Improving ECS and adding documentation.

10 files changed, 101 insertions, 37 deletions

diff --git a/yage/entity/README.md b/yage/entity/README.md
new file mode 100644
index 00000000..ebf539f3
--- /dev/null
+++ b/yage/entity/README.md
@@ -0,0 +1,36 @@
+# Entity Component System (ECS)
+
+## Structure
+
+### Entity
+
+The `EntityManager` is the class that manages the entities, by allocating and
+deleting them as necessary. The `Entity` itself is just a handle, and does not
+contain any logic or data. It is just used to refer to the `Entity` when doing
+operations on it.
+
+### Components
+
+These are just data that is associated with Entities, and it gets processed
+by the Systems when these are updated. The systems only process a few components
+at once, which separates the logic and makes it easy to develop the Systems and
+Components orthogonally. 
+
+### Systems
+
+These process the Components and update their state. This completely separates
+the data from the logic, and means that they can be tested independently. New
+systems can be created by inheriting from the `BaseSystem`, which provides an
+interface which then enables that system to be added to the main `Engine`
+through different types of `Spaces`.
+
+## Implementation
+
+The Entity is just an `unsigned int`, which has a `typedef` called `Entity`,
+which is also what all the functions return. 
+
+The link between the components are managed by a templated `ComponentMapper`
+class, that links every entity with it's component. This way it is also to find
+out if an entity is part of a specific component, and that entity will never be
+processed in the system that only targets that component, which makes it much
+more efficient.
diff --git a/yage/entity/componentmanager.h b/yage/entity/componentmanager.h
new file mode 100644
index 00000000..fa1096e7
--- /dev/null
+++ b/yage/entity/componentmanager.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include <map>
+
+#include "entitymanager.h"
+
+namespace yage
+{
+
+template <typename CompT>
+class ComponentMapper
+{
+private:
+    std::map<Entity, CompT> map_;
+};
+
+} // namespace yage
diff --git a/yage/entity/engine.cpp b/yage/entity/engine.cpp
index 503dc919..f3a056db 100644
--- a/yage/entity/engine.cpp
+++ b/yage/entity/engine.cpp
@@ -8,20 +8,28 @@
 
 #include "engine.h"
 
+#include "../core/core.h"
+
 #include "space.h"
-#include "entity.h"
 
 namespace yage
 {
 
+Engine::~Engine()
+{
+    quit();
+}
+
 void Engine::init()
 {
+    yage::init();
     window_.create("Game Engine", 800, 640);
 }
 
 void Engine::mainLoop()
 {
     while (!window_.shouldClose()) {
+        window_.pollEvents();
         window_.clearBuffer();
 
         update();
@@ -32,8 +40,8 @@ void Engine::mainLoop()
 
 void Engine::update()
 {
-    for(auto &space : spaces_) {
-        
+    for (auto &space : spaces_) {
+        space->update();
     }
 }
 
diff --git a/yage/entity/engine.h b/yage/entity/engine.h
index fe7e5eb0..bac32fe0 100644
--- a/yage/entity/engine.h
+++ b/yage/entity/engine.h
@@ -6,11 +6,12 @@
  * ----------------------------------------------------------------------------
  */
 
-#ifndef YAGE_CORE_ENGINE_H
-#define YAGE_CORE_ENGINE_H
+#pragma once
 
 #include "system.h"
+
 #include "../core/window.h"
+#include "../util/noncopyable.h"
 
 #include <memory>
 #include <vector>
@@ -24,9 +25,12 @@ class Space;
  * Main engine class that contains a systems, the main loop and the update
  * function that updates all the systems.
  */
-class Engine
+class Engine : public NonCopyable
 {
 public:
+
+    ~Engine();
+
     /// Initialize window and other aspects of the engine.
     void init();
 
@@ -41,7 +45,7 @@ public:
 
