From e45baa57b0a95a1e45e52efbe09a98c31719c530 Mon Sep 17 00:00:00 2001
From: alpine9000 <alex.g.brown@gmail.com>
Date: Tue, 12 Apr 2016 16:27:05 +1000
Subject: [PATCH] Test dual scroll

---
 027.game1/Makefile       | 14 +++----
 027.game1/blit.s         |  4 +-
 027.game1/image.s        |  8 ++--
 027.game1/scroll.s       | 48 +++++++++++++++---------
 027.game1/tile_hscroll.s | 79 ++++++++++++++++++++++++++++++++--------
 5 files changed, 107 insertions(+), 46 deletions(-)

diff --git a/027.game1/Makefile b/027.game1/Makefile
index 305e1cc..d9497c2 100644
--- a/027.game1/Makefile
+++ b/027.game1/Makefile
@@ -11,9 +11,9 @@ NUM_COLORS=8
 BOOTBLOCK_ASM=alpine_bootblock.s
 OBJS=out/init.o out/utils.o out/image.o out/blit.o out/scroll.o
 
-#IMAGES=gigi_full.png
-#IMAGEDATA=$(addprefix out/, $(IMAGES:.png=.bin))
-#SIZEDIMAGEDATA=$(addprefix out/, $(IMAGES:.png=.sized.png))
+IMAGES=gigi_full.png
+IMAGEDATA=$(addprefix out/, $(IMAGES:.png=.bin))
+SIZEDIMAGEDATA=$(addprefix out/, $(IMAGES:.png=.sized.png))
 
 TILEMAPS=2222.png background_tiles.png
 TILEMAPDATA=$(addprefix out/, $(TILEMAPS:.png=.bin))
@@ -26,11 +26,11 @@ LINKER_OPTIONS=-T link.script.x
 include ../shared/base.mk
 
 
-#out/%.sized.png: ../assets/%.png
-#	$(RESIZE) --width=352 --height=256 --blur=0.75 --input=$< --output=$@
+out/%.sized.png: ../assets/%.png
+	$(RESIZE) --width=352 --height=256 --blur=0.75 --input=$< --output=$@
 
-#out/%.bin: out/%.sized.png
-#	$(IMAGECON) --input $< $(IMAGECON_ARGS) --quantize --colors $(NUM_COLORS) --output-bitplanes  --output-palette-asm --output-grey-palette --output-palette $(DITHER) --output out/$*
+out/%.bin: out/%.sized.png
+	$(IMAGECON) --input $< $(IMAGECON_ARGS) --quantize --colors $(NUM_COLORS) --output-bitplanes  --output-palette-asm --output-grey-palette --output-palette $(DITHER) --output out/$*
 
 out/%.bin: assets/%.png
 	$(IMAGECON) --use-palette=assets/fg.pal --input $< $(IMAGECON_ARGS) --quantize --colors $(NUM_COLORS) --output-bitplanes  --output-palette --full-color-palette-file --output-palette-asm --output-grey-palette --output-palette $(DITHER) --output-png --output out/$*
diff --git a/027.game1/blit.s b/027.game1/blit.s
index 1b021e8..a59735d 100644
--- a/027.game1/blit.s
+++ b/027.game1/blit.s
@@ -106,7 +106,7 @@ BlitTile:
 	;; d2 - y tile index
 
 	WaitBlitter
-	movem.l	d2,-(sp)
+	movem.l	d0-a6,-(sp)
 	move.w	#0,BLTCON1(a6)		;
 	move.w	#BC0F_SRCA|BC0F_DEST|$f0,BLTCON0(a6)
 	
@@ -121,7 +121,7 @@ BlitTile:
 	move.w	#$ffff,BLTAFWM(a6)
 	move.w	#$ffff,BLTALWM(a6)
 	move.w 	#(16*SCREEN_BIT_DEPTH)<<6|(1),BLTSIZE(a6)	;rectangle size, starts blit
-	movem.l	(sp)+,d2
+	movem.l	(sp)+,d0-a6
 	rts
 
 
diff --git a/027.game1/image.s b/027.game1/image.s
index 0aa1cc7..a4dd488 100644
--- a/027.game1/image.s
+++ b/027.game1/image.s
@@ -1,10 +1,11 @@
 	include "includes.i"
 
 	xdef SwitchBuffers
-		
+	
 SwitchBuffers:
 	;; offscreen - bitplane address
-	;; d0 - bitplane pointer offset
+	;; d0 - fg bitplane pointer offset
+	;; d1 - bg bitplane pointer offset
 	movem.l	d0/a0-a1,-(sp)
 	move.l	offscreen,a0
 	move.l	onscreen,offscreen
@@ -14,8 +15,9 @@ SwitchBuffers:
 	jsr	PokeBitplanePointers
 
