From aaf7c1662abb78228b774f728061b092e4467b07 Mon Sep 17 00:00:00 2001
From: Yann Herklotz <ymherklotz@gmail.com>
Date: Wed, 20 Jun 2018 23:20:05 +0100
Subject: Adding entity implementation and changing API

---
 yage/entity/entity.cpp | 40 ++++++++++++++++++++++++++++++++++++++++
 yage/entity/entity.h   | 14 +++++++++++---
 2 files changed, 51 insertions(+), 3 deletions(-)
 create mode 100644 yage/entity/entity.cpp

diff --git a/yage/entity/entity.cpp b/yage/entity/entity.cpp
new file mode 100644
index 00000000..050514c3
--- /dev/null
+++ b/yage/entity/entity.cpp
@@ -0,0 +1,40 @@
+#include "entity.h"
+
+#include <algorithm>
+
+namespace yage
+{
+
+Entity EntityManager::create_entity()
+{
+    Entity entity = update_next_entity();
+    component_masks_.push_back(ComponentMask(0));
+    return entity;
+}
+
+EntityManager &EntityManager::delete_entity(Entity entity)
+{
+    deleted_.push_back(entity);
+    return *this;
+}
+
+bool EntityManager::is_valid(Entity entity) const
+{
+    auto it = std::find(deleted_.begin(), deleted_.end(), entity);
+    if (it == deleted_.end()) {
+        return true;
+    }
+    return false;
+}
+
+Entity EntityManager::update_next_entity()
+{
+    if (deleted_.empty()) {
+        return ++next_entity_;
+    }
+    next_entity_ = deleted_.back();
+    deleted_.pop_back();
+    return next_entity_;
+}
+
+} // namespace yage
diff --git a/yage/entity/entity.h b/yage/entity/entity.h
index 01a47f5c..d9a221b9 100644
--- a/yage/entity/entity.h
+++ b/yage/entity/entity.h
@@ -1,6 +1,8 @@
 #include <bitset>
 #include <vector>
 
+namespace yage {
+
 /** 
  * The entity is currently just an unsigned integer, which may change to a
  * class in the future.
@@ -38,13 +40,19 @@ class ComponentGroup;
 class EntityManager
 {
 public:
-    Entity createEntity();
-    EntityManager &deleteEntity(Entity entity);
-    void addComponent(Entity entity, BaseComponent *component);
+    Entity create_entity();
+    EntityManager &delete_entity(Entity entity);
+    bool is_valid(Entity entity) const;
+    void add_component(Entity entity, BaseComponent *component);
 
 private:
+    Entity update_next_entity();
+
     Entity next_entity_;
 
     std::vector<BaseComponentGroup *> component_group_;
     std::vector<ComponentMask> component_masks_;
+    std::vector<Entity> deleted_;
 };
+
+} // namespace yage
-- 
cgit