Add some more simple systems.

Generate Assets.cs with generate-asset-class.js
Currently only processes Images/ in the .mgcb

Makefile

@@ -0,0 +1,3 @@
+generate-assets-class:
+	test -f MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Content/MonoGameBlank2dStartKit.mgcb || exit 1
+	node ./generate-asset-class.js MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Content/MonoGameBlank2dStartKit.mgcb > MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Content/Assets.cs

MonoGameBlank2dStartKit.sln.DotSettings.user

@@ -3,4 +3,5 @@
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003AGameTime_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2025_002E1_003Fresharper_002Dhost_003FDecompilerCache_003Fdecompiler_003F607c842ed163400ca987bebdb007e915137000_003F19_003F2ed69731_003FGameTime_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003AGame_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2025_002E1_003Fresharper_002Dhost_003FDecompilerCache_003Fdecompiler_003F607c842ed163400ca987bebdb007e915137000_003Fe8_003Fc288a217_003FGame_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003APath_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2025_002E1_003Fresharper_002Dhost_003FDecompilerCache_003Fdecompiler_003Fbf07be36dfaa4f47b843d44a6617c8b9d19e00_003Fab_003Ffafcbf34_003FPath_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
-	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003ASpriteBatch_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2025_002E1_003Fresharper_002Dhost_003FDecompilerCache_003Fdecompiler_003F607c842ed163400ca987bebdb007e915137000_003Fa6_003F45905159_003FSpriteBatch_002Ecs/@EntryIndexedValue">ForceIncluded</s:String></wpf:ResourceDictionary>
+	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003ASpriteBatch_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2025_002E1_003Fresharper_002Dhost_003FDecompilerCache_003Fdecompiler_003F607c842ed163400ca987bebdb007e915137000_003Fa6_003F45905159_003FSpriteBatch_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
+	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003ATimeSpan_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2025_002E1_003Fresharper_002Dhost_003FDecompilerCache_003Fdecompiler_003Fbf07be36dfaa4f47b843d44a6617c8b9d19e00_003F2e_003F2f4498f0_003FTimeSpan_002Ecs/@EntryIndexedValue">ForceIncluded</s:String></wpf:ResourceDictionary>

MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Components.cs

@@ -1,9 +1,34 @@
+using System;
 using System.Numerics;
+using Microsoft.Xna.Framework.Graphics;
 using MonoGameBlank2dStartKit.Core.Content;
 
 namespace MonoGameBlank2dStartKit.Core;
 
-public readonly record struct Position(Vector2 Vector2);
+public readonly record struct Position(Vector2 Vector2)
-public readonly record struct Velocity(Vector2 Vector2);
+{
+    public Position(float x, float y) : this(new Vector2(x, y)) { }
+}
+
+public readonly record struct Velocity(Vector2 Vector2)
+{
+    public Velocity(float x, float y) : this(new Vector2(x, y)) { }
+}
+
+public readonly record struct Mass(int Value);
+
+public readonly record struct RotationSpeed(float Speed, float Amount = float.MaxValue, float Drag = 0)
+{
+}
+
+public readonly record struct Rotation(float Value, Vector2 Origin)
+{
+    public Rotation(float value, Texture2D texture) : this(value, CenterOfTexture(texture)) { }
+
+    private static Vector2 CenterOfTexture(Texture2D texture)
+    {
+        return new Vector2((float) texture.Width / 2, (float) texture.Height / 2);
+    }
+}
 
 public readonly record struct Image(ImageId ImageId);

MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Content/Assets.cs

@@ -1,3 +1,4 @@
+
 using System;
 using Microsoft.Xna.Framework.Content;
 using Microsoft.Xna.Framework.Graphics;
@@ -13,8 +14,7 @@ public class Assets
         var allImageIds = Enum.GetValues<ImageId>();
         _images =
         [
-            // TODO: Auto-generate this initialization
+            content.Load<Texture2D>("Images/ball"),
-            content.Load<Texture2D>("Images/ball")
         ];
     }
 

MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/MonoGameBlank2dStartKitGame.cs

