From 3f39e271742341f7d4aca04497ca55842981ca6e Mon Sep 17 00:00:00 2001
From: SeanOMik <seanomik@gmail.com>
Date: Fri, 16 Sep 2022 11:50:33 -0400
Subject: [PATCH] Add simple EntityManager for updating entities

---
 examples/dev_testing/src/main.cpp     | 21 ++++++--------
 include/simpleengine/ecs/entity.h     |  3 ++
 include/simpleengine/entity_manager.h | 25 +++++++++++++++++
 src/entity_manager.cpp                | 40 +++++++++++++++++++++++++++
 4 files changed, 77 insertions(+), 12 deletions(-)
 create mode 100644 include/simpleengine/entity_manager.h
 create mode 100644 src/entity_manager.cpp

diff --git a/examples/dev_testing/src/main.cpp b/examples/dev_testing/src/main.cpp
index 93b5150..c3ab15d 100644
--- a/examples/dev_testing/src/main.cpp
+++ b/examples/dev_testing/src/main.cpp
@@ -1,6 +1,7 @@
 #include "simpleengine/camera.h"
 #include "simpleengine/ecs/component/model_componenet.h"
 #include "simpleengine/ecs/entity.h"
+#include "simpleengine/entity_manager.h"
 #include "simpleengine/gfx/light.h"
 #include "simpleengine/gfx/material.h"
 #include "simpleengine/gfx/model.h"
@@ -169,30 +170,26 @@ int main(int argc, char *argv[]) {
 
     se::gfx::Material material(white_texture, 1.f, 0.f, 0.f, 0.f, 0.f);
 
-    auto entity = std::make_shared<simpleengine::Entity>();
+    // Create a model component
     se::gfx::Model model(cube_vertices, cube_indicies, std::optional<se::gfx::Material>(material));
     model.calculate_normals();
-
     se::ModelComponent model_component(model);
 
+    // Create the entity and add the model component to it.
+    auto entity = std::make_shared<simpleengine::Entity>();
     entity->add_component(model_component);
     entity->translate(3.5f, 0.f, 0.f);
 
-    /* auto cube = std::make_shared<se::gfx::Model>(cube_vertices, cube_indicies,
-        std::optional<se::gfx::Material>(material));
-    cube->calculate_normals();
-    cube->translate(3.5f, 0.f, 0.f); */
-    //game.add_event(cube);
-
+    // Create a renderer and submit the entity into it.
     auto renderer  = std::make_shared<se::gfx::Renderer>(game.get_window(), core_shader);
     renderer->enable_debug();
     renderer->submit_entity(entity);
     game.add_renderable(renderer);
-    /* renderer->add_model(white_texture, cube);
-    game.add_event(renderer); */
 
-    /* auto r_event = std::make_shared<RendererEvent>(renderer);
-    game.add_event(r_event); */
+    // Create an EntityManager, and submit the entity into it.
+    auto ecs_manager = std::make_shared<se::EntityManager>();
+    ecs_manager->submit_entity(entity);
+    game.add_event(ecs_manager);
 
     auto camera = std::make_shared<se::Camera>(game.get_window(), core_shader, 70, glm::vec3(0, 0, 0));
     game.add_event(camera);
diff --git a/include/simpleengine/ecs/entity.h b/include/simpleengine/ecs/entity.h
index 8a2c8b0..bd061a1 100644
--- a/include/simpleengine/ecs/entity.h
+++ b/include/simpleengine/ecs/entity.h
@@ -18,6 +18,7 @@ namespace simpleengine {
      * 
      */
     class Entity : public simpleengine::Event, public simpleengine::Transformable {
+        // TODO: Don't extend from Event, create own destroy function
     private:
         static uint32_t incrementing_handle;
         uint32_t handle;
@@ -58,6 +59,8 @@ namespace simpleengine {
             for (auto& component : components) {
                 component->update(delta_time);
             }
+
+            rotate_y(delta_time * 10);
         }
 
         template<typename T>
diff --git a/include/simpleengine/entity_manager.h b/include/simpleengine/entity_manager.h
new file mode 100644
index 0000000..de7fe2d
--- /dev/null
+++ b/include/simpleengine/entity_manager.h
@@ -0,0 +1,25 @@
+#pragma once
+
+#include "ecs/entity.h"
+#include "event/event.h"
+
+#include <memory>
+#include <unordered_map>
+#include <vector>
+
+namespace simpleengine {
+    class EntityManager : public simpleengine::Event {
+    public:
+        std::unordered_map<uint32_t, std::shared_ptr<simpleengine::Entity>> entities;
+
+        EntityManager();
+
+        virtual void submit_entity(std::shared_ptr<simpleengine::Entity> entity);
+        virtual bool withdraw_entity(std::shared_ptr<simpleengine::Entity> entity);
+
+        virtual void initialize();
+        virtual void destroy() override;
+
+        virtual void update(const float& delta_time) override;
+    };
+}
\ No newline at end of file
diff --git a/src/entity_manager.cpp b/src/entity_manager.cpp
new file mode 100644
index 0000000..53e4c8e
--- /dev/null
+++ b/src/entity_manager.cpp
@@ -0,0 +1,40 @@
+#include "entity_manager.h"
+
+simpleengine::EntityManager::EntityManager() {
+
+}
+
+void simpleengine::EntityManager::submit_entity(std::shared_ptr<simpleengine::Entity> entity) {
+    entities.emplace(entity->get_handle(), entity);
+}
+
+bool simpleengine::EntityManager::withdraw_entity(std::shared_ptr<simpleengine::Entity> entity) {
+    auto it = entities.find(entity->get_handle());
+
+    if (it != entities.end()) {
+        it->second->destroy();
+        entities.erase(it);
+
+        return true;
+    }
+
+    return false;
+}
+
+void simpleengine::EntityManager::initialize() {
+
+}
+
+void simpleengine::EntityManager::destroy() {
+    std::cout << "Destroy entity manager!" << std::endl;
+
+    for (auto& [handle, entity] : entities) {
+        entity->destroy();
+    }
+}
+
+void simpleengine::EntityManager::update(const float& delta_time) {
+    for (auto& [handle, entity] : entities) {
+        entity->update(delta_time);
+    }
+}
\ No newline at end of file