; ; 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 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 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: .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 .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"