Merge pull request #1 from SeanOMik/feature/ecs-and-submission-rendering

Feature/ecs and submission rendering

CMake/GetEnTT.cmake

@@ -0,0 +1,10 @@
+# Get the entt header libraries.
+include(FetchContent)
+FetchContent_Declare(
+    entt
+    GIT_REPOSITORY https://github.com/skypjack/entt.git
+    GIT_TAG v3.10.3
+)
+FetchContent_MakeAvailable(entt)
+message("Downloaded entt library to: ${entt_SOURCE_DIR}")
+set(ENTT_INCLUDE_DIR ${entt_SOURCE_DIR}/src)

CMakeLists.txt

@@ -4,6 +4,7 @@ project(SimpleEngine)
 
 include(cmrc/CMakeRC.cmake)
 include(CMake/GetStbLibraries.cmake)
+include(CMake/GetEnTT.cmake)
 
 # Add some CMake options:
 option(SIMPLE_ENGINE_BUILD_EXAMPLES "Build example projects" ON)
@@ -47,11 +48,11 @@ target_link_libraries(simpleengine PUBLIC ${OPENGL_LIBRARIES})
 target_link_libraries(simpleengine PUBLIC assimp)
 target_link_libraries(simpleengine PRIVATE simpleengine_resources)
 
-target_include_directories(simpleengine PUBLIC ${STB_INCLUDE_DIR})
-
 # Include some dependencies' include directories
 target_include_directories(simpleengine PUBLIC ${OPENGL_INCLUDE_DIR})
 target_include_directories(simpleengine PUBLIC ${GLM_INCLUDE_DIRS})
+target_include_directories(simpleengine PUBLIC ${STB_INCLUDE_DIR})
+target_include_directories(simpleengine PUBLIC ${ENTT_INCLUDE_DIR})
 
 # Add examples as a target if the user has them enabled
 if (SIMPLE_ENGINE_BUILD_EXAMPLES)

examples/dev_testing/resources/.gitignore

@@ -1,5 +1,2 @@
-*.blend
+*
-*.obj
+!shaders
-*.png
-*.bin
-*.gltf

examples/dev_testing/src/main.cpp

@@ -1,8 +1,9 @@
 #include "simpleengine/camera.h"
 #include "simpleengine/ecs/component/mesh_component.h"
 #include <simpleengine/ecs/component/model_component.h>
+#include "simpleengine/ecs/component/transform_component.h"
+#include <simpleengine/ecs/component/rotating_component.h>
 #include "simpleengine/ecs/entity.h"
-#include "simpleengine/entity_manager.h"
 #include "simpleengine/gfx/light.h"
 #include "simpleengine/gfx/material.h"
 #include "simpleengine/gfx/mesh.h"
@@ -10,7 +11,6 @@
 #include "simpleengine/gfx/renderer.h"
 #include "simpleengine/gfx/texture.h"
 #include "simpleengine/vector.h"
-#include <GLFW/glfw3.h>
 #include <simpleengine/gfx/shader.h>
 #include <simpleengine/renderable.h>
 #include <simpleengine/event/event.h>
@@ -19,8 +19,7 @@
 #include <simpleengine/vertex.h>
 #include <simpleengine/gfx/shaders/core_3d_shader.h>
 #include <simpleengine/gfx/model.h>
-
+#include <simpleengine/scene.h>
-//#include <simpleengine/scene.h>
 
 #include <glm/ext/matrix_clip_space.hpp>
 #include <glm/fwd.hpp>
@@ -166,29 +165,45 @@ int main(int argc, char *argv[]) {
         5, 6, 12, 12, 6, 13
     };
 
-    std::unordered_map<aiTextureType, std::vector<se::gfx::Texture>> textures;
+    std::unordered_map<aiTextureType, std::vector<std::shared_ptr<se::gfx::Texture>>> textures;
-    textures.emplace(white_texture.type, std::vector<se::gfx::Texture>{ white_texture });
+    textures.emplace(white_texture.type, std::vector<std::shared_ptr<se::gfx::Texture>>{ std::make_shared<se::gfx::Texture>(white_texture) });
     se::gfx::Material white_material(textures, 1.f, 0.f, 0.f, 0.f, 0.f);
 
+    // Create a renderer
+    auto renderer  = std::make_shared<se::gfx::Renderer>(game.get_window(), core_shader);
+    game.add_renderable(renderer);
+
+    // Create a Scene and give it the renderer
+    auto scene = std::make_shared<se::Scene>(renderer);
+    game.add_event(scene);
+
+    // Create an Entity in the Scene and add components to it.
+    se::ecs::Entity entity = scene->create_entity();
+    //entity.add_component<se::ModelComponent>("examples/dev_testing/resources/dragon.obj");
+    //entity.add_component<se::ModelComponent>("examples/dev_testing/resources/stall.obj");
+    
+    // Backpack model required vertically flipped texture coords.
+    auto& model_comp = entity.add_component<se::ModelComponent>("examples/dev_testing/resources/backpack/backpack.obj");
+    model_comp.model.vertically_flip_tex_coords();
+
+    //entity.add_component<se::ModelComponent>("examples/dev_testing/resources/scientist/scientist.fbx");
+    //entity.add_component<se::ModelComponent>("examples/dev_testing/resources/paradigm/paradigm.fbx");
+    //entity.add_component<se::RotatingComponent>();
+    auto& transform_comp = entity.add_component<se::TransformComponent>();
+    transform_comp.translate(15.f, -8.f, 0.f);
+    /* transform_comp.scale(0.1f);
+    transform_comp.rotate_z(-90.f);*/
+    transform_comp.rotate_x(-90.f);
+    
+
     // Create the entity and add the model component to it.
     /* auto entity = std::make_shared<simpleengine::Entity>();
     entity->add_component<se::MeshComponent>(cube_vertices, cube_indicies, white_material, true);
     entity->translate(3.5f, 0.f, 0.f); */
 
