Groundwork for graphical loading screen

GSCats.xcodeproj/project.pbxproj

@@ -15,10 +15,10 @@
 		700F72872112428D00225B17 /* RenumberSpriteFiles.sh */ = {isa = PBXFileReference; lastKnownFileType = text.script.sh; path = RenumberSpriteFiles.sh; sourceTree = "<group>"; };
 		701E708A2A649A230030C35D /* tinyNumbers.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = tinyNumbers.s; sourceTree = "<group>"; };
 		701E708B2A660CEB0030C35D /* progressBar.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = progressBar.s; sourceTree = "<group>"; };
+		701E708E2A67844B0030C35D /* loaderGraphics.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = loaderGraphics.s; sourceTree = "<group>"; };
 		705456862A43E03B00A2B866 /* GeneratePixelCircle.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = GeneratePixelCircle.py; sourceTree = "<group>"; };
 		705456882A4D336200A2B866 /* animation.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = animation.s; sourceTree = "<group>"; };
 		7059502B1F37A0BE00BBE90F /* GenerateVRAMTable.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = GenerateVRAMTable.py; sourceTree = "<group>"; };
-		705AAFA920040B0D001BB0ED /* terrain_e1.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = terrain_e1.s; sourceTree = "<group>"; };
 		705C54E62124B7F300515A6B /* fan.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = fan.s; sourceTree = "<group>"; };
 		706DF1641F2D39F700AA6680 /* loader.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = loader.s; sourceTree = "<group>"; };
 		706DF1651F2D4A8100AA6680 /* terrain.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = terrain.s; sourceTree = "<group>"; };
@@ -58,14 +58,15 @@
 			children = (
 				70E9D85F1F2BD95400555C19 /* equates.s */,
 				700F21DE1F43E31300D7007D /* input.s */,
+				706DF1641F2D39F700AA6680 /* loader.s */,
+				701E708E2A67844B0030C35D /* loaderGraphics.s */,
+				70E9D8611F2BD95400555C19 /* gscats.s */,
 				70E9D8601F2BD95400555C19 /* graphics.s */,
 				70E9D8621F2BD95400555C19 /* macros.s */,
 				7099E3841F41022100182A82 /* gameobject.s */,
 				70F011D123B989B800C8873F /* random.s */,
-				706DF1641F2D39F700AA6680 /* loader.s */,
 				706DF1651F2D4A8100AA6680 /* terrain.s */,
 				701E708B2A660CEB0030C35D /* progressBar.s */,
-				705AAFA920040B0D001BB0ED /* terrain_e1.s */,
 				70F011D023B91B2900C8873F /* dirt.s */,
 				70C073091F5BAA3E009844A9 /* collision.s */,
 				70F086A01F4230CB002446C3 /* utility.s */,
@@ -81,7 +82,6 @@
 				708D1B1E27B9A1A600909AFC /* crosshair.s */,
 				70A80FB01F43D7F200BD34C9 /* gamemanager.s */,
 				70E554C41F807ADB00F3C871 /* spritebank.s */,
-				70E9D8611F2BD95400555C19 /* gscats.s */,
 				70E9D8631F2BD95400555C19 /* Makefile */,
 				70BDCBC92006AD5F00CB51F1 /* linkerConfig */,
 				701E708A2A649A230030C35D /* tinyNumbers.s */,

Makefile

@@ -14,13 +14,13 @@ VOLNAME=GSAPP
 IMG=DiskImageParts
 EMU=/Applications/GSplus.app/Contents/MacOS/gsplus
 ADDR=0800
+
 CODEBANK=CODEBANK\#060000
-CODEBANKE1=CODEBANKE1\#060800
 EXEC=$(PGM)\#06$(ADDR)
 SOUNDBANK=SOUNDBANK\#060000
 FONTBANK=FONTBANK\#060000
-
 PGM=gscats
+
 MRSPRITE=../MrSprite/mrsprite
 GENART=Art/Generated
 GENSOUND=Sound/Generated
@@ -29,9 +29,9 @@ PALETTE=a4dffb a4dffb 008800 886611 cc9933 eebb44 dd6666 ff99aa 777777 ff0000 b7
 SPRITES=SpriteBank
 SPRITEBANK=$(SPRITES)\#060000
 FLIPLIST=$(wildcard Art/*Fan.gif) $(wildcard Art/*Spit*.gif)
-REMOTESYMBOLS=-Wl $(shell ./ParseMapFile.py *.map)
+REMOTESYMBOLS= # -Wl $(shell ./ParseMapFile.py *.map)			<- Use this to share symbols across code banks
 
