mirror of
https://github.com/lscharen/iigs-game-engine.git
synced 2024-11-25 00:30:48 +00:00
WIP of BG1 scanline effects
A static BG1 is stable with BG0 offset values. A seam in BG1 needs to be closed up by taking into account the BG1XOrigin value when setting the :shift_value. Also, several routines were hard-coded for the scanline case. These hanges need to be reverted and properly parametereized.
This commit is contained in:
Lucas Scharenbroich
parent
5cfefc350c
commit
9021ee4506
@ -41,6 +41,7 @@ appTmp0 equ 28
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seg1x equ 30
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seg2x equ 32
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seg3x equ 34
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seg4x equ 36 ; BG1 x-pos
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phk
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plb
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@ -51,9 +52,15 @@ seg3x equ 34
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_MTStartUp ; GTE requires the miscellaneous toolset to be running
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lda #ENGINE_MODE_USER_TOOL ; Engine in Fast Mode as a User Tool
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lda #ENGINE_MODE_USER_TOOL+ENGINE_MODE_TWO_LAYER ; Engine in Fast Mode as a User Tool
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jsr GTEStartUp ; Load and install the GTE User Tool
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; Initialize the graphics screen playfield
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pea #160
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pea #200
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_GTESetScreenMode
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; Load a tileset
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pea 0
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@ -67,6 +74,9 @@ seg3x equ 34
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pea #TileSetPalette
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_GTESetPalette
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pea $0
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_GTEClearBG1Buffer
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; Set up our level data
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; jsr BG0SetUp
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@ -76,7 +86,13 @@ seg3x equ 34
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pea App_TileMapBG0+{10*416}
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_GTESetBG0TileMapInfo
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stz seg1x
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stz seg2x
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stz seg3x
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stz seg4x
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jsr SetLimits
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jsr DoLoadBG1
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; Initialize local variables
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@ -315,6 +331,14 @@ IncRanges
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bcc *+5
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lda #0
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sta seg3x
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bit #1
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bne :out
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lda seg4x
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inc
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cmp #160
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bcc *+5
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lda #0
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sta seg4x
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:out
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rts
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@ -348,7 +372,13 @@ SetOffsets
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lda seg2x
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jsr SetOffset2
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lda seg3x
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jmp SetOffset3
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jsr SetOffset3
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pei seg4x
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pea 0
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_GTESetBG1Origin
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rts
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SetOffset1
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ldx #120
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@ -408,6 +438,24 @@ _InitRange
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:done
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rts
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; Load a binary file in the BG1 buffer
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DoLoadBG1
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jsr AllocBank ; Alloc 64KB for Load/Unpack
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sta BankLoad ; Store "Bank Pointer"
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ldx #BG1DataFile ; Load the background file into the bank
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jsr LoadFile
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pea #164 ; Fill everything
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pea #200
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pea #256
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lda BankLoad
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pha
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pea $0000
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pea $0000 ; default flags
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_GTECopyPicToBG1
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rts
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BG1DataFile strl '1/bg1.bin'
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BG0Offsets ds 416
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PUT ../StartUp.s
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11
src/Render.s
11
src/Render.s
@ -156,8 +156,16 @@ _DoOverlay
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; Use the per-scanline tables to set the screen. This is really meant to be used without the built-in tilemap
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; support and is more of a low-level way to control the background rendering
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_RenderScanlines
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lda BG1YTable ; Make sure we're in the right mode
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cmp #$00A0
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beq :ytbl_ok
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lda #1
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jsr _ResetBG1YTable
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lda BG1YTable
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:ytbl_ok
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jsr _ApplyBG0YPos ; Set stack addresses for the virtual lines to the physical screen
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jsr _ApplyBG1YPos ; Set the y-register values of the blitter
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jsr _ApplyScanlineBG1YPos ; Set the y-register values of the blitter
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; _ApplyBG0Xpos need to be split because we have to set the offsets, then draw in any updated tiles, and
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; finally patch out the code field. Right now, the BRA operand is getting overwritten by tile data.
