
+decompress_scroll_large:
+	jsr	scroll_load_and_increment	; get run length
+
+decompress_scroll_color:
+	tax				; put runlen into X
+	jsr	scroll_load_and_increment	; get color
+
+decompress_scroll_run:
+	sta	(OUTL),Y
+	pha
+
+	clc				; increment 16-bit pointer
+	lda	OUTL
+	adc	#$1
+	sta	OUTL
+	lda	OUTH
+	adc	#$0
+	sta	OUTH
+
+	pla
+
+	dex				; repeat for X times
+	bne	decompress_scroll_run
+
+	beq	decompress_scroll_loop	; get next run
+
+done_decompress_scroll:
+	rts
+
+
+scroll_load_and_increment:
+	lda	(INL),Y			; load and increment 16-bit pointer
+	pha
+	clc
+	lda	INL
+	adc	#$1
+	sta	INL
+	lda	INH
+	adc	#$0
+	sta	INH
+	pla
+	rts
+
+
+;===============================================
+; Variables
+;===============================================
+
+.include "deater_scroll.inc"
+
+