From e4b4e473273e13e9ec3084c38059e0755e007cd3 Mon Sep 17 00:00:00 2001
From: Evan Hemsley <evan@moonside.games>
Date: Thu, 13 Jun 2019 22:15:15 -0700
Subject: [PATCH] changing everything to structs

---
 src/Component.cs        |  2 +-
 src/ComponentManager.cs | 38 +++++++++++++++++---------------------
 src/Entity.cs           | 12 ++++++------
 test/EntityTest.cs      | 38 +++++++++++++++++++++++++++++---------
 4 files changed, 53 insertions(+), 37 deletions(-)

diff --git a/src/Component.cs b/src/Component.cs
index d0660f8..2f7ee8c 100644
--- a/src/Component.cs
+++ b/src/Component.cs
@@ -1,4 +1,4 @@
 namespace Encompass
 {
-    public abstract class Component {}
+    public interface IComponent {}
 }
diff --git a/src/ComponentManager.cs b/src/ComponentManager.cs
index 06be097..1153aaa 100644
--- a/src/ComponentManager.cs
+++ b/src/ComponentManager.cs
@@ -4,49 +4,45 @@ using System.Linq;
 
 namespace Encompass {
     internal class ComponentManager {
-        private Dictionary<uint, List<Component>> entityIDToComponents = new Dictionary<uint, List<Component>>();
+        private Dictionary<uint, List<IComponent>> entityIDToComponents = new Dictionary<uint, List<IComponent>>();
 
-        private Dictionary<Type, List<Component>> activeComponents = new Dictionary<Type, List<Component>>();
-        private Dictionary<Type, List<Component>> inactiveComponents = new Dictionary<Type, List<Component>>();
+        private Dictionary<Type, List<IComponent>> activeComponents = new Dictionary<Type, List<IComponent>>();
+        private Dictionary<Type, List<IComponent>> inactiveComponents = new Dictionary<Type, List<IComponent>>();
 
-        private List<Component> componentsToActivate = new List<Component>();
-        private List<Component> componentsToDeactivate = new List<Component>();
-        private List<Component> componentsToRemove = new List<Component>();
-
-        internal TComponent CreateComponent<TComponent>(uint entityID) where TComponent : Component, new() {
-            var component = new TComponent();
+        private List<IComponent> componentsToActivate = new List<IComponent>();
+        private List<IComponent> componentsToDeactivate = new List<IComponent>();
+        private List<IComponent> componentsToRemove = new List<IComponent>();
 
+        internal void AddComponent<TComponent>(uint entityID, TComponent component) where TComponent : struct, IComponent {
             if (!entityIDToComponents.ContainsKey(entityID)) {
-                entityIDToComponents.Add(entityID, new List<Component>());
+                entityIDToComponents.Add(entityID, new List<IComponent>());
             }
 
             entityIDToComponents[entityID].Add(component);
 
             if (!activeComponents.ContainsKey(typeof(TComponent))) {
-                activeComponents.Add(typeof(TComponent), new List<Component>());
-                inactiveComponents.Add(typeof(TComponent), new List<Component>());
+                activeComponents.Add(typeof(TComponent), new List<IComponent>());
+                inactiveComponents.Add(typeof(TComponent), new List<IComponent>());
             }
 
             MarkForActivation(component);
-
-            return component;
         }
 
-        internal IEnumerable<Component> GetComponentsByEntity(uint entityID) {
+        internal IEnumerable<IComponent> GetComponentsByEntity(uint entityID) {
             return entityIDToComponents[entityID];
         }
 
-        internal IEnumerable<TComponent> GetActiveComponentsByType<TComponent>() where TComponent : Component {
+        internal IEnumerable<TComponent> GetActiveComponentsByType<TComponent>() where TComponent : struct, IComponent {
             return activeComponents[typeof(TComponent)].Cast<TComponent>();
         }
 
-        internal IEnumerable<TComponent> GetComponentsByEntityAndType<TComponent>(uint entityID) where TComponent : Component {
-            var entity_components = GetComponentsByEntity(entityID);
+        internal IEnumerable<TComponent> GetComponentsByEntityAndType<TComponent>(uint entityID) where TComponent : struct, IComponent {
+            var entity_components = GetComponentsByEntity(entityID).Cast<TComponent>();
             var active_components_by_type = GetActiveComponentsByType<TComponent>();
             return entity_components.Intersect(active_components_by_type).Cast<TComponent>();
         }
 
-        internal bool EntityHasComponentOfType<TComponent>(uint entityID) where TComponent : Component {
+        internal bool EntityHasComponentOfType<TComponent>(uint entityID) where TComponent : struct, IComponent {
             return GetComponentsByEntityAndType<TComponent>(entityID).Any();
         }
 