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@ -170,6 +178,7 @@ _RenderScanlines
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; jsr _ApplyTiles ; This function actually draws the new tiles into the code field
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jsr _ApplyScanlineBG0XPos ; Patch the code field instructions with exit BRA opcode
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jsr _ApplyScanlineBG1XPos
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jsr _BuildShadowList ; Create the rages based on the sorted sprite y-values
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@ -500,6 +500,7 @@ _TSCopyPicToBG1
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:src_width equ tmp6
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:src_height equ tmp7
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:src_stride equ tmp8
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:src_flags equ tmp9
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lda :width,s
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sta :src_width
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@ -509,7 +510,8 @@ _TSCopyPicToBG1
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sta :src_stride
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ldy BG1DataBank ; Pick the target data bank
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; lda :flags,s
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lda :flags,s
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sta :src_flags
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; bit #$0001
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; beq *+4
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; ldy BG1AltBank
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@ -12,6 +12,7 @@ _InitBG1
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_CopyBinToBG1
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:src_width equ tmp6
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:src_height equ tmp7
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:src_flags equ tmp9
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clc
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adc #8 ; Advance over the header
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@ -21,10 +22,46 @@ _CopyBinToBG1
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sta :src_width
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lda #208
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sta :src_height
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stz :src_flags
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pla
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jmp _CopyToBG1
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; Reset the BG1 Y-table depending on the rendering mode
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;
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; A = mode
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; 0 = default (base = $1800, stride = 256)
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; 1 = scanline (base = $A0, stride = 324)
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_ResetBG1YTable
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:base equ tmp0
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:stride equ tmp1
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cmp #1 ; scanline mode?
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bne :default
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lda #$A0
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sta :base
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lda #324
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sta :stride
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bra :begin
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:default
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lda #$1800
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sta :base
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lda #256
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sta :stride
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:begin
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ldx #0
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lda :base
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:loop
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sta BG1YTable,x
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sta BG1YTable+{208*2},x
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clc
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adc :stride
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inx
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inx
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cpx #{208*2}
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bcc :loop
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rts
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; Copy a IIgs $C1 picture into BG1. Assumes the file is the correct size (320 x 200)
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;
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@ -35,6 +72,7 @@ _CopyPicToBG1
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:src_width equ tmp6
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:src_height equ tmp7
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:src_stride equ tmp8
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:src_flags equ tmp9
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pha
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lda #160
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@ -43,6 +81,7 @@ _CopyPicToBG1
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lda #200
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sta :src_height
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pla
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stz :src_flags
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jmp _CopyToBG1
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; Generic routine to copy image data into BG1
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@ -54,39 +93,52 @@ _CopyToBG1
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:src_width equ tmp6
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:src_height equ tmp7
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:src_stride equ tmp8
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:src_flags equ tmp9
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:dstptr2 equ tmp10
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sta :srcptr
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stx :srcptr+2
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sty :dstptr+2 ; Everything goes into this bank
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sty :dstptr2+2
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lda #$00A0
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sta :dstptr
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clc
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adc #164 ; leave a 4-byte gap in the middle
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sta :dstptr2
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; "Normal" BG1 mode as a stride of 164 bytes and mirrors the BG0 size (328 x 208)
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; In "Scanline" mode, the BG1 is treated as a 320x200 bitfield with each horizontal line doubled
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lda :src_width
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min #160
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sta :src_width
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lda :src_height
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min #200
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sta :src_height
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stz :line_cnt
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:rloop
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lda :line_cnt ; get the pointer to the code field line
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asl
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tax
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lda BG1YTable,x
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sta :dstptr
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ldy #0 ; move forward in the image data and image data
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:cloop
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lda [:srcptr],y
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sta [:dstptr],y
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sta [:dstptr2],y
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:skip
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iny
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iny
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cpy :src_width
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bcc :cloop
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ldy #164
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lda [:srcptr] ; Duplicate the last couple of words in the extra space at the end of the line
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sta [:dstptr],y
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ldy #2
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lda [:srcptr],y
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ldy #166
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sta [:dstptr],y
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lda :dstptr
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clc
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adc #324
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sta :dstptr
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adc #164
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sta :dstptr2
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lda :srcptr
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clc
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@ -140,6 +192,34 @@ _ApplyBG1XPosPre
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sta BG1StartXMod164
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rts
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; Save as _ApplyBG1XPos, but we pretend that StartXMod164 is always zero and deal with the per-line offset adjustment in
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; _ApplyScanlineBG1YPos. The tweak here is that the buffer is only 160 bytes wide in scanine mode, instead of 164 bytes wide
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_ApplyScanlineBG1XPos
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lda BG1StartXMod164 ; How far into the BG1 buffer is the left edge?