@@ -19,6 +19,8 @@ namespace MonoGameBlank2dStartKit.Core
     public class MonoGameBlank2dStartKitGame : Game
     {
         private TextureDrawSystem TextureDrawSystem { get; set; }
+        private VelocitySystem VelocitySystem { get; set; }
+        private RotationSystem RotationSystem { get; set; }
 
         // Resources for drawing.
         private readonly GraphicsDeviceManager graphicsDeviceManager;
@@ -90,7 +92,9 @@ namespace MonoGameBlank2dStartKit.Core
             _assets = new Assets(Content);
 
             TextureDrawSystem = new TextureDrawSystem(World, _assets, _spriteBatch);
-            Scenarios.Basic(World);
+            VelocitySystem = new VelocitySystem(World);
+            RotationSystem = new RotationSystem(World);
+            Scenarios.Basic(World, _assets);
             base.LoadContent();
         }
 
@@ -107,7 +111,9 @@ namespace MonoGameBlank2dStartKit.Core
                 || Keyboard.GetState().IsKeyDown(Keys.Escape))
                 Exit();
 
-            // TODO: Add your update logic here
+            var elapsedGameTime = gameTime.ElapsedGameTime;
+            VelocitySystem.Update(elapsedGameTime);
+            RotationSystem.Update(elapsedGameTime);
 
             base.Update(gameTime);
         }

MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Scenarios.cs

@@ -6,10 +6,13 @@ namespace MonoGameBlank2dStartKit.Core;
 
 public static class Scenarios
 {
-    public static void Basic(World world)
+    public static void Basic(World world, Assets assets)
     {
         var ball = world.CreateEntity();
         world.Set(ball, new Position(new Vector2(10, 10)));
         world.Set(ball, new Image(ImageId.Ball));
+        world.Set(ball, new Velocity(40f, 40f));
+        world.Set(ball, new Rotation(0, assets.GetTexture2D(ImageId.Ball)));
+        world.Set(ball, new RotationSpeed(3f, Drag: 0.03f));
     }
 }

MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Systems/RotationSystem.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Numerics;
+using MonoGameBlank2dStartKit.Core.Utils;
+using MoonTools.ECS;
+
+namespace MonoGameBlank2dStartKit.Core.Systems;
+
+public class RotationSystem : MoonTools.ECS.System
+{
+    private readonly Filter _filter;
+
+    public RotationSystem(World world) : base(world)
+    {
+        // Doesn't filter on Rotation, because it *should* blow up if RSpeed exists without Rotation.
+        _filter = FilterBuilder.Include<RotationSpeed>().Build();
+    }
+
+    public override void Update(TimeSpan delta)
+    {
+        foreach (var entity in _filter.Entities)
+        {
+            var currentRotation = World.Get<Rotation>(entity);
+            var rotationSpeed = World.Get<RotationSpeed>(entity);
+            float change = rotationSpeed.Speed * delta.SecFloat();
+            World.Set(entity, currentRotation with { Value = currentRotation.Value + change });
+
+            var newSpeed = rotationSpeed.Speed - (rotationSpeed.Drag * delta.SecFloat());
+            if (Math.Sign(newSpeed) != Math.Sign(rotationSpeed.Speed))
+            {
+                World.Remove<RotationSpeed>(entity);
+            }
+            else
+            {
+                World.Set(entity, rotationSpeed with
+                {
+                    Speed = newSpeed,
+                    Amount = rotationSpeed.Amount - change,
+                });
+            }
+        }
+    }
+}

MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Systems/TextureDrawSystem.cs

@@ -9,23 +9,33 @@ namespace MonoGameBlank2dStartKit.Core.Systems;
 public class TextureDrawSystem : MoonTools.ECS.System
 {
     private readonly Assets _assets;
-    private readonly Filter _filter;
     private readonly SpriteBatch _spriteBatch;
 
