4 files changed, 144 insertions, 0 deletions
diff --git a/mwe/ecs-memory-efficient/src/ComponentManager.cpp b/mwe/ecs-memory-efficient/src/ComponentManager.cpp
new file mode 100644
index 0000000..16cc2b6
--- /dev/null
+++ b/mwe/ecs-memory-efficient/src/ComponentManager.cpp
@@ -0,0 +1,21 @@
+#include "ComponentManager.h"
+
+ComponentManager ComponentManager::mInstance;
+
+ComponentManager& ComponentManager::GetInstance() {
+	return mInstance;
+}
+
+ComponentManager::ComponentManager() {}
+
+void ComponentManager::DeleteAllComponentsOfId(std::uint32_t id) {
+    for(auto& [type, componentArray] : mComponents) {	//Loop through all the types (in the unordered_map<>)
+        if (id < componentArray.size()) {	//Make sure that the id (that we are looking for) is within the boundaries of the vector<>
+            componentArray[id].clear();	//Clear the components at this specific id
+        }
+    }
+}
+
+void ComponentManager::DeleteAllComponents() {
+	mComponents.clear();	//Clear the whole unordered_map<>
+}
diff --git a/mwe/ecs-memory-efficient/src/Components.cpp b/mwe/ecs-memory-efficient/src/Components.cpp
new file mode 100644
index 0000000..69b5eaa
--- /dev/null
+++ b/mwe/ecs-memory-efficient/src/Components.cpp
@@ -0,0 +1,10 @@
+#include "Components.h"
+#include <iostream>
+
+Component::Component() : mActive(true) {}
+
+Sprite::Sprite(std::string path) : mPath(path) {}
+
+Rigidbody::Rigidbody(int mass, int gravityScale, int bodyType) : mMass(mass), mGravityScale(gravityScale), mBodyType(bodyType) {}
+
+Colider::Colider(int size) : mSize(size) {}
diff --git a/mwe/ecs-memory-efficient/src/GameObjectMax.cpp b/mwe/ecs-memory-efficient/src/GameObjectMax.cpp
new file mode 100644
index 0000000..62c41de
--- /dev/null
+++ b/mwe/ecs-memory-efficient/src/GameObjectMax.cpp
@@ -0,0 +1,5 @@
+#include "GameObjectMax.h"
+
+#include "ComponentManager.h"
+
+GameObject::GameObject(std::uint32_t id, std::string name, std::string tag, int layer) : mId(id), mName(name), mTag(tag), mActive(true), mLayer(layer) {}
diff --git a/mwe/ecs-memory-efficient/src/main.cpp b/mwe/ecs-memory-efficient/src/main.cpp
new file mode 100644
index 0000000..9e8fbd5
--- /dev/null
+++ b/mwe/ecs-memory-efficient/src/main.cpp
@@ -0,0 +1,108 @@
+#include <iostream>
+#include <vector>
+#include <cstdint>
+
+#include "ComponentManager.h"
+#include "GameObjectMax.h"
+#include "Components.h"
+
+int main() {
+	GameObject gameObect0(0, "Name: 0", "Tag: 0", 0);	//Entity 0
+	GameObject gameObect1(1, "Name: 1", "Tag: 1", 1);	//Entity 1
+	GameObject gameObect2(2, "Name: 2", "Tag: 2", 2);	//Entity 2
+	GameObject gameObect3(3, "Name: 3", "Tag: 3", 3);	//Entity 3
+	GameObject gameObect4(4, "Name: 4", "Tag: 4", 4);	//Entity 4
+	GameObject gameObect5(5, "Name: 5", "Tag: 5", 5);	//Entity 5
+	GameObject gameObect6(6, "Name: 6", "Tag: 6", 6);	//Entity 6
+	GameObject gameObect7(7, "Name: 7", "Tag: 7", 7);	//Entity 7
+
+	gameObect0.AddComponent<Sprite>("C:/object0");	//Add a sprite to entity0
+	gameObect0.AddComponent<Rigidbody>(1, 2, 3);	//Also add a rigidbody to entity0
+	gameObect0.AddComponent<Rigidbody>(3, 2, 1);	//Add a second rigidbody to entity0
+
+	gameObect1.AddComponent<Rigidbody>(4, 5, 6);	//Only add a rigidbody to entity1
+
+	gameObect2.AddComponent<Sprite>("C:/object2/1");	//Add four sprites to entity2
+	gameObect2.AddComponent<Sprite>("C:/object2/2");
+	gameObect2.AddComponent<Sprite>("C:/object2/3");
+	gameObect2.AddComponent<Sprite>("C:/object2/4");
+	gameObect2.AddComponent<Rigidbody>(10, 100, 500);	//Add four rigidbodies to entity2
+	gameObect2.AddComponent<Rigidbody>(10, 100, 501);
+	gameObect2.AddComponent<Rigidbody>(10, 100, 502);
+	gameObect2.AddComponent<Rigidbody>(10, 100, 500);
+	
+	//Add non components to entity3, entity4, entity5 and entity6
+
+	gameObect7.AddComponent<Sprite>("C:/object7");	//Add a sprite to entity 7
+	gameObect7.AddComponent<Colider>(30);	//Add a colder to entity 7
+