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tay
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phd ; save the direct page because we are going to switch to the
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lda BlitterDP ; blitter direct page space and fill in the addresses
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tcd
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ldx #0
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tya
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:loop
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sta 00,x ; store the value
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inc
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inc
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cmp #164
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bcc *+5
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sbc #164
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inx
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inx
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cpx #164
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bcc :loop
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pld
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rts
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_ApplyBG1XPos
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lda #162
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sec
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@ -196,6 +276,155 @@ _ClearBG1Buffer
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plb
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rts
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; Variation to take care of horizontal adjustments within the BG1 buffer to compensate for the
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; per-scanline BG0 displacement. It is up to the caller to manage the memeory layout to make
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; this visually work.
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;
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; In the scanline mode we have to be able to adjust the base address of each BG1 line up to
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; a full screen, so scanline mode treats bank as a 640x200 pixel bitmap (64000 byte).
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;
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; This is just a limitation of scanline displacement mode that there is no extra vertical space.
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_ApplyScanlineBG1YPos
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:stk_save equ tmp0
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:virt_line_x2 equ tmp1
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:lines_left_x2 equ tmp2
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:draw_count_x2 equ tmp3
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:ytbl_idx_x2 equ tmp4
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:shift_value equ tmp5
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; Avoid local var collision
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:ytbl_idx_pos_x2 equ tmp10
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:virt_line_pos_x2 equ tmp11
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:total_left_x2 equ tmp12
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:current_count_x2 equ tmp13
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:ptr equ tmp14
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lda StartXMod164Tbl
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sta :ptr
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lda StartXMod164Tbl+2
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sta :ptr+2
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ora :ptr
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lda BG1StartY
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jsr Mod208
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sta BG1StartYMod208
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asl
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sta :ytbl_idx_pos_x2 ; Start copying from the first entry in the table
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lda StartYMod208 ; This is the base line of the virtual screen
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asl
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sta :virt_line_pos_x2
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tay
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lda ScreenHeight
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asl
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sta :total_left_x2
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:loop0
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lda [:ptr],y
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tax
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and #$FF00 ; Determine how many sequential lines have this mod value
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xba
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inc
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asl
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min :total_left_x2 ; Don't draw more than the number of lines that are left to process
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sta :current_count_x2 ; Save a copy for later
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sta :lines_left_x2 ; Set the parameter
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lda :ytbl_idx_pos_x2 ; Set the parameter
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sta :ytbl_idx_x2
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sty :virt_line_x2 ; Set the parameter
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txa ; Put the X mod 164 value in the offset value
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and #$00FF
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sta :shift_value
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jsr :_ApplyConstBG1YPos ; Shift this range by a constant amount
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clc
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lda :virt_line_pos_x2
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adc :current_count_x2
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cmp #208*2 ; Do the modulo check in this loop
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bcc *+5
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sbc #208*2
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sta :virt_line_pos_x2
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tay
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clc
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lda :ytbl_idx_pos_x2
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adc :current_count_x2
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sta :ytbl_idx_pos_x2
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lda :total_left_x2
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sec
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sbc :current_count_x2
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sta :total_left_x2
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bne :loop0
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rts
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:_ApplyConstBG1YPos
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lda #164
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sec
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sbc :shift_value
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; bpl *+6
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; clc
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; adc #160
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; clc
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; adc :shift_value
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sta :shift_value
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; cmp #160
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; beq *+4
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; brk $55
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phb ; Save the existing bank
