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base:double_screen_horizontal_scroller [2015-04-17 04:31] (current)
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 +==== Horizontal Double Screen Bitmap Scroller ====
 +== Done with VSP ==
 +{{:​base:​vsp.zip|Download}}
 +<​code>​
 +//​---------------------------------------------------------------------------------------------------------------------
 +// Horizontal Double Screen Bitmap Scroller, done with VSP
 +// For the C64pixels.com Double Screen Pixeling Compo
 +// Code: Cruzer/CML, April 2011
 +// Based on a routine from Codebase64 by Martin Piper
 +// Can be used/​modified/​distributed freely
 +// Asm: KickAss 3.15
 +// Tab: 16 chars
 +//​---------------------------------------------------------------------------------------------------------------------
 +// Picture size: 80x25 chars, in either multicolor or hires bitmap.
 +// Gfx can be imported either as two c64 pics or a PNG file.
 +// C64 pics:
 +// - Set importMode = C64_MODE
 +// - Save pics as "​pic0.prg"​ and "​pic1.prg",​ or *.p00
 +// - For multicolor pics use Koala format
 +// - For hires pics use Topaz Hires Editor format (starts with color screen, followed by bitmap at a $400 offset)
 +// - Set c64FileType to "​prg"​ or "​p00"​
 +// PNG:
 +// - Set importMode = PNG_MODE
 +// - Save pic as "​pic.png"​
 +// - Size: 640x201 (only the lower 200 lines are used for gfx)
 +// - The upper line is used for defining the c64 palette, with hires or multicolor sized pixels depending on the mode
 +// - The pixel to the right of the palette defines the background color
 +// For both formats:
 +// - Set multiColorMode = true/false
 +// - Set borderColor manually or leave it as -1 to make it the same as the bg color
 +// - Adjust sineLength for slower/​faster speed
 +//​---------------------------------------------------------------------------------------------------------------------
 +// Code info:
 +// VSP can only push the screen 40 chars, so with extended borders the visible pic could only be 78 chars wide.
 +// To get full double screen size I added an extra displaced bitmap screen for the two last chars.
 +// When switching to/from this, the d800 colors need to be moved, since they can't be bank switched.
 +// This would of course have been easier with linecrunch, but I wasn't in the mood for finding out whether it was
 +// possible while keeping the gfx 25 chars high.
 +//​---------------------------------------------------------------------------------------------------------------------
 +//params...
 +.enum {PNG_MODE, C64_MODE}
 +.const importMode = PNG_MODE
 +.const multiColorMode = true
 +.const c64FileType = "​prg"​
 +.const sineAmp = $150
 +.const sineLength = $cc
 +.var borderColor = -1
 +//​---------------------------------------------------------------------------------------------------------------------
 +//​zeropage...
 +.const pnt0 = $02 //2
 +.const pnt1 = $04 //2
 +.const xPos = $06 //1
 +.const yPos = $07 //1
 +.const xPosChr = $08 //1
 +.const source = $09 //2
 +.const target = $0b //3
 +.const srcPos = $0e //1
 +.const destPos = $0f //1
 +.const destPosBitmap = $10 //2
 +.const dir = $12 //1
 +.const d16 = $13 //1
 +.const dmaDelay = $14 //1
 +//​---------------------------------------------------------------------------------------------------------------------
 +//memory...
 +.const basic = $0801 //080f
 +.const tune = $1000 //1fff
 +.const main = $2000 //3fff
 +.const sineLo = $4400 //47ff
 +.const sineHi = $4800 //4bff
 +.const bitmapLut = $4c00 //8bff
 +.const screen = $8c00 //8fff
 +.const screenLut = $9000 //97ff
 +.const d800Lut = $9800 //9fff
 +.const bitmap = $a000 //bfff
 +.const bitmap2 = $c000 //dfff
 +.const screen2 = $e000 //e3ff
 +//​---------------------------------------------------------------------------------------------------------------------
 +.const unused = $fff6
 +.const border = unused
 +.const irqLine = $2d
 +.const ProcessorPortDDRDefault = %00101111
 +.const ProcessorPortAllRAMWithIO = %00100101
 +.const CIA1InterruptControl = $dc0d
 +.const CIA1TimerAControl = $dc0e
 +.const CIA1TimerBControl = $dc0f
 +.const CIA2InterruptControl = $dd0d
 +.const CIA2TimerAControl = $dd0e
 +.const CIA2TimerBControl = $dd0f
 +.const VIC2InteruptControl = $d01a
 +.const VIC2InteruptStatus = $d019
 +.var bgColor
 +//​---------------------------------------------------------------------------------------------------------------------
 +//general scripts...
