add restart button to game over screen

src/lib/sim/Simulation.cpp

@@ -49,6 +49,45 @@ Simulation::Simulation(const GameConfig& config, unsigned int seed)
 
 Simulation::~Simulation() = default;
 
+void Simulation::reset(unsigned int seed)
+{
+    m_rng.seed(seed);
+    m_currentTick              = 0;
+    m_nextId                   = 1;
+    m_buildingBlocksStock      = m_config.world.startingBuildingBlocks;
+    m_gameOver                 = false;
+    m_hqId                     = kInvalidEntityId;
+    m_playerStation1Id         = kInvalidEntityId;
+    m_playerStation2Id         = kInvalidEntityId;
+    m_currentEnemyStationIds[0] = kInvalidEntityId;
+    m_currentEnemyStationIds[1] = kInvalidEntityId;
+    m_fireEvents.clear();
+    m_blueprintDropEvents.clear();
+
+    m_beltSystem = BeltSystem(m_config.world.beltSpeedTilesPerSecond);
+    m_buildingSystem = std::make_unique<BuildingSystem>(
+        m_config,
+        m_beltSystem,
+        [this]() { return allocateId(); },
+        [this](int amount) { m_buildingBlocksStock += amount; },
+        m_rng);
+    m_shipSystem  = std::make_unique<ShipSystem>(m_config, [this]() { return allocateId(); });
+    m_scrapSystem = std::make_unique<ScrapSystem>([this]() { return allocateId(); });
+    m_waveSystem  = std::make_unique<WaveSystem>(m_config, m_rng);
+    m_combatSystem = std::make_unique<CombatSystem>(m_config);
+
+    m_blueprintLevels.clear();
+    for (const ShipDef& def : m_config.ships.ships)
+    {
+        BlueprintState state;
+        state.unlocked = def.availableFromStart;
+        state.level    = def.availableFromStart ? def.blueprint.playerProductionLevel : 0;
+        m_blueprintLevels[def.id] = state;
+    }
+
+    placeInitialStructures();
+}
+
 // ---------------------------------------------------------------------------
 // tick
 // ---------------------------------------------------------------------------

src/lib/sim/Simulation.h

@@ -29,6 +29,9 @@ public:
     explicit Simulation(const GameConfig& config, unsigned int seed = 0);
     ~Simulation();
 
+    // Reinitializes all simulation state as if constructed fresh.
+    void reset(unsigned int seed = 0);
+
     // Advances the simulation by one tick. Tick order per architecture.md §Tick Order.
     void tick();
 

src/ui/GameWorldView.cpp

@@ -1121,3 +1121,24 @@ void GameWorldView::setGameSpeed(double multiplier)
                       m_sim->buildingBlocksStock(),
                       m_gameSpeedMultiplier);
 }
+
+void GameWorldView::resetForNewGame()
+{
+    exitBuilderMode();
+    m_activeBeams.clear();
+    m_toasts.clear();
+    m_ghostRotation    = Rotation::East;
+    m_ghostValid       = false;
+    m_demolishMode     = false;
+    m_demolishHoverId  = kInvalidEntityId;
+    m_selectedIds.clear();
+    m_boxSelecting     = false;
+    m_scrollXTiles     = 0.0f;
+    m_scrollLeft       = false;
+    m_scrollRight      = false;
+    m_gameOverShown    = false;
+    m_gameSpeedMultiplier  = 1.0;
+    m_prevNonZeroSpeed     = 1.0;
+    emit selectionChanged({});
+    update();
+}

src/ui/GameWorldView.h

@@ -51,6 +51,7 @@ public slots:
     void enterBuilderMode(BuildingType type);
     void exitBuilderMode();
     void setGameSpeed(double multiplier);
+    void resetForNewGame();
 
 protected:
     void initializeGL() override;

src/ui/MainWindow.cpp

@@ -2,6 +2,7 @@
 
 #include <QHBoxLayout>
 #include <QMessageBox>
+#include <QPushButton>
 #include <QResizeEvent>
 #include <QVBoxLayout>
 
@@ -106,7 +107,17 @@ void MainWindow::onGameOver()
     box.setText(QString("HQ destroyed!\nSurvival time: %1:%2")
         .arg(minutes, 2, 10, QChar('0'))
         .arg(seconds, 2, 10, QChar('0')));
+    QPushButton* restartBtn = box.addButton("Restart", QMessageBox::AcceptRole);
     box.addButton("Quit", QMessageBox::RejectRole);
     box.exec();
-    close();
+
+    if (box.clickedButton() == restartBtn)
+    {
+        m_sim->reset();
+        m_gameWorldView->resetForNewGame();
+    }
+    else
+    {
+        close();
+    }
 }