mirror of
https://github.com/blondie7575/GSCats.git
synced 2024-11-22 06:31:48 +00:00
f599267718
I thought it was working after the merging with fill mode, but it actually wasn’t. Should be now. Using only compiled rendering as of this commit.
298 lines
4.9 KiB
ArmAsm
298 lines
4.9 KiB
ArmAsm
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; terrain (in E1 bank)
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;
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; Fill-mode terrain rendering code snippets
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; that live in bank E1 for maximum speed.
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;
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; Created by Quinn Dunki on 7/29/17
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;
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.include "equates.s"
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.include "macros.s"
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UNRENDERCACHESTACK = $7ff ; Stack downwards from bottom of VRAM. Mirrored from $01 into $E1!
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OP16
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.org $800
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; renderTerrainSpans:
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;
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;
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renderTerrainSpans:
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SAVE_AXY
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SAVE_DBR
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FASTGRAPHICS
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lda #UNRENDERCACHESTACK ; Prepare unrender cache
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tcs
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lda #MAXTERRAINHEIGHT-1
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sec
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sbc lastCompiledTerrainY
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beq renderTerrainRowSpansSkip ; All terrain needs compiled rendering
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renderTerrainSpansLoop:
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sta PARAML1
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; Find row data
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lda PARAML1
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asl ; Shifts must match SPANROWBYTES
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asl
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asl
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asl
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asl
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tay
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lda terrainSpanData,y
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sta SCRATCHL ; Track span color
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; Find VRAM row
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lda PARAML1
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asl
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tax
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lda vramRowInvertedSpanLookup,x
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tax
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adc #160
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sta PARAML0 ; Watch for end of VRAM row
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; Find span that intersects left logical edge
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lda #0
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clc
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renderTerrainRowSpansFindLeftLoop:
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adc terrainSpanData+2,y
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cmp leftScreenEdge
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bpl renderTerrainRowSpansFoundLeft
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iny
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iny
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sta CACHEDATA
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lda SCRATCHL
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eor #%110000 ; Toggle span color cache
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sta SCRATCHL
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lda CACHEDATA
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bra renderTerrainRowSpansFindLeftLoop
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renderTerrainRowSpansFoundLeft:
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sec
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sbc leftScreenEdge ; A now holds remainder of leftmost span
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; and Y points to leftmost span
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renderTerrainRowSpansLoop:
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sta SCRATCHL2
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; Set fill mode byte for this span
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lda SCRATCHL
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sta VRAMBANK,x
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; Cache the index we wrote to so we can erase later
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phx
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; Advance to end of span
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clc
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txa
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adc SCRATCHL2
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cmp PARAML0
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bpl renderTerrainRowSpansDone
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tax
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; Prepare for next span
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iny
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iny
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lda SCRATCHL
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eor #%110000 ; Toggle span color cache
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sta SCRATCHL
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lda terrainSpanData+2,y
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bra renderTerrainRowSpansLoop
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renderTerrainRowSpansDone:
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lda PARAML1
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dec
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bne renderTerrainSpansLoop
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pea 0 ; Null-terminate the unrender cache
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renderTerrainRowSpansSkip:
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SLOWGRAPHICS
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RESTORE_DBR
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RESTORE_AXY
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rtl
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; unrenderTerrainSpans:
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;
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;
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unrenderTerrainSpans:
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SAVE_AXY
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SAVE_DBR
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phb
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pea $e1e1 ; Work entirely in bank E1 for all local read/writes
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plb
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plb
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ldy #UNRENDERCACHESTACK-1
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unrenderTerrainSpansLoop:
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lda 0,y
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beq unrenderTerrainSpansDone
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tax
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lda #0
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sta a:0,x
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dey
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dey
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bra unrenderTerrainSpansLoop
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unrenderTerrainSpansDone:
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plb
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RESTORE_DBR
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RESTORE_AXY
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rtl
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; compileTerrainSpans:
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;
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;
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compileTerrainSpans:
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pha
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SAVE_DBR
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lda #0
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compileTerrainSpansLoop:
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sta PARAML1
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jsr compileTerrainSpansRow
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lda PARAML1
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inc
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cmp #MAXTERRAINHEIGHT
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bne compileTerrainSpansLoop
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RESTORE_DBR
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pla
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rtl
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; compileTerrainSpansRow:
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;
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; PARAML1 = Row index (bottom relative)
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;
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; Trashes SCRATCHL
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;
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compileTerrainSpansRow:
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SAVE_AXY
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lda PARAML1
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asl ; Shifts must match SPANROWBYTES
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asl
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asl
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asl
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asl
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clc
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adc #terrainSpanData
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sta SCRATCHL
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ldy #0
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ldx #TERRAINWIDTH-2
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lda terrainDataFar,x ; Figure out start value for row
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cmp PARAML1
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bcs compileTerrainSpansRowInitGreen
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compileTerrainSpansRowInitBlack:
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lda #$0010 ; First span is black
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sta (SCRATCHL) ; Initialize the row
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inc SCRATCHL
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inc SCRATCHL
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ldy #-1
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compileTerrainSpansRowBlackStart:
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iny
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compileTerrainSpansRowBlackLoop:
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lda terrainDataFar,x
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cmp PARAML1
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bcs compileTerrainSpansBlackEnd
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dex
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dex
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iny
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cpx #-2
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bne compileTerrainSpansRowBlackLoop
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compileTerrainSpansBlackEnd:
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tya ; Store this span's length
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sta (SCRATCHL)
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inc SCRATCHL
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inc SCRATCHL
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dex ; Begin searching for next span
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dex
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cpx #0
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bmi compileTerrainSpansRowDone
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ldy #0
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bra compileTerrainSpansRowGreenStart
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compileTerrainSpansRowDone:
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RESTORE_AXY
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rts
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compileTerrainSpansRowInitGreen:
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lda #$0020 ; First span is green
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sta (SCRATCHL) ; Initialize the row
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inc SCRATCHL
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inc SCRATCHL
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ldy #-1
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compileTerrainSpansRowGreenStart:
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iny
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compileTerrainSpansRowGreenLoop:
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lda terrainDataFar,x
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cmp PARAML1
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bcc compileTerrainSpansGreenEnd
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dex
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dex
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iny
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cpx #-2
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bne compileTerrainSpansRowGreenLoop
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compileTerrainSpansGreenEnd:
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tya ; Store this span's length
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sta (SCRATCHL)
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inc SCRATCHL
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inc SCRATCHL
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dex ; Begin searching for next span
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dex
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cpx #0
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bmi compileTerrainSpansRowDone
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ldy #0
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bra compileTerrainSpansRowBlackStart
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terrainSpanData:
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.repeat MAXTERRAINHEIGHT
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.word 0 ; Start value (0=BG)
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.repeat MAXSPANSPERROW
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.word 0 ; Length (in bytes)
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.endrepeat
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.endrepeat
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vramRowInvertedSpanLookup = $16C0 ; This table is copied to here by the loader
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.export renderTerrainSpans
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.export unrenderTerrainSpans
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.export compileTerrainSpans
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; Suppress some linker warnings - Must be the last thing in the file
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.SEGMENT "ZPSAVE"
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.SEGMENT "EXEHDR"
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.SEGMENT "STARTUP"
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.SEGMENT "INIT"
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.SEGMENT "LOWCODE"
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