  
 +.function _16bit_nextArgument(arg) {
 + .if (arg.getType()==AT_IMMEDIATE) .return CmdArgument(arg.getType(),​ >​arg.getValue())
 + .return CmdArgument(arg.getType(),​arg.getValue()+1)
 +}
 +
 +.pseudocommand mb arg1;arg2 { //move byte
 + lda arg1
 + sta arg2
 +}
 +
 +.pseudocommand mw src;tar { //move word
 + lda src
 + sta tar
 +
 + .if (src.getType() == AT_IZEROPAGEY) {
 + iny
 + lda src
 + } else {
 + lda _16bit_nextArgument(src)
 + }
 +
 + .if (tar.getType() == AT_IZEROPAGEY) {
 + .if (src.getType() != AT_IZEROPAGEY) iny
 + sta tar
 + } else {
 + sta _16bit_nextArgument(tar)
 + }
 +}
 +//​---------------------------------------------------------------------------------------------------------------------
 +//scripting for png import...
 +
 +.function getC64Color(xPos,​ yPos, pic, rgb2c64) {
 + .if (multiColorMode) .eval xPos = xPos*2
 + .var rgb = pic.getPixel(xPos,​ yPos+1)
 + .var c64Color = rgb2c64.get(rgb)
 + .return c64Color
 +}
 +
 +.var charWidth = 8
 +.var numBlockColors = 2
 +.if (multiColorMode) {
 + .eval charWidth = 4
 + .eval numBlockColors = 3
 +}
 +
 +.function getBlockColors(chrX,​ chrY, pic, rgb2c64) {
 + .var colorCounts = List()
 + .for (var i=0; i<16; i++) .eval colorCounts.add(0)
 + .for (var pixY=0; pixY<8; pixY++) {
 + .for (var pixX=0; pixX<​charWidth;​ pixX++) {
 + .var c64Color = getC64Color(chrX*charWidth + pixX, chrY*8 + pixY, pic, rgb2c64)
 + .eval colorCounts.set(c64Color,​ colorCounts.get(c64Color) + 1)
 + }}
 + .if (multiColorMode) .eval colorCounts.set(bgColor,​0)
 + .for (var i=0; i<16; i++) .eval colorCounts.set(i,​ [colorCounts.get(i) << 4] | i)
 + .eval colorCounts.sort()
 + .eval colorCounts.reverse()
 + .var blockColors = List()
 + .for (var i=0; i<16; i++) .eval blockColors.add(0)
 + .for (var i=0; i<​numBlockColors;​ i++) {
 + .var c64Color = colorCounts.get(i) & $0f
 + .eval blockColors.set(c64Color,​ i+1)
 + }
 + .return blockColors
 +}
 +
 +.function getBlock(chrX,​ chrY, pic, rgb2c64) {
 + .var blockColors = getBlockColors(chrX,​ chrY, pic, rgb2c64)
 + .var blockData = List()
 + .for (var pixY=0; pixY<8; pixY++) {
 + .var bitmapByte = 0
 + .for (var pixX=0; pixX<​charWidth;​ pixX++) {
 + .var c64Color = getC64Color(chrX*charWidth + pixX, chrY*8 + pixY, pic, rgb2c64)
 + .var multiColor = blockColors.get(c64Color)
 + .if (multiColorMode) .eval bitmapByte = bitmapByte | [multiColor << [6 - pixX*2]]
 + .if (!multiColorMode) .eval bitmapByte = bitmapByte | [[[multiColor-1]^1] << [7 - pixX]]
 + }
 + .eval blockData.add(bitmapByte)
 + }
 + .for (var multiColor=1;​ multiColor<​4;​ multiColor++) {
 + .var c64Color = 0
 + .for (var i=1; i<16; i++) {
 + .if (blockColors.get(i) == multiColor) .eval c64Color = i