-all: clean diskimage terrain_e1 fonts $(PGM) loader emulate
+all: clean diskimage fonts $(PGM) loader emulate
 
 emulate:
 	# Leading hypen needed because GSPlus maddeningly returns code 1 (error) always and for no reason
@@ -51,11 +51,9 @@ $(PGM):
 	$(CAD) ADDFILE $(PGM).2mg /$(VOLNAME) $(SPRITEBANK)
 	$(CAD) ADDFILE $(PGM).2mg /$(VOLNAME) $(SOUNDBANK)
 	$(CAD) ADDFILE $(PGM).2mg /$(VOLNAME) $(FONTBANK)
-
 	rm -f $(CODEBANK)
 	rm -f $(FONTBANK)
 	rm -f $(PGM).o
-	rm -f terrain_e1.map
 	
 loader:
 	@PATH=$(PATH):/usr/local/bin; $(CL65) -t apple2enh --cpu 65816 --start-addr $(ADDR) -lloader.lst loader.s -o $(EXEC)
@@ -63,12 +61,6 @@ loader:
 	rm -f $(EXEC)
 	rm -f loader.o
 
-terrain_e1:
-	@PATH=$(PATH):/usr/local/bin; $(CL65) -t apple2enh -C linkerConfig --cpu 65816 --start-addr $(ADDR) -l -vm -m terrain_e1.map terrain_e1.s -o $(CODEBANKE1)
-	$(CAD) ADDFILE $(PGM).2mg /$(VOLNAME) $(CODEBANKE1)
-	rm -f $(CODEBANKE1)
-	rm -f terrain_e1.o
-
 fonts:
 	rm -rf $(FONTBANK)
 	./CompileFont.py 4 5 48 0 "tinyNum" "Art/Assets/TinyNumbers.gif" > fonts.s
@@ -82,9 +74,6 @@ clean:
 	rm -f $(PGM).o
 	rm -f loader
 	rm -f loader.o
-	rm -f terrain_e1.o
-	rm -f terrain_e1.map
-	rm -f terrain_e1
 	rm -f Art/*m.gif
 	rm -f $(GENART)/*
 	rm -f $(PGM).2mg

equates.s

@@ -13,6 +13,8 @@ VRAMBANK		= $e10000
 SHADOWVRAMBANK	= $010000
 PRODOS			= $bf00		; MLI entry point
 PRODOSRETURN	= $300		; Indirect jump to get back to ProDOS from any bank
+BORDERCOLORCACHE= $304		; Save system border color so we can put it back
+TEXTCOLORCACHE 	= $306		; Save system text colors so we can put it back
 
 ENSONIQ_CONTROL = $e1c03c		; Ensoniq-related registers/locations
 ENSONIQ_DATA = $e1c03d

gscats.s

@@ -22,11 +22,6 @@ mainBank2:
 	sta TEXTCOLOR
 	BITS16	
 
-	; Set up video
-	jsr initSCBs
-	SHRVIDEO
-	SHADOWMEMORY
-
 	jmp beginGameplay
 
 quitGame:

loader.s

@@ -6,6 +6,9 @@
 ;  Created by Quinn Dunki on 7/29/17
 ;
 
+.a16
+.i16
+
 .include "equates.s"
 .include "macros.s"
 
@@ -15,8 +18,48 @@ MAINENTRY = $020000
 
 .org $800
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; BORDER_COLOR
+;
+; Trashes A
+;
+.macro BORDER_COLOR color
+	SAVE_AXY
+	BITS8
+	lda BORDERCOLOR
+	and #$f0
+	ora color
+	sta BORDERCOLOR
+	BITS16
+	RESTORE_AXY
+.endmacro
+
+
 main:
-	OP8		; We launch in emulation. Stay there for now
+	BITS16
+	NATIVE
+	SHRVIDEO
+	SHADOWMEMORY
+	
+	; Cache system colors
+	BITS8
+	lda BORDERCOLOR
+	sta BORDERCOLORCACHE
+	lda TEXTCOLOR
+	sta TEXTCOLORCACHE
+	BITS16
+
+	; Throw up a loading screen
+	lda #loaderPalette
+	sta PARAML0
+	lda #0
+	jsr setPalette
+;	jsr initSCBs
+	BORDER_COLOR #$7
+	lda #$1111
+	jsr slowColorFill
+	
+	EMULATION
 