@@ -61,11 +57,11 @@ namespace Encompass {
             entityIDToComponents.Remove(entityID);
         }
 
-        internal void MarkForActivation(Component component) {
+        internal void MarkForActivation(IComponent component) {
             componentsToActivate.Add(component);
         }
 
-        internal void MarkForRemoval(Component component) {
+        internal void MarkForRemoval(IComponent component) {
             componentsToRemove.Add(component);
         }
 
diff --git a/src/Entity.cs b/src/Entity.cs
index 9b76c5f..abdf8ba 100644
--- a/src/Entity.cs
+++ b/src/Entity.cs
@@ -4,7 +4,7 @@ using System.Linq;
 
 namespace Encompass
 {
-    public class Entity
+    public struct Entity
     {
         public readonly uint id;
 
@@ -15,19 +15,19 @@ namespace Encompass
             this.componentManager = componentManager;
         }
 
-        public TComponent AddComponent<TComponent>() where TComponent : Component, new() {
-            return componentManager.CreateComponent<TComponent>(id);
+        public void AddComponent<TComponent>(TComponent component) where TComponent : struct, IComponent {
+            componentManager.AddComponent<TComponent>(id, component);
         }
 
-        public IEnumerable<TComponent> GetComponents<TComponent>() where TComponent : Component {
+        public IEnumerable<TComponent> GetComponents<TComponent>() where TComponent : struct, IComponent {
             return componentManager.GetComponentsByEntityAndType<TComponent>(id);
         }
 
-        public TComponent GetComponent<TComponent>() where TComponent : Component {
+        public TComponent GetComponent<TComponent>() where TComponent : struct, IComponent {
             return GetComponents<TComponent>().First();
         }
 
-        public bool HasComponent<TComponent>() where TComponent : Component {
+        public bool HasComponent<TComponent>() where TComponent : struct, IComponent {
             return componentManager.EntityHasComponentOfType<TComponent>(id);
         }
 
diff --git a/test/EntityTest.cs b/test/EntityTest.cs
index 230e11c..dba42e2 100644
--- a/test/EntityTest.cs
+++ b/test/EntityTest.cs
@@ -4,7 +4,7 @@ using System.Linq;
 namespace Encompass
 {
     namespace Tests {
-        class MockComponent : Component {
+        struct MockComponent : IComponent {
             public string myString;
             public int myInt;
         }
@@ -17,9 +17,11 @@ namespace Encompass
                 var world = new World();
                 var entity = world.CreateEntity();
 
-                var mockComponent = entity.AddComponent<MockComponent>();
-                mockComponent.myString = "hello";
+                MockComponent mockComponent;
                 mockComponent.myInt = 3;
+                mockComponent.myString = "hello";
+
+                entity.AddComponent<MockComponent>(mockComponent);
 
                 world.Update();
 
@@ -33,9 +35,21 @@ namespace Encompass
                 var world = new World();
                 var entity = world.CreateEntity();
 
-                var mockComponentA = entity.AddComponent<MockComponent>();
-                var mockComponentB = entity.AddComponent<MockComponent>();
-                var mockComponentC = entity.AddComponent<MockComponent>();
+                MockComponent mockComponentA;
+                mockComponentA.myInt = 3;
+                mockComponentA.myString = "hello";
+
+                MockComponent mockComponentB;
+                mockComponentB.myInt = 5;
+                mockComponentB.myString = "wassup";
+
+                MockComponent mockComponentC;
+                mockComponentC.myInt = 1;
+                mockComponentC.myString = "howdy";
+
+                entity.AddComponent<MockComponent>(mockComponentA);
+                entity.AddComponent<MockComponent>(mockComponentB);
+                entity.AddComponent<MockComponent>(mockComponentC);
 
                 world.Update();
 
@@ -50,9 +64,11 @@ namespace Encompass
                 var world = new World();
                 var entity = world.CreateEntity();
 
-                var mockComponent = entity.AddComponent<MockComponent>();
-                mockComponent.myString = "hello";
+                MockComponent mockComponent;
                 mockComponent.myInt = 3;
+                mockComponent.myString = "hello";
+
+                entity.AddComponent<MockComponent>(mockComponent);
 
                 world.Update();
 
@@ -65,7 +81,11 @@ namespace Encompass
                 var world = new World();
                 var entity = world.CreateEntity();
 
-                var mockComponent = entity.AddComponent<MockComponent>();
+                MockComponent mockComponent;
+                mockComponent.myInt = 3;
+                mockComponent.myString = "hello";
+
+                entity.AddComponent<MockComponent>(mockComponent);
 
                 world.Update();