Update Game, add IGame.

Voile/Source/Game.cs

@@ -1,43 +1,51 @@
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using Voile.Input;
 using Voile.Rendering;
 using Voile.Resources;
 
 namespace Voile
 {
+    public interface IGame
+    {
+        string Name { get; }
+        /// <summary>
+        /// Resource root path for this game.
+        /// </summary>
+        string ResourceRoot { get; }
+        void Start();
+        void Run();
+        void Shutdown();
+    }
+
     /// <summary>
     /// Entry point for the Voile game.
     /// </summary>
-    public abstract class Game
+    public abstract class Game : IGame
     {
+        public double UpdateTimeStep { get; set; } = 1.0 / 60.0;
+        public TimeSpan UpdateFrameTime { get; private set; }
+        public TimeSpan RenderFrameTime { get; private set; }
+
         /// <summary>
         /// The ResourceManager associated with this game.
         /// </summary>
-        protected ResourceManager ResourceManager { get; private set; }
+        protected ResourceManager ResourceManager { get; private set; } = new();
         /// <summary>
         /// The InputHandler associated with this game. Uses <see cref="RaylibInputSystem"/> by default.
         /// </summary>
-        protected InputSystem Input { get; private set; }
+        protected InputSystem? Input { get; set; }
 
         /// <summary>
         /// The Renderer associated with this game. Uses <see cref="RaylibRenderSystem"/> by default.
         /// </summary>
-        protected RenderSystem Renderer { get; private set; }
-
-        /// <summary>
-        /// Resource root path for this game.
-        /// </summary>
-        public virtual string ResourceRoot => "Resources/";
-
-        /// <summary>
-        /// Path to the engine configuration file.
-        /// </summary>
-        public virtual string EngineConfigPath => "engine.config";
+        protected RenderSystem? Renderer { get; set; }
 
         /// <summary>
         /// Name of this game. Also used as a default window title.
         /// </summary>
-        public virtual string Name => "";
+        public virtual string Name => "Voile Game";
+        public virtual string ResourceRoot => "Resources/";
 
         /// <summary>
         /// Default game constructor.
@@ -45,19 +53,16 @@ namespace Voile
         public Game()
         {
             ResourceManager = new ResourceManager();
-            Input = new RaylibInputSystem();
-            Renderer = new RaylibRenderSystem();
+            Initialize();
         }
 
         /// <summary>
         /// Game constructor with custom systems.
         /// </summary>
-        /// <param name="resourceManager"></param>
         /// <param name="inputSystem"></param>
         /// <param name="renderSystem"></param>
-        public Game(ResourceManager resourceManager, InputSystem inputSystem, RenderSystem renderSystem)
+        public Game(InputSystem inputSystem, RenderSystem renderSystem)
         {
-            ResourceManager = resourceManager;
             Input = inputSystem;
             Renderer = renderSystem;
         }
@@ -83,83 +88,77 @@ namespace Voile
                 throw new NullReferenceException("No ResourceManager provided.");
             }
 
-            Initialize();
+            LoadResources();
             Ready();
             Run();
             Shutdown();
         }
 
         /// <summary>
-        /// Initializes subsystems using default types and settings.
+        /// Initializes systems using default types and settings.
         /// </summary>
-        public void InitializeDefault()
+        public void InitializeSystemsDefault()
         {
             ResourceManager.ResourceRoot = ResourceRoot;
 
-            Input = new RaylibInputSystem();
-            Renderer = new RaylibRenderSystem();
+            if (Renderer is null)
+            {
+                Renderer = new RaylibRenderSystem();
+            }
+
+            if (Input is null)
+            {
+                Input = new RaylibInputSystem();
+            }
 
             Input.Start();
-
             InitializeRenderer();
         }
 
         public void ShutdownDefault()
         {
-            Input.Dispose();
-            Renderer.Dispose();
+            Input?.Dispose();
+            Renderer?.Dispose();
             ResourceManager.Dispose();
         }
 
