initial engine

src/ComponentManager.cs

@@ -36,6 +36,10 @@ namespace Encompass {
             return activeComponents[typeof(TComponent)].Cast<TComponent>();
         }
 
+        internal TComponent GetActiveComponentByType<TComponent>() where TComponent : struct, IComponent {
+            return GetActiveComponentsByType<TComponent>().Single();
+        }
+
         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>();

src/Engine.cs

@@ -0,0 +1,30 @@
+using System.Collections.Generic;
+
+namespace Encompass {
+    public abstract class Engine {
+        private EntityManager entityManager;
+        private ComponentManager componentManager;
+
+        internal void AssignEntityManager(EntityManager entityManager) {
+            this.entityManager = entityManager;
+        }
+
+        internal void AssignComponentManager(ComponentManager componentManager) {
+            this.componentManager = componentManager;
+        }
+
+        public abstract void Update(float dt);
+
+        protected Entity CreateEntity() {
+            return this.entityManager.CreateEntity();
+        }
+
+        protected IEnumerable<TComponent> ReadComponents<TComponent>() where TComponent : struct, IComponent {
+            return this.componentManager.GetActiveComponentsByType<TComponent>();
+        }
+
+        protected TComponent ReadComponent<TComponent>() where TComponent : struct, IComponent {
+            return this.componentManager.GetActiveComponentByType<TComponent>();
+        }
+    }
+}

src/Entity.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Linq;
 
 namespace Encompass

src/EntityManager.cs

@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using System.Linq;
 
 namespace Encompass {
     internal class EntityManager {

src/World.cs

@@ -1,22 +1,29 @@
+using System.Collections.Generic;
+
 namespace Encompass {
     public class World {
-        EntityManager entityManager;
-        ComponentManager componentManager;
+        private List<Engine> engines;
+        private EntityManager entityManager;
+        private ComponentManager componentManager;
 
-        internal World(EntityManager entityManager, ComponentManager componentManager) {
+        internal World(
+            List<Engine> engines,
+            EntityManager entityManager,
+            ComponentManager componentManager
+        ) {
+            this.engines = engines;
             this.entityManager = entityManager;
             this.componentManager = componentManager;
         }
 
-        public void Update() {
+        public void Update(float dt) {
+            foreach (var engine in engines) {
+                engine.Update(dt);
+            }
+
             entityManager.DestroyMarkedEntities();
             componentManager.ActivateComponents();
             componentManager.RemoveComponents();
-
-        }
-
-        public Entity CreateEntity() {
-            return entityManager.CreateEntity();
         }
     }
 }

src/WorldBuilder.cs

@@ -2,6 +2,8 @@ using System.Collections.Generic;
 
 namespace Encompass {
     public class WorldBuilder {
+        private List<Engine> engines = new List<Engine>();
+
         private ComponentManager componentManager;
         private EntityManager entityManager;
 
@@ -14,8 +16,23 @@ namespace Encompass {
             return this.entityManager.CreateEntity();
         }
 
+        public Engine AddEngine<TEngine>() where TEngine : Engine, new() {
+            var engine = new TEngine();
+
+            engine.AssignEntityManager(this.entityManager);
+            engine.AssignComponentManager(this.componentManager);
+
+            engines.Add(engine);
+
+            return engine;
+        }
+
         public World Build() {
-            var world = new World(this.entityManager, this.componentManager);
+            var world = new World(
+                this.engines,
+                this.entityManager,
+                this.componentManager
+            );
 
             this.componentManager.ActivateComponents();
             this.componentManager.RemoveComponents();

src/encompass-cs.csproj

@@ -12,5 +12,6 @@
     <Content Include="EntityManager.cs" />
     <Content Include="ComponentManager.cs" />
     <Content Include="WorldBuilder.cs" />
+    <Content Include="Engine.cs" />
   </ItemGroup>
 </Project>

test/EngineTest.cs

@@ -0,0 +1,47 @@
+using NUnit.Framework;
+using System.Linq;
+
+using Encompass;
+using System.Collections.Generic;
+
+namespace Tests {
+    public class EngineTest
+    {
+        static IEnumerable<MockComponent> components;
+
+        public class TestEngine : Engine
+        {
+            public override void Update(float dt)
+            {
+                components = this.ReadComponents<MockComponent>();
+            }
+        }
+
+        [Test]
+        public void ReadComponents()
+        {
+            var worldBuilder = new WorldBuilder();
+            worldBuilder.AddEngine<TestEngine>();
+
+            var entity = worldBuilder.CreateEntity();
+
+            MockComponent mockComponent;
+            mockComponent.myInt = 0;
+            mockComponent.myString = "hello";
+
+            MockComponent mockComponentB;
+            mockComponentB.myInt = 1;
+            mockComponentB.myString = "howdy";
+
+            entity.AddComponent(mockComponent);
+            entity.AddComponent(mockComponentB);
+
+            var world = worldBuilder.Build();
+
+            world.Update(0.01f);
+
+            Assert.Contains(mockComponent, components.ToList());
+            Assert.Contains(mockComponentB, components.ToList());
+        }
+    }
+}

test/test.csproj

@@ -1,16 +1,17 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project Sdk="Microsoft.NET.Sdk">
-  <PropertyGroup>
-    <TargetFramework>netcoreapp2.2</TargetFramework>
-    <IsPackable>false</IsPackable>
-  </PropertyGroup>
-  <ItemGroup>
-    <PackageReference Include="nunit" Version="3.11.0" />
-    <PackageReference Include="NUnit3TestAdapter" Version="3.11.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
-    <Content Include="EntityTest.cs" />
-  </ItemGroup>
-  <ItemGroup>
-    <ProjectReference Include="..\src\encompass-cs.csproj" />
-  </ItemGroup>
-</Project>
+<?xml version="1.0" encoding="utf-8"?>
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>netcoreapp2.2</TargetFramework>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="nunit" Version="3.11.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="3.11.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
+    <Content Include="EntityTest.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\src\encompass-cs.csproj" />
+    <Content Include="EngineTest.cs" />
+  </ItemGroup>
+</Project>