Improve transition animation from straight stairs

doorrando.asm

@@ -9,6 +9,7 @@
 ; Normal doors use $FE to store the trap door indicator
 ; Normal doors use $045e to store Y coordinate when transitioning to in-room stairs
 ; Normal doors use $045f to determine the order in which supertile quadrants are drawn
+; Straight stairs use $046d to store X coordinate on animation start
 ; Spiral doors use $045e to store stair type
 ; Gfx uses $b1 to for sub-sub-sub-module thing
 

normal.asm

@@ -150,15 +150,14 @@ LoadRoomVert:
     .notEdge
     lda $01 : and #$03 : cmp #$03 : bne .normal
         jsr ScrollToInroomStairs
+        stz $046d
         bra .end
     .normal
 	ldy #$01 : jsr ShiftVariablesMainDir
     jsr PrepScrollToNormal
     .scroll
-    lda $01 : and #$40 : pha
+    lda $01 : and #$40 : sta $046d
     jsr ScrollX
-    pla : beq .end
-        ldy #$00 : jsr ApplyScroll
     .end
     plb ; restore db register
     rts
@@ -291,6 +290,11 @@ StraightStairsAdj:
     stx $0464 : sty $012e ; what we wrote over
     lda.l DRMode : beq +
         lda $045e : bne .toInroom
+        lda $046d : beq .noScroll
+            sta $22
+            ldy #$00 : jsr ApplyScroll
+            stz $046d
+        .noScroll
         jsr GetTileAttribute : tax
         lda $11 : cmp #$12 : beq .goingNorth
             lda $a2 : cmp #$51 : bne ++

scroll.asm

@@ -168,7 +168,11 @@ ScrollX: ;change the X offset variables
 
     pla : sta $00
     sep #$30
-    lda $04 : sta $22
+    lda $04 : ldx $046d : bne .straight
+        sta $22 : bra +
+    .straight
+        sta $046d ; set X position later
+    +
     lda $00 : sta $23 : sta $0609 : sta $060d
     lda $01 : sta $a9
     lda $0e : asl : ora $ac : sta $ac