         /// <summary>
-        /// Called when it's time to initialize the subsystems, or modify default game settings or system settings.
+        /// Adds a system that will start together with the game.
         /// </summary>
-        public abstract void Initialize();
+        /// <param name="system"></param>
+        public void AddSystem([DisallowNull] IStartableSystem system)
+        {
+            _startableSystems.Add(system);
+        }
+
         /// <summary>
-        /// Called when it's safe to manipulate the resources or/and systems.
-        /// You can safely create game objects, scenes, etc. in this method.
+        /// Adds a system to the Update step.
         /// </summary>
-        protected abstract void Ready();
+        /// <param name="system"></param>
+        public void AddSystemToUpdate([DisallowNull] IUpdatableSystem system)
+        {
+            _updatableSystems.Add(system);
+        }
+
+        /// <summary>
+        /// Adds a system to the render step.
+        /// </summary>
+        /// <param name="system"></param>
+        public void AddSystemToRender([DisallowNull] IUpdatableSystem system)
+        {
+            _renderableSystems.Add(system);
+        }
+
         /// <summary>
         /// Called when everything has been readied to start the main loop.
         /// </summary>
-        protected abstract void Run();
-        /// <summary>
-        /// Called when the application quits and it's safe to clean up.
-        /// </summary>
-        public abstract void Shutdown();
-
-        private void InitializeRenderer()
+        public void Run()
         {
-            var windowSettings = WindowSettings.Default;
+            if (Renderer is null)
+            {
+                throw new NullReferenceException("No renderer provided.");
+            }
 
-            if (!string.IsNullOrWhiteSpace(Name))
-                windowSettings.Title = Name;
-
-            Renderer.Start(RendererSettings.Default);
-        }
-    }
-
-    public abstract class BaseGame : Game
-    {
-        public double UpdateTimeStep { get; set; } = 1.0 / 60.0;
-        public TimeSpan UpdateFrameTime { get; private set; }
-        public TimeSpan RenderFrameTime { get; private set; }
-        public override void Initialize()
-        {
-            LoadResources();
-            InitializeDefault();
-        }
-
-        public override void Shutdown() => ShutdownDefault();
-
-        /// <summary>
-        /// Called when it's time to load the game's resources, such as images or sounds.
-        /// </summary>
-        protected abstract void LoadResources();
-
-        protected override void Run()
-        {
             Stopwatch stopwatch = Stopwatch.StartNew();
             double previousTime = stopwatch.Elapsed.TotalSeconds;
 
@@ -173,11 +172,22 @@ namespace Voile
 
                 while (_accumulator >= UpdateTimeStep)
                 {
+                    foreach (var system in _updatableSystems)
+                    {
+                        system.Update(UpdateTimeStep);
+                    }
+
                     Update(UpdateTimeStep);
                     _accumulator -= UpdateTimeStep;
                 }
 
                 Renderer.BeginFrame();
+
+                foreach (var system in _renderableSystems)
+                {
+                    system.Update(Renderer.FrameTime);
+                }
+
                 Render(Renderer.FrameTime);
                 Renderer.EndFrame();
 
@@ -185,6 +195,21 @@ namespace Voile
             }
         }
 
+        /// <summary>
+        /// Called when it's time to initialize the subsystems, or modify default game settings or system settings.
+        /// </summary>
+        public abstract void Initialize();
+        /// <summary>
+        /// Called when it's safe to manipulate the resources or/and systems.
+        /// You can safely create game objects, scenes, etc. in this method.
+        /// </summary>
+        protected abstract void Ready();
+
+        /// <summary>
+        /// Called when it's time to load the game's resources, such as images or sounds.
+        /// </summary>
+        protected abstract void LoadResources();
+
         /// <summary>
         /// Triggered on each fixed timestep. Update your game's state here.
         /// </summary>
@@ -196,6 +221,28 @@ namespace Voile
         /// <param name="deltaTime"></param>
         protected abstract void Render(double deltaTime);
 
+        /// <summary>
+        /// Called when the application quits and it's safe to clean up.
+        /// </summary>
+        public abstract void Shutdown();
+
+        private void InitializeRenderer()
+        {
+            var windowSettings = WindowSettings.Default;
+
+            if (!string.IsNullOrWhiteSpace(Name))
+                windowSettings.Title = Name;
+
+            var renderSettings = RendererSettings.Default;
+            renderSettings.WindowSettings = windowSettings;
+
+            Renderer?.Start(renderSettings);
+        }
+
+        private List<IStartableSystem> _startableSystems = new();
+        private List<IUpdatableSystem> _updatableSystems = new();
+        private List<IUpdatableSystem> _renderableSystems = new();
+
         private double _accumulator;
     }
 }