 	; Open the main code file
 	jsr PRODOS
@@ -50,6 +93,11 @@ main:
 	.byte $cc
 	.addr fileClose
 
+	bra mainContinue
+ioError:
+	brk
+
+mainContinue:
 	NATIVE
 
 	; Copy rest of code into bank 2 (needed if code size exceeds BUFFERSIZE)
@@ -60,59 +108,6 @@ main:
 
 	EMULATION
 
-;;;;;;;;;;;;;;;;;;;;;
-
-	; Open the E1 code file
-	jsr PRODOS
-	.byte $c8
-	.addr fileOpenCodeE1
-	bne ioError
-
-	; Load the code into bank 0
-	jsr PRODOS
-	.byte $ca
-	.addr fileRead
-	bne ioError
-
-	; Close the file
-	jsr PRODOS
-	.byte $cc
-	.addr fileClose
-
-	jmp loadData
-	; Note that we skip E1 code bank loading now. This was used for the
-	; fill mode terrain renderer, which is disabled until further notice
-	; There isn't enough safe room in E1 to do everything we wanted and the fill
-	; mode rendering isn't useful enough to keep
-
-	NATIVE
-
-	; Copy code into bank E1
-	ldx fileReadLen
-	lda #$E1
-	ldy #$800		; Must match terrain_e1 .org
-	jsr copyBytes
-
-
-	; Copy vram table into bank E1
-	; Note that there's a GS memory manager jump table at 1680 - 16BB
-	; in E1 that we have to work around. If we step on it, warm reboots and other
-	; critical things start to fail.
-	phb
-	lda #vramRowInvertedSpanLookupEnd-vramRowInvertedSpanLookup-1
-	ldx #vramRowInvertedSpanLookupEnd-1
-	ldy #$16C0 + vramRowInvertedSpanLookupEnd-vramRowInvertedSpanLookup-1 		; Must match terrain_e1 vramRowInvertedSpanLookup
-	mvp $e1,$00		; Note that ca65 reverses src,dest. Grrr.
-	plb
-
-	EMULATION
-
-
-ioError:
-	brk
-
-;;;;;;;;;;;;;;;;;;;;;
-loadData:
 	; Open the sprite bank file
 	jsr PRODOS
 	.byte $c8
@@ -242,26 +237,22 @@ loadData:
 returnToProDOS:
 	SYNCDBR
 	EMULATION
+
+	; Restore system colors
+	lda BORDERCOLOR
+	and #$f0
+	ora BORDERCOLORCACHE
+	sta BORDERCOLOR	
+	lda TEXTCOLORCACHE
+	sta TEXTCOLOR
 	rts
 
 ioErrorJmp:
 	jmp ioError
 
 
-; This table lives here in the loader because we need to copy
+loaderPalette:
-; it to a specific free hole in bank E1
+	.word $0aef,$06af,$0080,$0861,$0c93,$0eb4,$0d66,$0f9a,$0777,$0f00,$0bbb,$ddd,$007b,$0a5b,$0000,$0fff
-vramRowInvertedSpanLookup:
-	.word $9d00,$9c60,$9bc0,$9b20,$9a80,$99e0,$9940,$98a0,$9800,$9760,$96c0,$9620,$9580,$94e0,$9440,$93a0,$9300,$9260,$91c0,$9120
-	.word $9080,$8fe0,$8f40,$8ea0,$8e00,$8d60,$8cc0,$8c20,$8b80,$8ae0,$8a40,$89a0,$8900,$8860,$87c0,$8720,$8680,$85e0,$8540,$84a0
-	.word $8400,$8360,$82c0,$8220,$8180,$80e0,$8040,$7fa0,$7f00,$7e60,$7dc0,$7d20,$7c80,$7be0,$7b40,$7aa0,$7a00,$7960,$78c0,$7820
-	.word $7780,$76e0,$7640,$75a0,$7500,$7460,$73c0,$7320,$7280,$71e0,$7140,$70a0,$7000,$6f60,$6ec0,$6e20,$6d80,$6ce0,$6c40,$6ba0
-	.word $6b00,$6a60,$69c0,$6920,$6880,$67e0,$6740,$66a0,$6600,$6560,$64c0,$6420,$6380,$62e0,$6240,$61a0,$6100,$6060,$5fc0,$5f20
-	.word $5e80,$5de0,$5d40,$5ca0,$5c00,$5b60,$5ac0,$5a20,$5980,$58e0,$5840,$57a0,$5700,$5660,$55c0,$5520,$5480,$53e0,$5340,$52a0
-	.word $5200,$5160,$50c0,$5020,$4f80,$4ee0,$4e40,$4da0,$4d00,$4c60,$4bc0,$4b20,$4a80,$49e0,$4940,$48a0,$4800,$4760,$46c0,$4620
-	.word $4580,$44e0,$4440,$43a0,$4300,$4260,$41c0,$4120,$4080,$3fe0,$3f40,$3ea0,$3e00,$3d60,$3cc0,$3c20,$3b80,$3ae0,$3a40,$39a0
-	.word $3900,$3860,$37c0,$3720,$3680,$35e0,$3540,$34a0,$3400,$3360,$32c0,$3220,$3180,$30e0,$3040,$2fa0,$2f00,$2e60,$2dc0,$2d20
-	.word $2c80,$2be0,$2b40,$2aa0,$2a00,$2960,$28c0,$2820,$2780,$26e0,$2640,$25a0,$2500,$2460,$23c0,$2320,$2280,$21e0,$2140,$20a0
-vramRowInvertedSpanLookupEnd:
 
