implement tunnels

src/lib/sim/BeltSystem.h

@@ -37,6 +37,12 @@ public:
     // Register a new belt tile.  Any items already on this tile are cleared.
     void placeBelt(QPoint tile, Rotation direction);
 
+    // Register a new tunnel entry tile.
+    void placeTunnelEntry(QPoint tile, Rotation direction, int maxDistance);
+
+    // Register a new tunnel exit tile.
+    void placeTunnelExit(QPoint tile, Rotation direction);
+
     // Register a new splitter tile.  outputA and outputB are the two exit
     // directions (e.g. West and East for a default-rotation splitter).
     // Items entering from any adjacent belt whose direction points into this
@@ -87,13 +93,20 @@ public:
 
 private:
     void advanceProgress();
+    void advanceTunnelProgress();
     void moveItemsToNextTile();
+    void moveTunnelItems();
     void routeSplitterItems();
 
     // Place item into back slot of an existing belt tile at progress 0.
     // Returns false if tile is not a belt or is full.
     bool tryPlaceOnBelt(QPoint tile, Item item);
 
+    // Push an item to any tile type (belt, splitter, tunnel entry, tunnel exit).
+    bool tryPushToTile(QPoint dest, Item item, Rotation fromDir);
+
+    void reevaluateTunnelPairing();
+
     static std::pair<int, int> key(QPoint tile);
     static QPoint adjacentTile(QPoint tile, Rotation dir);
 
@@ -126,9 +139,41 @@ private:
         std::optional<BeltItemSlot> frontB;  // progress [0, 1]; routed to outputB
     };
 
+    struct TunnelEntryTile
+    {
+        Rotation direction;
+        int maxDistance;
+        std::optional<BeltItemSlot> front;
+        std::optional<BeltItemSlot> back;
+    };
+
+    struct TunnelExitTile
+    {
+        Rotation direction;
+        std::optional<BeltItemSlot> front;
+        std::optional<BeltItemSlot> back;
+    };
+
+    struct TunnelTransitItem
+    {
+        Item item;
+        double progress;
+    };
+
+    struct TunnelLink
+    {
+        QPoint entryTile;
+        QPoint exitTile;
+        double length;
+        std::vector<TunnelTransitItem> items;  // front (highest progress) to back
+    };
+
     double m_progressPerTick;  // beltSpeedTilesPerSecond / kTickRateHz
 
-    std::map<std::pair<int, int>, BeltTile>     m_belts;
-    std::map<std::pair<int, int>, SplitterTile> m_splitters;
+    std::map<std::pair<int, int>, BeltTile>        m_belts;
+    std::map<std::pair<int, int>, SplitterTile>    m_splitters;
+    std::map<std::pair<int, int>, TunnelEntryTile> m_tunnelEntries;
+    std::map<std::pair<int, int>, TunnelExitTile>  m_tunnelExits;
+    std::vector<TunnelLink>                        m_tunnelLinks;
 };