allow to inspect balancing arena

src/balancing/ArenaView.h

@@ -0,0 +1,79 @@
+#pragma once
+
+#include <random>
+#include <vector>
+
+#include <QElapsedTimer>
+#include <QOpenGLWidget>
+#include <QTimer>
+#include <QVector2D>
+
+#include "EntityId.h"
+#include "FireEvent.h"
+#include "Tick.h"
+#include "TickDriver.h"
+#include "VisualsConfig.h"
+
+class ArenaSimulation;
+class QPainter;
+
+class ArenaView : public QOpenGLWidget
+{
+    Q_OBJECT
+
+public:
+    ArenaView(ArenaSimulation* sim, const VisualsConfig* visuals,
+              QWidget* parent = nullptr);
+
+    void setGameSpeed(double multiplier);
+    double gameSpeed() const;
+    void togglePause();
+
+signals:
+    void speedChanged(double multiplier);
+    void finished();
+
+protected:
+    void paintGL() override;
+
+private slots:
+    void onFrame();
+
+private:
+    void drawTiles(QPainter& painter);
+    void drawBuildings(QPainter& painter);
+    void drawScrap(QPainter& painter);
+    void drawShips(QPainter& painter);
+    void drawBeams(QPainter& painter);
+
+    float tilePx() const;
+    QPointF worldToWidget(QVector2D worldPos) const;
+    QPointF tileToWidget(QPoint tile) const;
+    QRectF tileRect(QPoint tile) const;
+
+    std::optional<QVector2D> entityPosition(EntityId id) const;
+
+    struct ActiveBeam
+    {
+        FireEvent event;
+        qint64    emittedWallMs;
+        QVector2D targetOffset;
+    };
+
+    static constexpr qint64 kBeamLifetimeMs = 300;
+
+    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;
+
+    QTimer* m_renderTimer;
+
+    std::vector<ActiveBeam> m_activeBeams;
+    bool m_finishedEmitted;
+};