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -329,13 +320,6 @@ fileOpenCode:
 	.byte 0					; Result (file handle)
 	.byte 0					; Padding
 
-fileOpenCodeE1:
-	.byte 3
-	.addr codePathE1
-	.addr $9200				; 1k below BASIC.SYSTEM
-	.byte 0					; Result (file handle)
-	.byte 0					; Padding
-
 fileRead:
 	.byte 4
 	.byte 1					; File handle (we know it's gonna be 1)
@@ -371,11 +355,11 @@ fileOpenFonts:
 
 codePath:
 	pstring "/GSAPP/CODEBANK"
-codePathE1:
-	pstring "/GSAPP/CODEBANKE1"
 spritePath:
 	pstring "/GSAPP/SPRITEBANK"
 soundPath:
 	pstring "/GSAPP/SOUNDBANK"
 fontPath:
 	pstring "/GSAPP/FONTBANK"
+
+.include "loaderGraphics.s"

loaderGraphics.s

@@ -0,0 +1,164 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; slowColorFill
+; Fills the screen with a color (or two). Slow because it has to run from
+; bank 0 on the slow graphics path
+;
+; A = 4:4:4:4 = Palette entries to fill
+;
+; Trashes X,Y
+
+slowColorFill:
+	ldy #200
+	ldx #$2000
+	
+slowColorFillLoop:
+	; 80 STAs, for 1 line
+	; sta VRAMBANK,x	inx		inx
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+	.byte $9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8,$9F,$00,$00,$E1,$e8,$e8
+
+	dey
+	beq slowColorFillLoopDone
+	jmp slowColorFillLoop
+
+slowColorFillLoopDone:
+	rts
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; initSCBs
+; Initialize all scanline control bytes
+;
+; Trashes A,X
+
+initSCBs:
+	lda #0
+	ldx #$0100	;set all $100 scbs to A
+
+initSCBsLoop:
+	dex
+	dex
+	sta $e19d00,x
+	bne initSCBsLoop
+	rts
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; setScanlinePalette
+; Set the palette for a given scan line
+;
+; PARAML0 = Palette index
+; X = Start scan line
+; Y = Count
+
+setScanlinePalette:
+	pha
+
+setScanlinePaletteLoop:
+	lda $e19d00,x
+	ora PARAML0
+	sta $e19d00,x
+	inx
+	dey
+	bne setScanlinePaletteLoop
+
+	pla
+	rts
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; setPalette
+; Set all colors in a palette from memory
+; PARAML0 = Pointer to 32 color bytes
+; A = Palette index
+;
+setPalette:
+	SAVE_XY
+
+	asl
+	asl
+	asl
+	asl
+	asl
+	BITS8A
+	sta setPaletteLoop_SMC+1
+	BITS16
+	ldx #0
+	ldy #0
+
+setPaletteLoop:
+	lda (PARAML0),y
+setPaletteLoop_SMC:
+	sta $e19e00,x		; Self-modifying code!
+
+	iny
+	iny
+	inx
+	inx
+	cpx #32
+	bne setPaletteLoop
+
+	RESTORE_XY
+	rts
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; Vertical blank checkers
+;
+
+; The Brutal Deluxe version, taken from LemminGS
+;
+nextVBL:
+	lda #75
+	pha
+nextVBL0:
+	lda $e0c02e
+	and #$7f
+	cmp 1,s
+	blt nextVBL0
+	cmp #100
+	bge nextVBL0
+	pla
+waitVBL:
+	lda $e0c018
+	bpl waitVBL
+	rts
+
+
+; The Apple version, taken from GS Tech Note 039
+;
+syncVBL:
+	;sei
+	BITS8
+syncVBL0:
+	ldaA $C02f
+    asl         ; VA is now in the Carry flag
+	ldaA $C02e
+    rol         ; Roll Carry into bit 0
+	cmp #200	; A now contains line number
+	blt syncVBL0
+	BITS16
+	;cli
+	rts
+
+; The old style //e version
+;
+vblSync:
+	BITS8
+
+waitVBLToFinish:
+	lda $E0C019
+	bmi waitVBLToFinish
+waitVBLToStart:
+	lda $E0C019
+	bpl waitVBLToStart
+
+	BITS16
+	rts