+    private readonly Filter _unrotatedFilter;
+    private readonly Filter _rotatedFilter;
+
     public TextureDrawSystem(World world, Assets assets, SpriteBatch spriteBatch) : base(world)
     {
         _assets = assets;
         _spriteBatch = spriteBatch;
-        _filter = FilterBuilder.Include<Image>().Include<Position>().Build();
+        _unrotatedFilter = FilterBuilder.Include<Image>().Include<Position>().Exclude<Rotation>().Build();
+        _rotatedFilter = FilterBuilder.Include<Image>().Include<Position>().Include<Rotation>().Build();
     }
 
     public override void Update(TimeSpan delta)
     {
-        foreach (var entity in _filter.Entities)
+        foreach (var entity in _unrotatedFilter.Entities)
         {
             var texture = _assets.GetTexture2D(World.Get<Image>(entity).ImageId);
             var position = World.Get<Position>(entity).Vector2;
             _spriteBatch.Draw(texture, position, Color.White);
         }
+        foreach (var entity in _rotatedFilter.Entities)
+        {
+            var texture = _assets.GetTexture2D(World.Get<Image>(entity).ImageId);
+            var position = World.Get<Position>(entity).Vector2;
+            var rotation = World.Get<Rotation>(entity);
+            _spriteBatch.Draw(texture, position, null, Color.White, rotation.Value, rotation.Origin, new Vector2(1, 1), SpriteEffects.None, 1);
+        }
     }
 }

MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Systems/VelocitySystem.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Numerics;
+using MonoGameBlank2dStartKit.Core.Utils;
+using MoonTools.ECS;
+
+namespace MonoGameBlank2dStartKit.Core.Systems;
+
+public class VelocitySystem : MoonTools.ECS.System
+{
+    private readonly Filter _filter;
+
+    public VelocitySystem(World world) : base(world)
+    {
+        _filter = FilterBuilder.Include<Position>().Include<Velocity>().Build();
+    }
+
+    public override void Update(TimeSpan delta)
+    {
+        float deltaSec = delta.SecFloat();
+        foreach (var entity in _filter.Entities)
+        {
+            var currentPosition = World.Get<Position>(entity).Vector2;
+            var velocity = World.Get<Velocity>(entity).Vector2;
+            World.Set(entity, new Position(
+                currentPosition.X + (velocity.X * deltaSec),
+                currentPosition.Y + (velocity.Y * deltaSec)
+            ));
+        }
+    }
+}

MonoGameBlank2dStartKit/MonoGameBlank2dStartKit.Core/Utils/TimeSpanExtensions.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace MonoGameBlank2dStartKit.Core.Utils;
+
+public static class TimeSpanExtensions
+{
+    public static float SecFloat(this TimeSpan span)
+    {
+        return (float)span.Ticks / TimeSpan.TicksPerSecond;
+    }
+}

generate-asset-class.js

@@ -0,0 +1,65 @@
+const fs = require('fs')
+
+const mgcbFile = process.argv[2]
+if (!mgcbFile) {
+    return 1
+}
+
+const fileContents = fs.readFileSync(mgcbFile, 'utf8')
+/** @type string[] */
+const lines = fileContents.split('\n')
+
+/** @type {Object.<string, string[]>} */
+const types = {}
+
+lines.forEach(line => {
+    const prefix = '#begin '
+    if (!line.startsWith(prefix)) {
+        return
+    }
+    line = line.substring(prefix.length)
+    const [type, name] = line.split('/')
+    types[type] ??= []
+    types[type].push(name)
+})
+
+let imageIdTextureLoads = ''
+let imageIdEnumString = ''
+
+types['Images'].forEach(image => {
+    const [name, ext] = image.split('.')
+    imageIdTextureLoads += '\n            '
+    imageIdTextureLoads += `content.Load<Texture2D>("Images/${name}"),`
+    
+    imageIdEnumString += '\n    '
+    imageIdEnumString += name[0].toUpperCase() + name.substring(1)
+})
+
+console.log(`
+using System;
+using Microsoft.Xna.Framework.Content;
+using Microsoft.Xna.Framework.Graphics;
+
+namespace MonoGameBlank2dStartKit.Core.Content;
+
+public class Assets
+{
+    private readonly Texture2D[] _images;
+
+    public Assets(ContentManager content)
+    {
+        var allImageIds = Enum.GetValues<ImageId>();
+        _images =
+        [${imageIdTextureLoads}
+        ];
+    }
+
+    public Texture2D GetTexture2D(ImageId imageId)
+    {
+        return _images[(int)imageId];
+    }
+}
+
+public enum ImageId
+{${imageIdEnumString}
+}`)