 
-	lea	backgroundTiles,a1
+	lea	bg_bitplanes,a1
 	lea 	copperListBpl2Ptr,a0
+	move.l	d1,d0
 	jsr	PokeBitplanePointers	
 	movem.l (sp)+,d0/a0-a1
 	rts
diff --git a/027.game1/scroll.s b/027.game1/scroll.s
index 0977478..a9958db 100644
--- a/027.game1/scroll.s
+++ b/027.game1/scroll.s
@@ -3,28 +3,40 @@
 	xdef HoriScrollPlayfield
 	
 HoriScrollPlayfield:
-	;; d0 - x position in pixels
+	;; d0 - fg x position in pixels
+	;; d1 - bg x position in pixels	
 	;; out:
-	;; d0 - bitplane pointer increment in bytes
-	movem.l	d1-a6,-(sp)
-	move.l	d0,d1
+	;; d0 - fg bitplane pointer increment in bytes
+	;; d1 - bg bitplane pointer increment in bytes	
+	movem.l	d2-a6,-(sp)
+
+	move.l	d0,d3
+	move.l	d1,d0
+	
+	move.l	d1,d2
+	lsr.l   #3,d0		; bytes to scroll
+	move.l  d0,d4		; save bitplane pointer increment (bytes) for return value
+	and.l   #$F,d2		; pixels = 0xf - (hpos - (hpos_bytes*8))
+	move.l  #$F,d0
+	sub.l   d2,d0		; bits to delay	
+	move.l	d0,d5		; d5 == bg bits to delay
+
+	move.l	d3,d0
+	move.l	d0,d2
 	lsr.l   #3,d0		; bytes to scroll
 	move.l  d0,d3		; save bitplane pointer increment (bytes) for return value
-	and.l   #$F,d1		; pixels = 0xf - (hpos - (hpos_bytes*8))
+	and.l   #$F,d2		; pixels = 0xf - (hpos - (hpos_bytes*8))
 	move.l  #$F,d0
-	sub.l   d1,d0		; bits to delay	
-	bsr	SetupHoriScrollBitDelay
-	move.l	d3,d0		; retstore d0 for return value
-	movem.l (sp)+,d1-a6
+	sub.l   d2,d0		; bits to delay
+
+	lsl.w	#4,d5
+	or.w	d5,d0	
+
+	move.w  d0,BPLCON1(a6)	
+	
+	move.l	d3,d0		; restore d0 for return value
+	move.l	d4,d1		; restore d1 for return value
+	movem.l (sp)+,d2-a6
 	rts
 
-SetupHoriScrollBitDelay:
-	;; d0 = number of bits to scroll
-	movem.l	d0/d1,-(sp)
-	move.w	d0,d1
-	;; lsl.w	#4,d1
-	;; 	or.w	d1,d0
-	move.w  d0,BPLCON1(a6)
-	movem.l (sp)+,d0/d1
-	rts
 	
\ No newline at end of file
diff --git a/027.game1/tile_hscroll.s b/027.game1/tile_hscroll.s
index 3df263b..7de5cf1 100644
--- a/027.game1/tile_hscroll.s
+++ b/027.game1/tile_hscroll.s
@@ -6,6 +6,7 @@
 	xdef	copperListBpl1Ptr
 	xdef	copperListBpl2Ptr	
 	xdef    backgroundTiles
+	xdef 	bg_bitplanes
 	
 byteMap:
 	dc.l	Entry
@@ -23,6 +24,10 @@ Entry:
 	lea	Level3InterruptHandler,a3
  	move.l	a3,LVL3_INT_VECTOR			
 
