fix issue where beams were also disappearing while the game was paused

src/balancing/ArenaView.cpp

@@ -40,7 +40,6 @@ ArenaView::ArenaView(ArenaSimulation* sim, const VisualsConfig* visuals,
     : QOpenGLWidget(parent)
     , m_sim(sim)
     , m_visuals(visuals)
-    , m_wallMs(0)
     , m_gameSpeedMultiplier(1.0)
     , m_prevNonZeroSpeed(1.0)
     , m_rng(std::random_device{}())
@@ -99,7 +98,6 @@ void ArenaView::togglePause()
 void ArenaView::onFrame()
 {
     const qint64 elapsed = m_frameTimer.restart();
-    m_wallMs += elapsed;
 
     {
         const int ticks = m_tickDriver.advance(
@@ -120,12 +118,14 @@ void ArenaView::onFrame()
         }
     }
 
-    // Expire old beams
+    // Expire old beams. Lifetime is measured in game ticks so beams stay
+    // visible while the simulation is paused or slowed (REQ-SHP-FIRING-BEAM).
     {
+        const Tick now = m_sim->currentTick();
         std::vector<ActiveBeam> live;
         for (const ActiveBeam& b : m_activeBeams)
         {
-            if (m_wallMs - b.emittedWallMs < kBeamLifetimeMs)
+            if (now - b.event.emittedAt < kBeamLifetimeTicks)
             {
                 live.push_back(b);
             }
@@ -165,7 +165,6 @@ void ArenaView::handleEvent(std::shared_ptr<const BeamFiredEvent> event)
 
     ActiveBeam beam;
     beam.event         = *event;
-    beam.emittedWallMs = m_wallMs;
     beam.targetOffset  = QVector2D(radius * std::cos(angle),
                                    radius * std::sin(angle));
     m_activeBeams.push_back(beam);

src/balancing/ArenaView.h

@@ -67,18 +67,18 @@ private:
     struct ActiveBeam
     {
         BeamFiredEvent event;
-        qint64    emittedWallMs;
         QVector2D targetOffset;
     };
 
-    static constexpr qint64 kBeamLifetimeMs = 300;
+    // Beam lifetime in game ticks so beams freeze with the simulation when
+    // paused or slowed, instead of fading on wall-clock time (REQ-SHP-FIRING-BEAM).
+    static constexpr Tick kBeamLifetimeTicks = secondsToTicks(0.3);
 
     ArenaSimulation*     m_sim;
     const VisualsConfig* m_visuals;
 
     TickDriver    m_tickDriver;
     QElapsedTimer m_frameTimer;
-    qint64        m_wallMs;
     std::mt19937  m_rng;
     double        m_gameSpeedMultiplier;
     double        m_prevNonZeroSpeed;

src/ui/GameWorldView.cpp

@@ -102,7 +102,6 @@ GameWorldView::GameWorldView(Simulation* sim, const GameConfig* config,
     , m_sim(sim)
     , m_config(config)
     , m_visuals(visuals)
-    , m_wallMs(0)
     , m_gameSpeedMultiplier(1.0)
     , m_prevNonZeroSpeed(1.0)
     , m_scrollXTiles(0.0f)
@@ -144,7 +143,6 @@ void GameWorldView::initializeGL()
 void GameWorldView::onFrame()
 {
     const qint64 elapsed = m_frameTimer.restart();
-    m_wallMs += elapsed;
 
     // Advance simulation
     {
@@ -166,12 +164,14 @@ void GameWorldView::onFrame()
         }
     }
 
-    // Expire old beams
+    // Expire old beams. Lifetime is measured in game ticks so beams stay
+    // visible while the simulation is paused or slowed (REQ-SHP-FIRING-BEAM).
     {
+        const Tick now = m_sim->currentTick();
         std::vector<ActiveBeam> live;
         for (const ActiveBeam& b : m_activeBeams)
         {
-            if (m_wallMs - b.emittedWallMs < kBeamLifetimeMs)
+            if (now - b.event.emittedAt < kBeamLifetimeTicks)
             {
                 live.push_back(b);
             }
@@ -1603,7 +1603,6 @@ void GameWorldView::handleEvent(std::shared_ptr<const BeamFiredEvent> event)
 
     ActiveBeam beam;
     beam.event         = *event;
-    beam.emittedWallMs = m_wallMs;
     beam.targetOffset  = QVector2D(radius * std::cos(angle),
                                    radius * std::sin(angle));
     m_activeBeams.push_back(beam);

src/ui/GameWorldView.h

@@ -141,11 +141,12 @@ private:
     struct ActiveBeam
     {
         BeamFiredEvent event;
-        qint64    emittedWallMs;
         QVector2D targetOffset;
     };
 
-    static constexpr qint64  kBeamLifetimeMs        = 300;
+    // Beam lifetime in game ticks so beams freeze with the simulation when
+    // paused or slowed, instead of fading on wall-clock time (REQ-SHP-FIRING-BEAM).
+    static constexpr Tick    kBeamLifetimeTicks      = secondsToTicks(0.3);
     static constexpr float   kScrollSpeedTilesPerSec = 10.0f;
 
     Simulation*          m_sim;
@@ -154,7 +155,6 @@ private:
 
     TickDriver    m_tickDriver;
     QElapsedTimer m_frameTimer;
-    qint64        m_wallMs;
     std::mt19937  m_rng;
     double        m_gameSpeedMultiplier;
     double        m_prevNonZeroSpeed;