 + }
 + .eval blockData.add(c64Color)
 + }
 + .return blockData
 +}
 +
 +.var bitmapData = List()
 +.var screenData = List()
 +.var d800Data = List()
 +
 +.function parseDoublePic(pic,​ rgb2c64) {
 + .for (var picNo=0; picNo<2; picNo++) {
 + .for (var chrY=0; chrY<25; chrY++) {
 + .for (var chrX=0; chrX<40; chrX++) {
 + .var block = getBlock(chrX+picNo*40,​ chrY, pic, rgb2c64)
 + .for (var i=0; i<8; i++) .eval bitmapData.add(block.get(i))
 + .var scrColor = [block.get(8) << 4] | [block.get(9) & $f]
 + .eval screenData.add(scrColor)
 + .if (multiColorMode) .eval d800Data.add(block.get(10))
 + }}}
 +}
 +
 +.function initPalette(pngPic) {
 + .var rgb2c64 = Hashtable()
 + .for (var i=0; i<16; i++) {
 + .var xPos = i
 + .if (multiColorMode) .eval xPos = i*2
 + .var rgb = pngPic.getPixel(xPos,​0)
 + .eval rgb2c64.put(rgb,​ i)
 + }
 + .var bgRgb = pngPic.getPixel(32,​0)
 + .eval bgColor = rgb2c64.get(bgRgb)
 + .if (borderColor == -1) .eval borderColor = bgColor
 + .return rgb2c64
 +}
 +
 +.if (importMode == PNG_MODE) {
 + .var pngPic = LoadPicture("​pic.png"​)
 + .var rgb2c64 = initPalette(pngPic)
 + .eval parseDoublePic(pngPic,​ rgb2c64)
 +}
 +//​---------------------------------------------------------------------------------------------------------------------
 +//scripting for c64 file import...
 +
 +.const KOALA_PRG = "​Bitmap=$0002,​ Screen=$1f42,​ D800=$232a, BackgroundColor=$2712"​
 +.const KOALA_P00 = "​Bitmap=$001c,​ Screen=$1f5c,​ D800=$2344, BackgroundColor=$272c"​
 +.const HIRES_PRG = "​Screen=$0002,​ Bitmap=$0402"​
 +.const HIRES_P00 = "​Screen=$001c,​ Bitmap=$041c"​
 +.var c64Pics = List()
 +.if (importMode == C64_MODE) {
 + .if (multiColorMode && c64FileType == "​prg"​) {
 + .eval c64Pics.add(LoadBinary("​pic0.prg",​ KOALA_PRG))
 + .eval c64Pics.add(LoadBinary("​pic1.prg",​ KOALA_PRG))
 + }
 + .if (multiColorMode && c64FileType == "​p00"​) {
 + .eval c64Pics.add(LoadBinary("​pic0.p00",​ KOALA_P00))
 + .eval c64Pics.add(LoadBinary("​pic1.p00",​ KOALA_P00))
 + }
 + .if (!multiColorMode && c64FileType == "​prg"​) {
 + .eval c64Pics.add(LoadBinary("​pic0.prg",​ HIRES_PRG))
 + .eval c64Pics.add(LoadBinary("​pic1.prg",​ HIRES_PRG))
 + }
 + .if (!multiColorMode && c64FileType == "​p00"​) {
 + .eval c64Pics.add(LoadBinary("​pic0.p00",​ HIRES_P00))
 + .eval c64Pics.add(LoadBinary("​pic1.p00",​ HIRES_P00))
 + }
 + .if (multiColorMode) .eval bgColor = c64Pics.get(0).getBackgroundColor()
 + .if (!multiColorMode) .eval bgColor = 0
 + .if (borderColor == -1) .eval borderColor = bgColor
 +}
 +//​---------------------------------------------------------------------------------------------------------------------
 +//generate look-up tables with bitmap data...
