implement belts are now added to the build queue

src/lib/sim/BuildingSystem.cpp

@@ -202,28 +202,6 @@ EntityId BuildingSystem::place(BuildingType type, QPoint anchor,
 {
     const EntityId id = m_allocateId();
 
-    if (type == BuildingType::Belt)
-    {
-        m_belts.placeBelt(anchor, rotation);
-        m_tileOccupancy[{anchor.x(), anchor.y()}] = id;
-        m_beltEntities[id] = BeltEntry{anchor, BuildingType::Belt, rotation, rotation};
-        return id;
-    }
-
-    if (type == BuildingType::Splitter)
-    {
-        const BuildingDef* def = findBuildingDef(type);
-        assert(def != nullptr);
-        const ParsedSurfaceMask mask = parseSurfaceMask(def->surfaceMask, rotation);
-        assert(mask.outputPorts.size() >= 2);
-        const Rotation outA = mask.outputPorts[0].direction;
-        const Rotation outB = mask.outputPorts[1].direction;
-        m_belts.placeSplitter(anchor, outA, outB);
-        m_tileOccupancy[{anchor.x(), anchor.y()}] = id;
-        m_beltEntities[id] = BeltEntry{anchor, BuildingType::Splitter, outA, outB};
-        return id;
-    }
-
     const BuildingDef* def = findBuildingDef(type);
     assert(def != nullptr);
     const ParsedSurfaceMask mask = parseSurfaceMask(def->surfaceMask, rotation);
@@ -403,7 +381,25 @@ void BuildingSystem::tickConstruction(Tick currentTick)
         return;
     }
 
-    // Promote construction site to operational building.
+    // Promote construction site — belts/splitters go into BeltSystem, others become Buildings.
+    if (front.type == BuildingType::Belt)
+    {
+        m_belts.placeBelt(front.anchor, front.rotation);
+        m_beltEntities[front.id] = BeltEntry{front.anchor, BuildingType::Belt, front.rotation, front.rotation};
+    }
+    else if (front.type == BuildingType::Splitter)
+    {
+        const BuildingDef* def = findBuildingDef(front.type);
+        assert(def != nullptr);
+        const ParsedSurfaceMask mask = parseSurfaceMask(def->surfaceMask, front.rotation);
+        assert(mask.outputPorts.size() >= 2);
+        const Rotation outA = mask.outputPorts[0].direction;
+        const Rotation outB = mask.outputPorts[1].direction;
+        m_belts.placeSplitter(front.anchor, outA, outB);
+        m_beltEntities[front.id] = BeltEntry{front.anchor, BuildingType::Splitter, outA, outB};
+    }
+    else
+    {
         const BuildingDef* def = findBuildingDef(front.type);
         const ParsedSurfaceMask mask = parseSurfaceMask(
             def ? def->surfaceMask : std::vector<std::string>{},
@@ -449,6 +445,8 @@ void BuildingSystem::tickConstruction(Tick currentTick)
         }
 
         m_buildings.push_back(std::move(building));
+    }
+
     m_constructionQueue.pop_front();
 
     // Start next queued site if present.

src/test/BuildingTest.cpp

@@ -92,7 +92,8 @@ TEST_CASE("BuildingSystem: place miner occupies expected body tiles", "[building
     REQUIRE_FALSE(bs.isTileOccupied(QPoint(1, 1)));
 }
 
-TEST_CASE("BuildingSystem: placing a belt registers it with BeltSystem", "[building]")
+TEST_CASE("BuildingSystem: placing a belt registers it with BeltSystem after construction",
+          "[building]")
 {
     const GameConfig cfg = loadConfig();
     BeltSystem belts(cfg.world.beltSpeedTilesPerSecond);
@@ -107,6 +108,13 @@ TEST_CASE("BuildingSystem: placing a belt registers it with BeltSystem", "[build
 
     bs.place(BuildingType::Belt, QPoint(5, 5), Rotation::East, 0);
 
+    // Belt is queued — not yet in BeltSystem.
+    REQUIRE_FALSE(belts.tryPutItem(QPoint(5, 5), makeItem("iron_ore")));
+
+    // Complete construction (1 s).
+    Tick tick = 0;
+    runTicks(bs, belts, static_cast<int>(secondsToTicks(1.0)) + 1, tick);
+
     REQUIRE(belts.tryPutItem(QPoint(5, 5), makeItem("iron_ore")));
     REQUIRE(bs.allBuildings().empty());  // belts do not create Building instances
 }