terrain_e1.s

@@ -1,297 +0,0 @@
-;
-;  terrain (in E1 bank)
-;
-;  Fill-mode terrain rendering code snippets
-;  that live in bank E1 for maximum speed.
-;
-;  Created by Quinn Dunki on 7/29/17
-;
-
-.include "equates.s"
-.include "macros.s"
-
-UNRENDERCACHESTACK = $7ff	; Stack downwards from bottom of VRAM. Mirrored from $01 into $E1!
-
-OP16
-
-.org $800
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; renderTerrainSpans:
-;
-;
-renderTerrainSpans:
-	SAVE_AXY
-	SAVE_DBR
-	FASTGRAPHICS
-
-	lda #UNRENDERCACHESTACK	; Prepare unrender cache
-	tcs
-
-	lda #MAXTERRAINHEIGHT-1
-	sec
-	sbc lastCompiledTerrainY
-	beq renderTerrainRowSpansSkip		; All terrain needs compiled rendering
-
-renderTerrainSpansLoop:
-	sta PARAML1
-
-	; Find row data
-	lda PARAML1
-	asl		; Shifts must match SPANROWBYTES
-	asl
-	asl
-	asl
-	asl
-	tay
-	lda terrainSpanData,y
-	sta SCRATCHL			; Track span color
-
-	; Find VRAM row
-	lda PARAML1
-	asl
-	tax
-	lda vramRowInvertedSpanLookup,x
-	tax
-	
-	adc #160
-	sta PARAML0				; Watch for end of VRAM row
-
-	; Find span that intersects left logical edge
-	lda #0
-	clc
-
-renderTerrainRowSpansFindLeftLoop:
-	adc terrainSpanData+2,y
-	cmp leftScreenEdge
-	bpl renderTerrainRowSpansFoundLeft
-	iny
-	iny
-	sta CACHEDATA
-	lda SCRATCHL
-	eor #%110000	; Toggle span color cache
-	sta SCRATCHL
-	lda CACHEDATA
-	bra renderTerrainRowSpansFindLeftLoop
-
-renderTerrainRowSpansFoundLeft:
-	sec
-	sbc leftScreenEdge	; A now holds remainder of leftmost span
-						; and Y points to leftmost span
-
-renderTerrainRowSpansLoop:
-	sta SCRATCHL2
-
-	; Set fill mode byte for this span
-	lda SCRATCHL
-	sta VRAMBANK,x
-
-	; Cache the index we wrote to so we can erase later
-	phx
-
-	; Advance to end of span
-	clc
-	txa
-	adc SCRATCHL2
-	cmp PARAML0
-	bpl renderTerrainRowSpansDone
-	tax
-
-	; Prepare for next span
-	iny
-	iny
-	lda SCRATCHL
-	eor #%110000	; Toggle span color cache
-	sta SCRATCHL
-
-	lda terrainSpanData+2,y
-	bra renderTerrainRowSpansLoop
-
-renderTerrainRowSpansDone:
-	lda PARAML1
-	dec
-	bne renderTerrainSpansLoop
-
-	pea 0		; Null-terminate the unrender cache
-
-renderTerrainRowSpansSkip:
-	SLOWGRAPHICS
-	RESTORE_DBR
-	RESTORE_AXY
-	rtl
-
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; unrenderTerrainSpans:
-;
-;
-
-unrenderTerrainSpans:
-	SAVE_AXY
-	SAVE_DBR
-	phb
-	pea $e1e1		; Work entirely in bank E1 for all local read/writes
-	plb
-	plb
-
-	ldy #UNRENDERCACHESTACK-1
-
-unrenderTerrainSpansLoop:
-	lda 0,y
-	beq unrenderTerrainSpansDone
-	tax
-	lda #0
-	sta a:0,x
-	dey
-	dey
-	bra unrenderTerrainSpansLoop
-
-unrenderTerrainSpansDone:
-	plb
-	RESTORE_DBR
-	RESTORE_AXY
-	rtl
-
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; compileTerrainSpans:
-;
-;
-compileTerrainSpans:
-	pha
-	SAVE_DBR
-	lda #0
-
-compileTerrainSpansLoop:
-	sta PARAML1
-	jsr compileTerrainSpansRow
-	lda PARAML1
-	inc
-	cmp #MAXTERRAINHEIGHT
-	bne compileTerrainSpansLoop
-
-	RESTORE_DBR
-	pla
-	rtl
-
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; compileTerrainSpansRow:
-;
-; PARAML1 = Row index (bottom relative)
-;
-; Trashes SCRATCHL
-;
-compileTerrainSpansRow:
-	SAVE_AXY
-
-	lda PARAML1
-	asl		; Shifts must match SPANROWBYTES
-	asl
-	asl
-	asl
-	asl
-	clc
-	adc #terrainSpanData
-	sta SCRATCHL
-
-	ldy #0
-	ldx #TERRAINWIDTH-2
-
-	lda terrainDataFar,x	; Figure out start value for row
-	cmp PARAML1
-	bcs compileTerrainSpansRowInitGreen
-
-compileTerrainSpansRowInitBlack:
-	lda #$0010		; First span is black
-	sta (SCRATCHL)	; Initialize the row
-	inc SCRATCHL
-	inc SCRATCHL
-	ldy #-1
-
-compileTerrainSpansRowBlackStart:
-	iny
-
-compileTerrainSpansRowBlackLoop:
-	lda terrainDataFar,x
-	cmp PARAML1
-	bcs compileTerrainSpansBlackEnd
-	dex
-	dex
-	iny
-	cpx #-2
-	bne compileTerrainSpansRowBlackLoop
-
-compileTerrainSpansBlackEnd:
-	tya				; Store this span's length
-	sta (SCRATCHL)
-	inc SCRATCHL
-	inc SCRATCHL
-
-	dex				; Begin searching for next span
-	dex
-	cpx #0
-	bmi compileTerrainSpansRowDone
-	ldy #0
-	bra compileTerrainSpansRowGreenStart
-
-compileTerrainSpansRowDone:
-	RESTORE_AXY
-	rts
-
-compileTerrainSpansRowInitGreen:
-	lda #$0020		; First span is green
-	sta (SCRATCHL)	; Initialize the row
-	inc SCRATCHL
-	inc SCRATCHL
-	ldy #-1
-
-compileTerrainSpansRowGreenStart:
-	iny
-
-compileTerrainSpansRowGreenLoop:
-	lda terrainDataFar,x
-	cmp PARAML1
-	bcc compileTerrainSpansGreenEnd
-	dex
-	dex
-	iny
-	cpx #-2
-	bne compileTerrainSpansRowGreenLoop
-
-compileTerrainSpansGreenEnd:
-	tya				; Store this span's length
-	sta (SCRATCHL)
-	inc SCRATCHL
-	inc SCRATCHL
-
-	dex				; Begin searching for next span
-	dex
-	cpx #0
-	bmi compileTerrainSpansRowDone
-	ldy #0
-	bra compileTerrainSpansRowBlackStart
-
-terrainSpanData:
-	.repeat MAXTERRAINHEIGHT
-		.word 0		; Start value (0=BG)
-		.repeat MAXSPANSPERROW
-		.word 0		; Length (in bytes)
-		.endrepeat
-	.endrepeat
-
-
-vramRowInvertedSpanLookup = $16C0	; This table is copied to here by the loader
-
-
-.export renderTerrainSpans
-.export unrenderTerrainSpans
-.export compileTerrainSpans
-
-
-; Suppress some linker warnings - Must be the last thing in the file
-.SEGMENT "ZPSAVE"
-.SEGMENT "EXEHDR"
-.SEGMENT "STARTUP"
-.SEGMENT "INIT"
-.SEGMENT "LOWCODE"