Simulator: add singleton static instance

hcore/include/simulator/canvas.h

@@ -1,21 +0,0 @@
-#ifndef CANVAS_H
-#define CANVAS_H
-
-#include <simulator/scene.h>
-
-namespace canvas {
-
-class Canvas {
-public:
-    Canvas();
-    ~Canvas();
-
-    SceneId loadScene(Scene &scene);
-
-private:
-    // Add private members here
-};
-
-} // namespace canvas
-
-#endif // CANVAS_H

hcore/include/simulator/simulator.h

@@ -1,22 +1,30 @@
 #ifndef SIMULATOR_H
 #define SIMULATOR_H
 
-#include <simulator/canvas.h>
+#include <simulator/scene.h>
 
 namespace simulator {
 
 class Simulator {
 public:
-    Simulator();
-    ~Simulator();
+    Simulator(const Simulator&) = delete;
+    void operator=(const Simulator&) = delete;
+
+    static Simulator& instance()
+    {
+        static Simulator instance;
+        return instance;
+    }
 
     void initialize();
-    void run();
-    void stop();
+    void loadScene(scene::Scene::Id sceneId, scene::Scene &scene);
 
 private:
-    bool isRunning;
-    Canvas canvas;
+    Simulator() = default;
+    ~Simulator() = default;
+
+    scene::Scene::Id sceneId;
+    scene::Scene scene;
 };
 
 }