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tsc
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sta :stk_save
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:loop
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ldx :virt_line_x2
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ldal BTableHigh,x ; Get the bank
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pha
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plb
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ldal BTableLow,x ; Get the address of the first code field line
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tay
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txa ; Calculate number of lines to draw on this iteration
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and #$001E
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eor #$FFFF
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sec
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adc #32
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min :lines_left_x2
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sta :draw_count_x2
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tax
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lda :ytbl_idx_x2 ; Read from this location in the BG1YTable
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clc
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CopyBG1YTableToBG1Addr3 :shift_value
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; jsr CopyBG1YTableToBG1Addr
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lda :virt_line_x2 ; advance to the virtual line after
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adc :draw_count_x2 ; filled in
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sta :virt_line_x2
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lda :ytbl_idx_x2
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adc :draw_count_x2
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sta :ytbl_idx_x2
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lda :lines_left_x2 ; subtract the number of lines we just completed
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sec
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sbc :draw_count_x2
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sta :lines_left_x2
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jne :loop
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lda :stk_save
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tcs
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plb
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rts
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; Everytime either BG1 or BG0 Y-position changes, we have to update the Y-register
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; value in all of the code fields (within the visible screen)
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_ApplyBG1YPos
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@ -353,8 +582,103 @@ CopyBG1YTableToBG1Addr
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sta: BG1_ADDR+$0000,y
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:none rts
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; Unrolled copy routine to move BG1YTable entries into BG1_ADDR position
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; with a constant shift applied
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;
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; A = index into the BG1YTable array (x2)
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; Y = starting line * $1000
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; X = number of lines (x2)
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; ]1 = offset
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CopyBG1YTableToBG1Addr3 mac
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jmp (tbl,x)
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tbl da none
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da do01,do02,do03,do04
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da do05,do06,do07,do08
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da do09,do10,do11,do12
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da do13,do14,do15,do16
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do15 tax
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jmp x15
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do14 tax
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jmp x14
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do13 tax
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jmp x13
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do12 tax
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jmp x12
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do11 tax
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jmp x11
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do10 tax
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jmp x10
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do09 tax
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jmp x09
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do08 tax
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jmp x08
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do07 tax
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jmp x07
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do06 tax
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jmp x06
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do05 tax
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jmp x05
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do04 tax
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jmp x04
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do03 tax
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jmp x03
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do02 tax
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jmp x02
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do01 tax
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jmp x01
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do16 tax
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ldal BG1YTable+30,x
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adc ]1
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sta BG1_ADDR+$F000,y
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x15 ldal BG1YTable+28,x
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adc ]1
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sta BG1_ADDR+$E000,y
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x14 ldal BG1YTable+26,x
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adc ]1
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sta BG1_ADDR+$D000,y
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||||
x13 ldal BG1YTable+24,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$C000,y
|
||||
x12 ldal BG1YTable+22,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$B000,y
|
||||
x11 ldal BG1YTable+20,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$A000,y
|
||||
x10 ldal BG1YTable+18,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$9000,y
|
||||
x09 ldal BG1YTable+16,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$8000,y
|
||||
x08 ldal BG1YTable+14,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$7000,y
|
||||
x07 ldal BG1YTable+12,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$6000,y
|
||||
x06 ldal BG1YTable+10,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$5000,y
|
||||
x05 ldal BG1YTable+08,x
|
||||
adc ]1
|
||||
sta: BG1_ADDR+$4000,y
|
||||
x04 ldal BG1YTable+06,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$3000,y
|
||||
x03 ldal BG1YTable+04,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$2000,y
|
||||
x02 ldal BG1YTable+02,x
|
||||
adc ]1
|
||||
sta BG1_ADDR+$1000,y
|
||||
x01 ldal BG1YTable+00,x
|
||||
adc ]1
|
||||
sta: BG1_ADDR+$0000,y
|
||||
none <<<
|
||||
|
||||
; Unrolled copy routine to move BG1YTable entries into BG1_ADDR position with an additional
|
||||
; shift. This has to be split into two
|
||||
; shifton every line. This has to be split into two
|
||||
;
|
||||
; A = index into the BG1YTable array (x2)
|
||||
; Y = starting line * $1000
|
||||
|
||||
Loading…
Reference in New Issue
Block a user