 +
 +.pc = bitmapLut "​bitmapLut"​
 +.for (var yPos=0; yPos<​200;​ yPos++) {
 + .for (var pic=0; pic<2; pic++) {
 + .for (var xPos=0; xPos<40; xPos++) {
 + .if (importMode == C64_MODE) {
 + .by c64Pics.get(pic).getBitmap([yPos>>​3]*$140 + [yPos&​7] + xPos*8)
 + }
 + .if (importMode == PNG_MODE) {
 + .by bitmapData.get([yPos>>​3]*$140 + [yPos&​7] + xPos*8 + pic*8000)
 + }
 + }
 + }
 +}
 +
 +.pc = screenLut "​screenLut"​
 +.for (var yPos=0; yPos<25; yPos++) {
 + .for (var pic=0; pic<2; pic++) {
 + .for (var xPos=0; xPos<40; xPos++) {
 + .if (importMode == C64_MODE) {
 + .by c64Pics.get(pic).getScreen(yPos*40 + xPos)
 + }
 + .if (importMode == PNG_MODE) {
 + .by screenData.get(yPos*40 + xPos + pic*1000)
 + }
 + }
 + }
 +}
 +
 +.if (multiColorMode) {
 +.pc = d800Lut "​d800Lut"​
 +.for (var yPos=0; yPos<25; yPos++) {
 + .for (var pic=0; pic<2; pic++) {
 + .for (var xPos=0; xPos<40; xPos++) {
 + .if (importMode == C64_MODE) {
 + .by c64Pics.get(pic).getD800(yPos*40 + xPos)
 + }
 + .if (importMode == PNG_MODE) {
 + .by d800Data.get(yPos*40 + xPos + pic*1000)
 + }
 + }
 + }
 +}
 +}
 +//​---------------------------------------------------------------------------------------------------------------------
 +.pc = basic "​basic"​
 +:​BasicUpstart(main)
 +
 +.var sineValues = List()
 +.for (var i=0; i<​sineLength;​ i++) {
 + .var val = sineAmp/2 * sin(i/​[sineLength/​2/​PI])
 + .eval val = sineAmp/2 + val * 0.999999999
 + .eval sineValues.add(floor(val))
 +}
 +
 +.pc = sineLo "​sineLo"​
 + .var d016mc = $00
 + .if (multiColorMode) .eval d016mc = $10
 + .fill sineLength, [sineValues.get(i) & 7] | d016mc
 +
 +.pc = sineHi "​sineHi"​
 + .fill sineLength, sineValues.get(i) >> 3
 +//​---------------------------------------------------------------------------------------------------------------------
 +.pc = main "​main"​
 + sei
 + cld
 + ldx #$ff
 + txs
 + jsr init
 + cli
 +//​---------------------------------------------------------------------------------------------------------------------
 +{
 +mainLoop:
 +!: lda topIRQDone
 + beq !-
 + :mb #0; topIRQDone
 +
 + lda $d011
 + bpl *-3
 + inc border
 +
 + jsr setScrollParams
 + .if (multiColorMode) jsr updateD800
 + jsr updateBitmap
 + jsr incCnt
 +
 + :mb #0; border
 + jmp mainLoop
 +}
 +//​---------------------------------------------------------------------------------------------------------------------
 +.align $100
 +topIrq:
 + //​stabilize raster with double irq
 +
 + //@ line 45
 + pha
 + txa
 + pha
 + tya
 + pha
 +
 + inc topIRQDone
 +
 + :mw #irq2; $fffe
 + inc $d012
 +
 + :mb #1; VIC2InteruptStatus //​ack raster interupt
 +
 + tsx
 + cli
 + //these nops never really finish due to the raster IRQ triggering again
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 +//​---------------------------------------------------------------------------------------------------------------------