+	;; d0 - fg bitplane pointer offset
+	;; d1 - bg bitplane pointer offset
+	move.l	#0,d0
+	move.l	#1,d1
 	jsr	SwitchBuffers		
 	
 	move.w	#(INTF_SETCLR|INTF_VERTB|INTF_INTEN),INTENA(a6)	
@@ -31,36 +36,42 @@ Entry:
 	jsr	Init		  ; enable the playfield		
 
 Reset:
-	move.l	#0,d1 			; x pos 
-	move.l	#0,d2			; shift counter
-	move.l	#0,d3			; tile index
-
+	move.l	#0,fg_xpos		; x pos 	(d1)
+	move.l	#0,fg_shift		; shift counter (d2)
+	move.l	#0,fg_tileIndex		; tile index	(d3)
+	move.l	#0,bg_xpos
+	
 	jsr 	BlueFill
 	
-MainLoop:		
-	jsr 	WaitVerticalBlank
+MainLoop:
+	add.l	#1,fg_xpos
 	jsr	WaitVerticalBlank
-
+	jsr 	WaitVerticalBlank
 	bsr	RenderNextFrame
 	jsr	UpdateShiftCounter
-	add.l	#1,d1
+	jsr 	UpdateBackgroundXpos
+	
+	;; d0 - fg bitplane pointer offset
+	;; d1 - bg bitplane pointer offset
+
 	jsr 	SwitchBuffers	    ; takes bitplane pointer offset in d0
 	bra	MainLoop
 	
 RenderNextFrame:
-	move.l	d1,d0		    ; x position in pixels
+	move.l	fg_xpos,d0		    ; fg x position in pixels
+	move.l	bg_xpos,d1		    ; bg x position in pixels
 	lea	map,a2
-	add.l	d3,a2
+	add.l	fg_tileIndex,a2
 	cmp.w	#0,20(a2)
 	bne	.skip
 	bra	Reset
 .skip:
-	jsr 	HoriScrollPlayfield ; returns bitplane pointer offset in d0	
+	jsr 	HoriScrollPlayfield ; returns fg bitplane pointer offset in d0		
 	move.l	onscreen,a0
 	bsr	RenderTile
 	move.l	offscreen,a0
 	bsr	RenderTile
-	add.l	#2,d3			; increment tile index
+	add.l	#2,fg_tileIndex    	  ; increment tile index
 	rts
 	
 RenderTile:
@@ -70,18 +81,30 @@ RenderTile:
 	lea 	tilemap,a1	
 	add.l	#BITPLANE_WIDTH_BYTES-2,a0 ; dest
 	add.w	(a2),a1 	; source tile
+	move.l	fg_shift,d2
 	jsr	BlitTile
 	rts
 	
 UpdateShiftCounter:	
-	cmp.l	#15,d2	
-	bne	.s1	
-	move.l	#0,d2
+	cmp.l	#15,fg_shift	
+	bne	.s1
+	move.l	#0,fg_shift
 	bra	.s2
 .s1:
-	add.l	#1,d2
+	add.l	#1,fg_shift
 .s2:
 	rts
+
+UpdateBackgroundXpos:	
+	cmp.l	#1,bg_delay
+	bne	.s1
+	move.l	#0,bg_delay
+	add.l	#1,bg_xpos
+	bra	.s2
+.s1:
+	add.l	#1,bg_delay
+.s2:
+	rts	
 	
 Level3InterruptHandler:
 	movem.l	d0-a6,-(sp)
@@ -162,6 +185,9 @@ bitplanes1:
 bitplanes2:
 	ds.b	IMAGESIZE
 	ds.b	BITPLANE_WIDTH_BYTES*20
+
+bg_bitplanes:
+	incbin	"out/gigi_full.bin"
 	
 map:
 	include "out/main-map.s"
@@ -170,7 +196,28 @@ map:
 backgroundTiles:
 	include "out/background_tiles.bin"
 	
+
+fg_shift:
+	dc.l	0
+fg_xpos:
+	dc.l	0
+fg_tileIndex:
+	dc.l	0
+
+bg_shift:
+	dc.l	0
+bg_xpos:
+	dc.l	0
+bg_tileIndex:
+	dc.l	0
+
+bg_delay:
+	dc.l	0
+	
 	section .bss
+
+
+
 startUserstack:
 	ds.b	$1000		; size of stack
 userstack: