Minecart refactoring, break up collision handling into multiple fns

Sprites/Objects/minecart.asm

@@ -121,6 +121,7 @@ Sprite_Minecart_Prep:
   STZ.w SprBump, X                ; No bump damage
   STZ.w SprTileDie, X             ; Set interactive hitbox
   STZ.w !MinecartDirection
+  STZ.w !SpriteDirection, X
 
   LDA.w SprSubtype, X : CMP.b #$00 : BEQ .north
                         CMP.b #$01 : BEQ .east
@@ -452,37 +453,26 @@ Sprite_Minecart_Main:
 
 ; =========================================================
 
-HandleTileDirections:
+CheckForOutOfBounds:
 {
-  LDA.w SprTimerA, X : BEQ +
+  LDA $0FA5
-    RTS
-  +
-
-  ; If the cart got disconnected from the player, release them.
-  JSR CheckIfPlayerIsOn : BCS .player_on_cart
-    %GotoAction(6) ; Minecart_Release
-    RTS
-  .player_on_cart
-
-  ; Setup Minecart position to look for tile IDs
-  ; We use AND #$F8 to clamp to a 16x16 grid, however this needs work.
-  LDA.w SprY, X : AND #$F8 : STA.b $00 : LDA.w SprYH, X : STA.b $01
-  LDA.w SprX, X : AND #$F8 : STA.b $02 : LDA.w SprXH, X : STA.b $03
-
-  ; Fetch tile attributes based on current coordinates
-  LDA.b #$00 : JSL Sprite_GetTileAttr : LDA $0FA5
   CMP.b #$02 : BNE .not_out_of_bounds
     ; If the tile is out of bounds, release the cart
     LDA #$40 : STA.w SprTimerD, X
     %GotoAction(6) ; Minecart_Release
     RTS
   .not_out_of_bounds
+  RTS
+}
+
+CheckForStopTiles:
+{
   ; Check if the tile is a stop tile
   CMP.b #$B7 : BEQ .stop_north
   CMP.b #$B8 : BEQ .stop_south
   CMP.b #$B9 : BEQ .stop_west
   CMP.b #$BA : BEQ .stop_east
-  JMP .check_for_movement ; if none of the above, continue with normal logic
+  JMP +
 
   .stop_north
     ; Set the new direction to north and flip the cart's orientation
@@ -493,7 +483,6 @@ HandleTileDirections:
     ; Set the new direction to south and flip the cart's orientation
     LDA.b #North : STA.w SprSubtype, X : STZ.w !MinecartDirection
     LDA.b #Up  : STA !SpriteDirection, X
-  ; -----------------------------------------------
   .go_vert
     %SetTimerA($40)
     %StopCart()
@@ -509,44 +498,23 @@ HandleTileDirections:
     ; Set the new direction to west and flip the cart's orientation
     LDA.b #East : STA.w SprSubtype, X : STA.w !MinecartDirection
     LDA.b #Right  : STA !SpriteDirection, X
-  ; -----------------------------------------------
   .go_horiz
     %SetTimerA($40)
     %StopCart()
     %GotoAction(0) ; Minecart_WaitHoriz
     JSL Link_ResetProperties_A
+  +
   RTS
+}
 
-  ; -----------------------------------------------------
+CheckForCornerTiles:
-  .check_for_movement
+{
   CMP.b #$B2 : BEQ .check_direction
   CMP.b #$B3 : BEQ .check_direction
   CMP.b #$B4 : BEQ .check_direction
   CMP.b #$B5 : BEQ .check_direction
-    CMP.b #$B0 : BEQ .horiz
+    SEC
-    CMP.b #$B1 : BEQ .vert
+    RTS
-    CMP.b #$BB : BEQ .horiz
-    CMP.b #$BC : BEQ .vert
-      JMP .done
-
-    .horiz
-      ; Are we moving left or right?
-      LDA.w SprSubtype, X : CMP.b #$03 : BEQ .inverse_horiz_velocity
-        LDA.b #!MinecartSpeed : STA.w SprXSpeed, X
-        LDA.b #East : STA !MinecartDirection
-        JMP .done
-      .inverse_horiz_velocity
-        LDA.b #-!MinecartSpeed : STA.w SprXSpeed, X
-        LDA.b #West : STA !MinecartDirection
-        JMP .done
-    .vert
-      ; Are we moving up or down?
-      LDA.w SprSubtype, X : CMP.b #$00 : BEQ .inverse_vert_velocity
-        LDA.b #!MinecartSpeed : STA.w SprYSpeed, X
-        JMP .done
-      .inverse_vert_velocity
-      LDA.b #-!MinecartSpeed : STA.w SprYSpeed, X
-      JMP .done
   .check_direction
   LDA.w SprSubtype, X
   ASL #2  ; Multiply by 4 to offset rows in the lookup table
@@ -589,7 +557,7 @@ HandleTileDirections:
     LDA.w SprY, X : AND #$F8 : STA.w SprY, X
     %GotoAction(5) ; Minecart_MoveWest
   .done
-    LDA #$0F : STA.w SprTimerA, X
+  CLC
   RTS
 
   ; Direction to move on tile collision
@@ -608,6 +576,63 @@ HandleTileDirections:
   }
 }
 
+CheckForTrackTiles:
+{
+  CMP.b #$B0 : BEQ .horiz
+  CMP.b #$B1 : BEQ .vert
+  CMP.b #$BB : BEQ .horiz
+  CMP.b #$BC : BEQ .vert
+    JMP .done
+
+  .horiz
+  ; Are we moving left or right?
+  LDA.w SprSubtype, X : CMP.b #$03 : BEQ .inverse_horiz_velocity
+    LDA.b #!MinecartSpeed : STA.w SprXSpeed, X
+    LDA.b #East : STA !MinecartDirection
+    JMP .done
+  .inverse_horiz_velocity
+  LDA.b #-!MinecartSpeed : STA.w SprXSpeed, X
+  LDA.b #West : STA !MinecartDirection
+  JMP .done
+  .vert
+  ; Are we moving up or down?
+  LDA.w SprSubtype, X : CMP.b #$00 : BEQ .inverse_vert_velocity
+    LDA.b #!MinecartSpeed : STA.w SprYSpeed, X
+    JMP .done
+  .inverse_vert_velocity
+  LDA.b #-!MinecartSpeed : STA.w SprYSpeed, X
+  .done
+  RTS
+}
+
+HandleTileDirections:
+{
+  LDA.w SprTimerA, X : BEQ +
+    RTS
+  +
+
+  ; If the cart got disconnected from the player, release them.
+  JSR CheckIfPlayerIsOn : BCS .player_on_cart
+    %GotoAction(6) ; Minecart_Release
+    RTS
+  .player_on_cart
+
+  ; Setup Minecart position to look for tile IDs
+  ; We use AND #$F8 to clamp to a 16x16 grid, however this needs work.
+  LDA.w SprY, X : AND #$F8 : STA.b $00 : LDA.w SprYH, X : STA.b $01
+  LDA.w SprX, X : AND #$F8 : STA.b $02 : LDA.w SprXH, X : STA.b $03
+
+  ; Fetch tile attributes based on current coordinates
+  LDA.b #$00 : JSL Sprite_GetTileAttr
+  JSR CheckForOutOfBounds
+  JSR CheckForStopTiles
+  JSR CheckForCornerTiles : BCC .done
+  JSR CheckForTrackTiles
+  .done
+  LDA #$0F : STA.w SprTimerA, X
+  RTS
+}
+
 ; =========================================================
 ; Check for the switch_track sprite and move based on the
 ; state of that sprite.