Naming, comments and local to world update

Nerfed.Editor/Program.cs

@@ -1,5 +1,6 @@
 using MoonTools.ECS;
 using Nerfed.Runtime;
+using Nerfed.Runtime.Components;
 using Nerfed.Runtime.Systems;
 using System.Numerics;
 
@@ -23,7 +24,7 @@ private static void Main(string[] args)
     private static void HandleOnInitialize()
     {
         systems.Add(new ParentSystem(world));
-        systems.Add(new TransformSystem(world));
+        systems.Add(new LocalToWorldSystem(world));
 
         Entity ent1 = world.CreateEntity();
         world.Set(ent1, new LocalTransform(new Vector3(1, 0, 0), Quaternion.Identity, Vector3.One));

Nerfed.Runtime/Systems/LocalToWorldSystem.cs

@@ -3,13 +3,21 @@
 using Nerfed.Runtime.Util;
 using System.Numerics;
 
+// TODO:
+// Explore if having a WorldTransform and LocalTransfom component each holding position, rotation, scale values and the matricies is useful.
+// Often you need to either get or set these values.
+// If so, we probably need a utility funciton to do so. Since changing these values means that we need to update all the related data + children as well.
+
+// TODO:
+// When modifying transform all the children need to be updated as well.
+
 namespace Nerfed.Runtime.Systems
 {
-    public class TransformSystem : MoonTools.ECS.System
+    public class LocalToWorldSystem : MoonTools.ECS.System
     {
         private readonly Filter rootEntitiesFilter;
 
-        public TransformSystem(World world) : base(world)
+        public LocalToWorldSystem(World world) : base(world)
         {
             rootEntitiesFilter = FilterBuilder.Include<LocalTransform>().Exclude<Parent>().Build();
         }
@@ -27,8 +35,8 @@ public override void Update(TimeSpan delta)
         private void UpdateWorldTransform(in Entity entity, in Matrix4x4 parentLocalToWorld)
         {
             // TODO: Only update dirty transforms.
-            // Maybe store the local transform matrix.
+            // If a parent is dirty all the children need to update their localToWorld matrix.
-            // If something is dirty all the children need to update their localToWorld matrix.
+            // How do we check if something is dirty? How do we know if a LocalTransform has been changed?
 
             LocalTransform localTransform = Get<LocalTransform>(entity);
             Matrix4x4 localToWorldMatrix = Matrix4x4.Multiply(parentLocalToWorld, localTransform.TRS());

Nerfed.Runtime/Util/Transform.cs

@@ -1,4 +1,6 @@
-using Nerfed.Runtime.Components;
+using MoonTools.ECS;
+using Nerfed.Runtime.Components;
+using System.Collections.Generic;
 using System.Numerics;
 
 namespace Nerfed.Runtime.Util
@@ -21,5 +23,36 @@ public static Matrix4x4 TRS(in this LocalTransform localTransform)
                 Matrix4x4.CreateFromQuaternion(localTransform.rotation) *
                 Matrix4x4.CreateTranslation(localTransform.position);
         }
+
+        // Force update the transform data of an entity (and children).
+        // Useful for when you need precise up to date transform data.
+        public static void ForceUpdateLocalToWorld(in World world, in Entity entity)
+        {
+            Matrix4x4 parentLocalToWorldMatrix = Matrix4x4.Identity;
+
+            if (world.Has<Parent>(entity))
+            {
+                Entity parent = world.Get<Parent>(entity).parentEntity;
+                parentLocalToWorldMatrix = world.Get<LocalToWorld>(parent).localToWorldMatrix;
+            }
+
+            ForceUpdateLocalToWorld(world, entity, parentLocalToWorldMatrix);
+        }
+
+        private static void ForceUpdateLocalToWorld(in World world, in Entity entity, in Matrix4x4 parentLocalToWorldMatrix)
+        {
+            LocalTransform localTransform = world.Get<LocalTransform>(entity);
+            Matrix4x4 localToWorldMatrix = Matrix4x4.Multiply(parentLocalToWorldMatrix, localTransform.TRS());
+            LocalToWorld localToWorld = new(localToWorldMatrix);
+            world.Set(entity, localToWorld);
+
+            Log.Info($"Entity {entity} | local position {localTransform.position} | world position {localToWorldMatrix.Translation}");
+
+            ReverseSpanEnumerator<Entity> childEntities = world.OutRelations<ChildRelation>(entity);
+            foreach (Entity childEntity in childEntities)
+            {
+                ForceUpdateLocalToWorld(world, childEntity, parentLocalToWorldMatrix);
+            }
+        }
     }
 }