Added Entity hierarchy and hierarchical transforms

GlitchyEngine/src/Renderer/Renderer.bf

@@ -72,7 +72,7 @@ namespace GlitchyEngine.Renderer
 			var camera = world.GetComponent<CameraComponent>(cameraEntity);
 			var transform = world.GetComponent<TransformComponent>(cameraEntity);
 
-			var trans = transform.Transform;
+			var trans = transform.WorldTransform;
 			var view = trans.Invert();
 			var proj = camera.Projection;
 

GlitchyEngine/src/World/EcsWorld.bf

@@ -221,8 +221,9 @@ namespace GlitchyEngine.World
 			Entity entity = world.NewEntity();
 
 			TransformComponent* myComp = world.AssignComponent<TransformComponent>(entity);
-			myComp.Transform = Matrix.Identity;
+			myComp.LocalTransform = Matrix.Identity;
 
+			#unwarn
 			TransformComponent gotComp = *world.GetComponent<TransformComponent>(entity);
 
 			world.RemoveComponent<TransformComponent>(entity);

GlitchyEngine/src/World/ParentComponent.bf

@@ -0,0 +1,10 @@
+namespace GlitchyEngine.World
+{
+	/**
+	 * A Component that allows to specify a parent entity.
+	 */
+	public struct ParentComponent
+	{
+		public Entity Entity;
+	}
+}

GlitchyEngine/src/World/TransformComponent.bf

@@ -8,17 +8,20 @@ namespace GlitchyEngine.World
 		Vector3 _rotation = .Zero;
 		Vector3 _scale = .One;
 
-		Matrix _transform;
-		bool _dirty;
+		Matrix _localTransform;
+		public bool IsDirty;
 
-		public Matrix Transform
+		public Matrix WorldTransform;
+
+		/// The frame when the transform was recalculated
+		public uint Frame;
+
+		public Matrix LocalTransform
 		{
-			get mut
-			{
-				return _transform;
-			}
-			set mut => _transform = value;
+			get => _localTransform;
+			set mut => _localTransform = value;
 		}
+
 		public Vector3 Position
 		{
 			get => _position;
@@ -28,7 +31,7 @@ namespace GlitchyEngine.World
 					return;
 
 				_position = value;
-				_dirty = true;
+				IsDirty = true;
 			}
 		}
 
@@ -41,7 +44,7 @@ namespace GlitchyEngine.World
 					return;
 
 				_rotation = value;
-				_dirty = true;
+				IsDirty = true;
 			}
 		}
 
@@ -54,17 +57,8 @@ namespace GlitchyEngine.World
 					return;
 
 				_scale = value;
-				_dirty = true;
+				IsDirty = true;
 			}
 		}
-
-		public void Update() mut
-		{
-			if(!_dirty)
-				return;
-			_transform = .Translation(_position) * .RotationX(_rotation.X) *
-				.RotationY(_rotation.Y) * .RotationZ(_rotation.Z) * .Scaling(_scale);
-			_dirty = false;
-		}
 	}
 }

GlitchyEngine/src/World/TransformSystem.bf

@@ -0,0 +1,57 @@
+namespace GlitchyEngine.World
+{
+	public static class TransformSystem
+	{
+		static uint _frame;
+
+		public static void Update(EcsWorld world)
+		{
+			_frame++;
+
+			for(var entity in world.Enumerate(typeof(TransformComponent)))
+			{
+				UpdateEntity(entity, world);
+			}
+		}
+
+		private static TransformComponent* UpdateEntity(Entity entity, EcsWorld world)
+		{
+			// Todo: this probably needs a rewrite as it may scale poorly with deep hierarchies!
+
+			var transform = world.GetComponent<TransformComponent>(entity);
+
+			// If tranform was updated this frame -> skip
+			if(transform.Frame == _frame)
+				return transform;
+
+			var parent = world.GetComponent<ParentComponent>(entity);
+
+			if(transform.IsDirty)
+			{
+				transform.LocalTransform = .Translation(transform.Position) * .RotationX(transform.Rotation.X) *
+					.RotationY(transform.Rotation.Y) * .RotationZ(transform.Rotation.Z) * .Scaling(transform.Scale);
+				transform.Frame = _frame;
+				transform.IsDirty = false;
+
+				if(parent == null)
+				{
+					transform.WorldTransform = transform.LocalTransform;
+				}
+			}
+
+			if(parent != null)
+			{
+				var parentTransform = UpdateEntity(parent.Entity, world);
+
+				// Parent transform is newer than our transform or was updated this frame
+				if(parentTransform.Frame >= transform.Frame)
+				{
+					transform.WorldTransform = parentTransform.WorldTransform * transform.LocalTransform;
+					transform.Frame = parentTransform.Frame;
+				}
+			}
+
+			return transform;
+		}
+	}
+}