 +irq2:
 + //@ line 46
 + txs
 +
 + ldx #9
 +!: dex
 + bne !-
 +
 + //final cycle wobble check
 + lda #irqLine+1
 + cmp $d012
 + beq *+2
 +
 + //the raster is now stable! \o/
 +
 + //@ line 47
 + :mb #$31; $d011
 +
 + //waste more cycles
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 +
 + //still @ line 47
 +
 + lda dmaDelay
 + lsr //divide by 2 to get the number of nops to skip
 + sta branch+1
 + clv //force branch always
 +
 + //@ line 48
 +
 + bcc branch //1 cycle extra delay depending on the least significant bit of the x offset
 +branch: bvc * //branch somewhere into the nops depending on the x offset position
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 + nop
 +
 + //show raster position
 + inc border
 + dec border
 +
 + //do the VSP by tweaking d011 at the correct time
 + lda #$3b
 + dec $d011
 + inc $d011
 + sta $d011
 +
 + ldx extraScreenOn
 + :mb d018s,x; $d018
 + :mb dd00s,x; $dd00
 + :mb d16; $d016
 +
 + //restart the IRQ chain
 + :mw #topIrq; $fffe
 + :mb #irqLine; $d012
 + :mb #1; VIC2InteruptStatus //​ack raster interupt
 +
 + pla
 + tay
 + pla
 + tax
 + pla
 +interruptReturn:​
 + rti
 +
 +d018s: .by $38,$80
 +dd00s: .by $95,$94
 +extraScreenOn:​ .by 1,1
 +topIRQDone:​ .by 0
 +//​---------------------------------------------------------------------------------------------------------------------
 +incCnt:
 + inc cnt+0
 + bne !+
 + inc cnt+1
 +!: lda cnt+0
 + cmp #<​sineLength
 + bne !+
 + lda cnt+1
 + cmp #>​sineLength
 + bne !+
 + :mw #0; cnt
 +!: rts
 +
 +cnt: .wo sineLength/​4 ​ //start to the left
 +//​---------------------------------------------------------------------------------------------------------------------
 +setScrollParams:​
 + :mb #0; pnt0+0
 + lda cnt+1
 + clc
 + adc #>sineLo
 + sta pnt0+1
 +
 + ldy cnt+0
 + :mb (pnt0),y; d16
 +
 + lda cnt+1
 + clc
 + adc #>sineHi
 + sta pnt0+1
 +
 + ldx #0
 + lda (pnt0),y
 + cmp xPosChr
 + beq !+
 + ldx #1
 + cmp xPosChr
 + bpl !+
 + ldx #-1
 +!: sta xPosChr
 + stx dir
 +
 + ldy #0
 + lda #39
 + sec
 + sbc xPosChr
 + bcs !+
 + adc #40
 + iny
 +!: sta dmaDelay
 + sty extraScreenOn
 +
 + rts
 +//​---------------------------------------------------------------------------------------------------------------------
 +updateD800:
 +.if (multiColorMode) {
 + ldy extraScreenOn
 + cpy extraScreenOn+1
 + beq !+
 + cpy #1
 + beq extra
 + jsr moveD800Normal
 + jmp !+
 +extra: jsr moveD800Extra
 +!:
 + :mb extraScreenOn;​ extraScreenOn+1
 + rts
 +}
 +//​---------------------------------------------------------------------------------------------------------------------
 +updateBitmap:​
 +{
 + lda dir
 + bne !+
 + //no char-pos change
 + rts
 +!:
 + lda extraScreenOn
 + beq !+
 + //no bitmap update needed for extra screen
 + rts
 +!:
 + lda xPosChr
 + ldx dir
 + bmi !+
 + clc
 + adc #39
 +!: sta srcPos
 +
 + lda #81
 + sec
 + sbc srcPos
