222 lines
6.6 KiB
NASM
222 lines
6.6 KiB
NASM
AdjustTransition:
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{
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lda.b $ab : and.w #$01ff : beq .reset
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phy : ldy.b #$06 ; operating on vertical registers during horizontal trans
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cpx.b #$02 : bcs .horizontalScrolling
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ldy.b #$00 ; operate on horizontal regs during vert trans
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.horizontalScrolling
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cmp.w #$0008 : bcs +
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pha : lda.b $ab : and.w #$0200 : beq ++
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pla : bra .add
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++ pla : eor.w #$ffff : inc ; convert to negative
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.add jsr AdjustCamAdd : ply : bra .reset
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+ lda.b $ab : and.w #$0200 : xba : tax
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lda.l OffsetTable,x : jsr AdjustCamAdd
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lda.b $ab : !SUB.w #$0008 : sta.b $ab
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ply : bra .done
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.reset ; clear the $ab variable so to not disturb intra-tile doors
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stz.b $ab
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.done
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lda.b Scrap00 : and.w #$01fc
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rtl
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}
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AdjustCamAdd:
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!ADD.w $00E2,y : pha
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and.w #$01ff : cmp.w #$0111 : !BLT +
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cmp.w #$01f8 : !BGE ++
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pla : and.w #$ff10 : pha : bra +
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++ pla : and.w #$ff00 : !ADD.w #$0100 : pha
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+ pla : sta.w $00E2,y : sta.w $00E0,y : rts
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; expects target quad in $05 (either 0 or 1) and target pixel in $04, target room should be in $a0
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; $06 is either $ff or $01/02
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; uses $00-$03 and $0e for calculation
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; also set up $ac
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ScrollY: ;change the Y offset variables
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lda.b RoomIndex : and.b #$f0 : lsr #3 : sta.w $0603 : inc : sta.w $0607
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lda.b Scrap05 : bne +
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lda.w $0603 : sta.b Scrap00 : stz.b Scrap01 : bra ++
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+ lda.w $0607 : sta.b Scrap00 : lda.b #$02 : sta.b Scrap01
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++ ; $01 now contains 0 or 2 and $00 contains the correct lat
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stz.b Scrap0E
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rep #$30
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lda.b Scrap00 : pha
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lda.b BG2V : and.w #$01ff : sta.b Scrap02
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lda.b Scrap04 : jsr LimitYCamera : sta.b Scrap00
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jsr CheckRoomLayoutY : bcc +
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lda.b Scrap00 : cmp.w #$0080 : !BGE ++
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cmp.w #$0010 : !BLT .cmpSrll
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lda.w #$0010 : bra .cmpSrll
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++ cmp.w #$0100 : !BGE .cmpSrll
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lda.w #$0100
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.cmpSrll sta.b Scrap00
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; figures out scroll amt
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+ lda.b Scrap00 : cmp.b Scrap02 : bne +
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lda.w #$0000 : bra .next
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+ !BLT +
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!SUB.b Scrap02 : inc.b Scrap0E : bra .next
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+ lda.b Scrap02 : !SUB.b Scrap00
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.next
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sta.b $ab
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jsr AdjustCameraBoundsY
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pla : sta.b Scrap00
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sep #$30
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lda.b Scrap04 : sta.b $20
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lda.b Scrap00 : sta.b $21 : sta.w $0601 : sta.w $0605
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lda.b Scrap01 : sta.b $aa
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lda.b Scrap0E : asl : ora.b $ac : sta.b $ac
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lda.b BG2V+1 : and.b #$01 : asl #2 : tax : lda.w $0603, x : sta.b BG2V+1
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rts
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LimitYCamera:
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cmp.w #$006c : !BGE +
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lda.w #$0000 : bra .end
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+ cmp.w #$017d : !BLT +
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lda.w #$0110 : bra .end
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+ !SUB.w #$006c
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.end rts
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CheckRoomLayoutY:
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jsr LoadRoomLayout ;switches to 8-bit
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cmp.b #$00 : beq .lock
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cmp.b #$07 : beq .free
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cmp.b #$01 : beq .free
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cmp.b #$04 : !BGE .lock
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cmp.b #$02 : bne +
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lda.b Scrap06 : cmp.b #$ff : beq .lock
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+ cmp.b #$03 : bne .free
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lda.b Scrap06 : cmp.b #$ff : bne .lock
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.free rep #$30 : clc : rts
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.lock rep #$30 : sec : rts
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AdjustCameraBoundsY:
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jsr CheckRoomLayoutY : bcc .free
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; layouts that are camera locked (quads only)
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lda.b Scrap04 : and.w #$00ff : cmp.w #$007d : !BLT +
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lda.w #$0088 : bra ++
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+ cmp.w #$006d : !BGE +
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lda.w #$0078 : bra ++
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+ !ADD.w #$000b
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; I think we no longer need the $02 variable
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++ sta.b Scrap02 : lda.b Scrap04 : and.w #$0100 : !ADD.b Scrap02 : bra .setBounds
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; layouts where the camera is free
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.free lda.b Scrap04 : cmp.w #$006c : !BGE +
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lda.w #$0077 : bra .setBounds
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+ cmp.w #$017c : !BLT +
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lda.w #$0187 : bra .setBounds
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+ !ADD.w #$000b
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.setBounds sta.w $0618 : inc #2 : sta.w $061a
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rts
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LoadRoomLayout:
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lda.b RoomIndex : asl : !ADD.b RoomIndex : tax
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lda.l RoomData_ObjectDataPointers+1, x : sta.b $b8
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lda.l RoomData_ObjectDataPointers, x : sta.b $b7
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sep #$30
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ldy.b #$01 : lda.b [$b7], y : and.b #$1c : lsr #2
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rts
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; expects target quad in $05 (either 0 or 1) and target pixel in $04, target room should be in $a0
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; uses $00-$03 and $0e for calculation
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; also set up $ac
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ScrollX: ;change the X offset variables
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lda.b RoomIndex : and.b #$0f : asl : sta.w $060b : inc : sta.w $060f
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lda.b Scrap05 : bne +
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lda.w $060b : sta.b Scrap00 : stz.b Scrap01 : bra ++
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+ lda.w $060f : sta.b Scrap00 : lda.b #$01 : sta.b Scrap01
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++ ; $01 now contains 0 or 1 and $00 contains the correct long
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stz.b Scrap0E ; pos/neg indicator
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rep #$30
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lda.b Scrap00 : pha
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lda.b BG2H : and.w #$01ff : sta.b Scrap02
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lda.b Scrap04 : jsr LimitXCamera : sta.b Scrap00
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jsr CheckRoomLayoutX : bcc +
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lda.b Scrap00 : cmp.w #$0080 : !BGE ++
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lda.w #$0000 : bra .cmpSrll
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++ lda.w #$0100
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.cmpSrll sta.b Scrap00
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;figures out scroll amt
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+ lda.b Scrap00 : cmp.b Scrap02 : bne +
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lda.w #$0000 : bra .next
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+ !BLT +
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!SUB.b Scrap02 : inc.b Scrap0E : bra .next
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+ lda.b Scrap02 : !SUB.b Scrap00
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.next
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sta.b $ab : lda.b Scrap04
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cmp.w #$0078 : !BGE +
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lda.w #$007f : bra ++
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+ cmp.w #$0178 : !BLT +
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lda.w #$017f : bra ++
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+ !ADD.w #$0007
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++ sta.w $061c : inc #2 : sta.w $061e
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pla : sta.b Scrap00
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sep #$30
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lda.b Scrap04 : ldx.w $046d : bne .straight
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sta.b LinkPosX : bra +
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.straight
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sta.w $046d ; set X position later
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+
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lda.b Scrap00 : sta.b LinkPosX+1 : sta.w $0609 : sta.w $060d
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lda.b Scrap01 : sta.b LinkQuadrantH
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lda.b Scrap0E : asl : ora.b $ac : sta.b $ac
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lda.b BG2H+1 : and.b #$01 : asl #2 : tax : lda.w $060b, x : sta.b BG2H+1
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rts
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LimitXCamera:
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cmp.w #$0079 : !BGE +
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lda.w #$0000 : bra .end
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+ cmp.w #$0178 : !BLT +
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lda.w #$0178
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+ !SUB.w #$0078
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.end rts
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CheckRoomLayoutX:
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jsr LoadRoomLayout ;switches to 8-bit
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cmp.b #$04 : !BLT .lock
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cmp.b #$05 : bne +
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lda.b Scrap06 : cmp.b #$ff : beq .lock
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+ cmp.b #$06 : bne .free
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lda.b Scrap06 : cmp.b #$ff : bne .lock
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.free rep #$30 : clc : rts
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.lock rep #$30 : sec : rts
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ApplyScroll:
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rep #$30
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lda.b $ab : and.w #$01ff : sta.b Scrap00
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lda.b $ab : and.w #$0200 : beq +
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lda.w $00e2, y : !ADD.b Scrap00 : bra .end
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+ lda.w $00e2, y : !SUB.b Scrap00
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.end
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sta.w $00e2, y
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sta.w $00e0, y
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stz.b $ab : sep #$30 : rts
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QuadrantLoadOrderBeforeScroll:
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lda.w $045f : beq .end
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lda.b #$08 : sta.w $045c ; start with opposite quadrant row
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.end
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JML WaterFlood_BuildOneQuadrantForVRAM ; what we overwrote
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QuadrantLoadOrderAfterScroll:
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lda.w $045f : beq .end
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stz.w $045c : stz.w $045f ; draw other row and clear flag
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.end
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JML WaterFlood_BuildOneQuadrantForVRAM ; what we overwrote |