+	//The entities are now initialized
+	//Now I will demonstrate some ways of retreiving/getting components
+
+	std::cout << "Finding all sprites of entity 0" << std::endl;
+	std::vector<std::reference_wrapper<Sprite>> spriteOfEntity0 = ComponentManager::GetInstance().GetComponentsByID<Sprite>(gameObect0.mId);
+	for(Sprite& spriteEntity0 : spriteOfEntity0) {
+		std::cout << "Sprite of entity 0: " << spriteEntity0.mPath << std::endl;
+	}
+	std::cout << std::endl;
+
+	std::cout << "Finding all rigidbodies of entity 0" << std::endl;
+	std::vector<std::reference_wrapper<Rigidbody>> rigidbodyOfEntity0 = ComponentManager::GetInstance().GetComponentsByID<Rigidbody>(gameObect0.mId);
+	for(Rigidbody& rigidbodyEntity0 : rigidbodyOfEntity0) {
+		std::cout << "Rigidbody of entity 0: " << rigidbodyEntity0.mMass << " " << rigidbodyEntity0.mGravityScale << " " << rigidbodyEntity0.mBodyType << std::endl;
+
+		rigidbodyEntity0.mMass = 15;
+	}
+	std::cout << std::endl;
+
+	std::cout << "Finding all coliders of entity 0" << std::endl;
+	std::vector<std::reference_wrapper<Colider>> coliderOfEntity0 = ComponentManager::GetInstance().GetComponentsByID<Colider>(gameObect0.mId);
+	for(Colider& coliderEntity0 : coliderOfEntity0) {
+		std::cout << "Colider of entity 0: " << coliderEntity0.mSize << std::endl;
+	}
+	std::cout << std::endl;
+
+	std::cout << "Finding all sprites of entity 3" << std::endl;
+	std::vector<std::reference_wrapper<Sprite>> spriteOfEntity3 = ComponentManager::GetInstance().GetComponentsByID<Sprite>(gameObect3.mId);
+	for(Sprite& spriteEntity3 : spriteOfEntity3) {
+		std::cout << "Sprite of entity 3: " << spriteEntity3.mPath << std::endl;
+	}
+	std::cout << std::endl;
+
+	std::cout << "Finding all rigidbodies of entity 3" << std::endl;
+	std::vector<std::reference_wrapper<Rigidbody>> rigidbodyOfEntity3 = ComponentManager::GetInstance().GetComponentsByID<Rigidbody>(gameObect3.mId);
+	for(Rigidbody& rigidbodyEntity3 : rigidbodyOfEntity3) {
+		std::cout << "Rigidbody of entity 3: " << rigidbodyEntity3.mMass << " " << rigidbodyEntity3.mGravityScale << " " << rigidbodyEntity3.mBodyType << std::endl;
+	}
+	std::cout << std::endl;
+
+	std::cout << "Finding all sprites of all entities" << std::endl;
+	std::vector<std::pair<std::reference_wrapper<Sprite>, std::uint32_t>> sprites = ComponentManager::GetInstance().GetComponentsByType<Sprite>();
+	for(auto& [sprite, id] : sprites) {
+		std::cout << "Sprite of id: " << id << ": " << sprite.get().mPath << std::endl;
+	}
+	std::cout << std::endl;
+
+	std::cout << "Finding all coliders of all entities" << std::endl;
+	std::vector<std::pair<std::reference_wrapper<Colider>, std::uint32_t>> coliders = ComponentManager::GetInstance().GetComponentsByType<Colider>();
+	for(auto& [colider, id] : coliders) {
+		std::cout << "Colder of id: " << id << ": " << colider.get().mSize << std::endl;
+	}
+	std::cout << std::endl;
+
+	std::cout << "Finding all rigidbodies of all entities" << std::endl;
+	std::vector<std::pair<std::reference_wrapper<Rigidbody>, std::uint32_t>> rigidBodies = ComponentManager::GetInstance().GetComponentsByType<Rigidbody>();
+	for(auto& [rigidbody, id] : rigidBodies) {
+		std::cout << "Rigidbody of id: " << id << ": " << rigidbody.get().mMass << " " << rigidbody.get().mGravityScale << " " << rigidbody.get().mBodyType << std::endl;
+
+		rigidbody.get().mMass = -1;
+	}
+	std::cout << std::endl;
+
+	std::cout << "Finding all rigidbodies of all entities for the second time (after changing mMass to -1)" << std::endl;
+	std::vector<std::pair<std::reference_wrapper<Rigidbody>, std::uint32_t>> rigidBodies2 = ComponentManager::GetInstance().GetComponentsByType<Rigidbody>();
+	for(auto& [rigidbody2, id2] : rigidBodies2) {
+		std::cout << "Rigidbody of id: " << id2 << ": " << rigidbody2.get().mMass << " " << rigidbody2.get().mGravityScale << " " << rigidbody2.get().mBodyType << std::endl;
+	}
+	std::cout << std::endl;
+}