 + sta srcPos
 + tax
 +
 + lda #40
 + ldy dir
 + bpl !+
 + lda #79
 +!: sec
 + sbc xPosChr
 + sta destPos
 + tay
 +
 +.for (var i=0; i<24; i++) {
 + lda screenLut-1 + i*80,x
 + sta screen + i*40,y
 + lda d800Lut-1 + i*80,x
 + sta $d800 + i*40,y
 +}
 +
 + //special case for lowest line, which needs to wrap to top of screen when it scrolls far enough
 + cpy #64
 + bpl wrap
 +normal:
 + lda screenLut-1 + 24*80,x
 + sta screen + 24*40,y
 + lda d800Lut-1 + 24*80,x
 + sta $d800 + 24*40,y
 + jmp done
 +wrap:
 + lda screenLut-1 + 24*80,x
 + sta screen-$400 + 24*40,y
 + lda d800Lut-1 + 24*80,x
 + sta $d800-$400 + 24*40,y
 +done:
 +
 + :mb destPos; destPosBitmap+0
 + lda #0
 + asl destPosBitmap+0
 + rol
 + asl destPosBitmap+0
 + rol
 + asl destPosBitmap+0
 + rol
 + sta destPosBitmap+1
 +
 + ldy destPosBitmap+0
 + lda destPosBitmap+1
 + bne !+
 + jmp storeBitmap0
 +!: cmp #1
 + bne !+
 + jmp storeBitmap1
 +!: jmp storeBitmap2
 +}
 +//​---------------------------------------------------------------------------------------------------------------------
 +.macro storeBitmap(offset) {
 + .for (var i=0; i<200; i++) {
 + lda bitmapLut - 1 + i*80,x
 + .var target = bitmap + offset + [i&7] + [[i>>​3]*$140]
 + .if (offset == $200 && i >= 192) .eval target = target - $2000 //wrapping
 + sta target,y
 + }
 + rts
 +}
 +storeBitmap0:​ :​storeBitmap($000)
 +storeBitmap1:​ :​storeBitmap($100)
 +storeBitmap2:​ :​storeBitmap($200)
 +//​---------------------------------------------------------------------------------------------------------------------
 +//move d800 data when switching between normal/​special bitmap screen...
 +.macro moveD800(srcOffset,​ tarOffset) {
 + .for (var yPos=0; yPos<25; yPos++) {
 + .if (yPos < 24) {
 + ldx #9
 + !:
 + .for (var xPos=0; xPos<40; xPos=xPos+10) {
 + lda d800Lut + xPos + yPos*80 + srcOffset,x
 + sta $d800 + [[xPos + yPos*40 + tarOffset] & $3ff],x
 + }
 + dex
 + bpl !-
 + } else {
 + //avoid loops for lowest line to make it wrappable...
 + .for (var xPos=0; xPos<40; xPos++) {
 + lda d800Lut + xPos + yPos*80 + srcOffset
 + sta $d800 + [[xPos + yPos*40 + tarOffset] & $3ff]
 + }
 + }
 + }
 + rts
 +}
 +moveD800Normal:​ .if (multiColorMode) :​moveD800($02,​$01)
 +moveD800Extra:​ .if (multiColorMode) :​moveD800($00,​$27)
 +//​---------------------------------------------------------------------------------------------------------------------
 +init:
 + :mb #$0b; $d011
 + :mb #$00; $d015
 + :mb #​borderColor;​ $d020
 + :mb #bgColor; $d021
 +
 + jsr clearInterrupts
 + jsr initGfx
 + jsr setScrollParams
 + jsr initInterrupts
 +
 + rts
 +//​---------------------------------------------------------------------------------------------------------------------
 +clearInterrupts:​
 + :mb #​ProcessorPortDDRDefault;​ $00
 + :mb #​ProcessorPortAllRAMWithIO;​ $01
 + // Clear all CIA to known state, interrupts off.