     /// Returns the instance of the engine, as there is only one instance of the
     /// engine.
-    static Engine &instance();
+    static Engine& instance();
 
 private:
     /// Window
@@ -52,5 +56,3 @@ private:
 };
 
 } // namespace yage
-
-#endif
diff --git a/yage/entity/entity.h b/yage/entity/entity.h
deleted file mode 100644
index 9ba0d46d..00000000
--- a/yage/entity/entity.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/** ---------------------------------------------------------------------------
- * @file: entity.h
- *
- * Copyright (c) 2017 Yann Herklotz Grave <ymherklotz@gmail.com>
- * MIT License, see LICENSE file for more details.
- * ----------------------------------------------------------------------------
- */
-
-#ifndef YAGE_ENGINE_ENTITY_H
-#define YAGE_ENGINE_ENTITY_H
-
-#include <vector>
-
-namespace yage
-{
-
-typedef unsigned int Entity;
-
-} // namespace yage
-
-#endif
diff --git a/yage/entity/entitymanager.cpp b/yage/entity/entitymanager.cpp
index 5eb17075..205eec30 100644
--- a/yage/entity/entitymanager.cpp
+++ b/yage/entity/entitymanager.cpp
@@ -13,8 +13,7 @@ namespace yage
 
 EntityManager::EntityManager(Space *space) : space_(space) {}
 
-EntityManager::EntityManager(Space *space, std::size_t n)
-    : space_(space)
+EntityManager::EntityManager(Space *space, std::size_t n) : space_(space)
 {
     entities_.reserve(n);
 }
diff --git a/yage/entity/entitymanager.h b/yage/entity/entitymanager.h
index 85ad9051..2de5e13c 100644
--- a/yage/entity/entitymanager.h
+++ b/yage/entity/entitymanager.h
@@ -9,8 +9,6 @@
 #ifndef YAGE_ENGINE_ENTITYMANAGER_H
 #define YAGE_ENGINE_ENTITYMANAGER_H
 
-#include "entity.h"
-
 #include <vector>
 
 namespace yage
@@ -18,6 +16,8 @@ namespace yage
 
 class Space;
 
+typedef unsigned int Entity;
+
 /**
  * Manages entities in a space.
  */
@@ -51,7 +51,12 @@ public:
      *
      * @return The handle to the entity that was created in the space.
      */
-    unsigned createEntity();
+    Entity createEntity();
+
+    /**
+     * Delete an entity.
+     */
+    void deleteEntity(Entity entity);
 
 private:
     /**
diff --git a/yage/entity/space.cpp b/yage/entity/space.cpp
index f3e343b5..24afda72 100644
--- a/yage/entity/space.cpp
+++ b/yage/entity/space.cpp
@@ -18,4 +18,11 @@ unsigned Space::createEntity()
     return em_.createEntity();
 }
 
+void Space::update()
+{
+    for (auto &system : systems_) {
+        system->update();
+    }
+}
+
 } // namespace yage
diff --git a/yage/entity/space.h b/yage/entity/space.h
index 969ef503..113110aa 100644
--- a/yage/entity/space.h
+++ b/yage/entity/space.h
@@ -42,7 +42,12 @@ public:
      * visible to the user, as the user only needs to worry about the
      * handle when referring to the Entity and changing it.
      */
-    unsigned createEntity();
+    Entity createEntity();
+
+    /**
+     * Update all the systems.
+     */
+    void update();
 
 private:
     /**
@@ -58,6 +63,11 @@ private:
      * current space.
      */
     EntityManager em_;
+
+    /**
+     * Manages all the components
+     */
+    // ComponentManager cm_;
 };
 
 } // namespace yage
diff --git a/yage/entity/system.h b/yage/entity/system.h
index 15845390..0ca50009 100644
--- a/yage/entity/system.h
+++ b/yage/entity/system.h
@@ -19,7 +19,8 @@ namespace yage
 class System : public NonCopyable
 {
 public:
-    
+    virtual void init() = 0;
+    virtual void update() = 0;
 };
 
 } // namespace yage