 + lda #$7f
 + sta CIA1InterruptControl
 + sta CIA2InterruptControl
 + lda #0
 + sta VIC2InteruptControl
 + sta CIA1TimerAControl
 + sta CIA1TimerBControl
 + sta CIA2TimerAControl
 + sta CIA2TimerBControl
 +
 + // Ack any interrupts that might have happened from the CIAs
 + lda CIA1InterruptControl
 + lda CIA2InterruptControl
 + // Ack any interrupts that have happened from the VIC2
 + :mb #$ff; VIC2InteruptStatus
 +
 + // Setup kernal and user mode IRQ vectors to point to a blank routine
 + :mw #​interruptReturn;​ $fffe
 + :mw #​interruptReturn;​ $fffa
 +
 + rts
 +//​---------------------------------------------------------------------------------------------------------------------
 +initInterrupts:​
 + // Setup raster IRQ
 + :mw #topIrq; $fffe
 + :mb #1; VIC2InteruptControl
 + :mb #irqLine; $d012
 + :mb #$3b; $d011
 +
 + // Ack any interrupts that might have happened from the CIAs
 + lda CIA1InterruptControl
 + lda CIA2InterruptControl
 + // Ack any interrupts that have happened from the VIC2
 + :mb #$ff; VIC2InteruptStatus
 +
 + rts
 +//​---------------------------------------------------------------------------------------------------------------------
 +initGfx:
 + //init bitmap screens, color screens and d800
 +
 + :mw #​bitmapLut+2;​ source
 + :mw #$08; target
 + :mb #>​bitmap;​ target+2
 + jsr initBitmap
 +
 + :mw #​screenLut+2;​ source
 + :mw #$01; target
 + :mb #>​screen;​ target+2
 + jsr initScreen
 +
 + .if (multiColorMode) jsr moveD800Extra
 +
 + :mb #$34; $01
 +
 + :mw #bitmapLut; source
 + :mw #$138; target
 + :mb #>​bitmap2;​ target+2
 + jsr initBitmap
 +
 + :mw #screenLut; source
 + :mw #$27; target
 + :mb #>​screen2;​ target+2
 + jsr initScreen
 +
 + :mb #$35; $01
 +
 + rts
 +//​---------------------------------------------------------------------------------------------------------------------
 +initBitmap:
 +{
 + :mb #0; yPos
 +yLoop:
 + :mw source; pnt0
 +
 + :mb target+0; pnt1+0
 + lda target+1
 + ora target+2
 + sta pnt1+1
 +
 + :mb #0; xPos
 +xLoop:
 + ldy #0
 + :mb (pnt0),y; (pnt1),y
 +
 + inc pnt0+0
 + bne !+
 + inc pnt0+1
 +!:
 + lda #8
 + clc
 + adc pnt1+0
 + sta pnt1+0
 + lda pnt1+1
 + adc #$00
 + and #$1f
 + ora target+2
 + sta pnt1+1
 +
 + inc xPos
 + lda xPos
 + cmp #40
 + bne xLoop
 +
 + lda #80
 + clc
 + adc source+0
 + sta source+0
 + bcc !+
 + inc source+1
 +!:
 + lda #1
 + clc
 + adc target+0
 + sta target+0
 + bcc !+
 + inc target+1
 +!:
 + lda yPos
 + and #$07
 + cmp #$07
 + bne !+
 +
 + lda #<$138
 + clc
 + adc target+0
 + sta target+0
 + lda #>$138
 + adc target+1
 + and #$1f
 + sta target+1
 +!:
 + inc yPos
 + lda yPos
 + cmp #200
 + beq !+
 + jmp yLoop
 +!:
 + rts
 +}
 +//​---------------------------------------------------------------------------------------------------------------------
 +initScreen:
 +{
 + :mb #0; yPos
 +yLoop:
 + :mw source; pnt0
 +
 + :mb target+0; pnt1+0
 + lda target+1
 + ora target+2
 + sta pnt1+1
 +
 + :mb #0; xPos
 +xLoop:
 + ldy #0
 + :mb (pnt0),y; (pnt1),y
 +
 + inc pnt0+0
 + bne !+
 + inc pnt0+1
 +!:
 + lda #1
 + clc
 + adc pnt1+0
 + sta pnt1+0
 + lda pnt1+1
 + adc #$00
 + and #$03
 + ora target+2
 + sta pnt1+1
 +
 + inc xPos
 + lda xPos
 + cmp #40
 + bne xLoop
 +
 + lda #80
 + clc
 + adc source+0
 + sta source+0
 + bcc !+
 + inc source+1
 +!:
 + lda #40
 + clc
 + adc target+0
 + sta target+0
 + bcc !+
 + inc target+1
 +!:
 + inc yPos
 + lda yPos
 + cmp #25
 + beq !+
 + jmp yLoop
 +!:
 + rts
 +}
 +//​---------------------------------------------------------------------------------------------------------------------
 +</​code>​
base/double_screen_horizontal_scroller.txt ยท Last modified: 2015-04-17 04:31 (external edit)