-    auto entity = std::make_shared<simpleengine::Entity>();
+    /* auto entity = std::make_shared<simpleengine::Entity>();
     entity->add_component<se::ModelComponent>("examples/dev_testing/resources/dragon.obj");
-    entity->translate(12.f, -4.f, 0.f);
+    entity->translate(12.f, -4.f, 0.f); */
-
-    // 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);
-
-    // 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);

include/simpleengine/ecs/component/component.h

@@ -1,31 +0,0 @@
-#pragma once
-
-#include "../../gfx/mesh.h"
-#include "../../event/event.h"
-
-#include <iostream>
-#include <vector>
-
-namespace simpleengine {
-    /**
-     * @brief A Model is a object that will be shown on the screen by a renderer.
-     * 
-     */
-    class Component : public simpleengine::Event {
-    private:
-        static uint32_t incrementing_handle;
-        uint32_t handle;
-    public:
-        Component() {
-            handle = incrementing_handle++;
-        }
-
-        uint32_t get_handle() {
-            return handle;
-        }
-
-        virtual void update(const float& delta_time) override {
-            std::cout << "Component update" << std::endl;
-        }
-    };
-}

include/simpleengine/ecs/component/mesh_component.h

@@ -1,6 +1,5 @@
 #pragma once
 
-#include "component.h"
 #include "../../gfx/mesh.h"
 #include "../../gfx/material.h"
 
@@ -9,37 +8,32 @@
 
 namespace simpleengine {
     /**
-     * @brief A Model is a object that will be shown on the screen by a renderer.
+     * @brief A component that contains a Mesh that will be rendered.
      * 
      */
-    class MeshComponent : public simpleengine::Component {
+    class MeshComponent {
     public:
-        gfx::Mesh model;
+        gfx::Mesh mesh;
-        //gfx::Material material;
 
-        MeshComponent(gfx::Mesh model) : model(model) {
+        MeshComponent(gfx::Mesh mesh) : mesh(mesh) {
 
         }
 
         MeshComponent(std::vector<LitVertex> vertices, std::vector<GLuint> indicies, gfx::Material material,
-                bool calculate_normals = false): model(vertices, indicies, material) {
+                bool calculate_normals = false): mesh(vertices, indicies, material) {
 
             if (calculate_normals) {
-                model.calculate_normals();
+                mesh.calculate_normals();
             }
         }
 
         MeshComponent(std::vector<LitVertex> vertices, std::vector<GLuint> indicies = std::vector<GLuint>(),
                 std::optional<gfx::Material> material = std::nullopt, bool calculate_normals = false) :
-                model(vertices, indicies, material) {
+                mesh(vertices, indicies, material) {
 
             if (calculate_normals) {
-                model.calculate_normals();
+                mesh.calculate_normals();
             }
         }
-
-        virtual void update(const float& delta_time) override {
-            
-        }
     };
 }

include/simpleengine/ecs/component/model_component.h

@@ -1,6 +1,5 @@
 #pragma once
 
-#include "component.h"
 #include "../../gfx/model.h"
 
 #include <iostream>
@@ -8,10 +7,10 @@
 
 namespace simpleengine {
     /**
-     * @brief A Model is a object that will be shown on the screen by a renderer.
+     * @brief A component that contains a Model that will be rendered.
      * 
      */
-    class ModelComponent : public simpleengine::Component {
+    class ModelComponent {
     public:
         gfx::Model model;
 
@@ -19,11 +18,8 @@ namespace simpleengine {
 
         }
 
-        ModelComponent(std::string model_file_path) : model(model_file_path) {
+        ModelComponent(std::string model_file_path, int model_processing_flags = gfx::ModelProcessingFlags::MdlProcFlag_NONE,
-
+            int assimp_flags = 0) : model(model_file_path, model_processing_flags, assimp_flags) {
-        }
-
-        virtual void update(const float& delta_time) override {
 
         }
     };

include/simpleengine/ecs/component/rotating_component.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <glm/glm.hpp>
+
+namespace simpleengine {
+    /**
+     * @brief A component that will rotate the transform every frame.
+     * 
+     */
+    class RotatingComponent {
+    public:
+        float rate;
+        glm::vec3 rotation_axis;
+
+        RotatingComponent() : rate(10.f), rotation_axis(glm::vec3(0, 1, 0)) {
+
+        }
+
+        RotatingComponent(float rate) : rate(rate), rotation_axis(glm::vec3(0, 1, 0)) {
+
+        }
+
+        RotatingComponent(glm::vec3 rotation_axis) : rotation_axis(rotation_axis) {
+
+        }
+
+        RotatingComponent(float rate, glm::vec3 rotation_axis) : rate(rate), rotation_axis(rotation_axis) {
+
+        }
+    };
+}

include/simpleengine/ecs/component/transform_component.h

@@ -0,0 +1,99 @@
+#pragma once
+
+#include <glm/ext/matrix_transform.hpp>
+#include <glm/glm.hpp>
+
+namespace simpleengine {
+    /**
+     * @brief A component that contains a Mesh that will be rendered.
+     * 
+     */
+    class TransformComponent {
+    public:
+        glm::mat4 transform_matrix;
+
+        TransformComponent() : transform_matrix(glm::mat4(1.f)) {
+            
+        }
+
+        TransformComponent(glm::mat4 transform_matrix) : transform_matrix(transform_matrix) {
+
+        }
+
+        friend TransformComponent operator+(TransformComponent lhs, const TransformComponent& rhs) {
+            lhs.transform_matrix += rhs.transform_matrix;
+            return lhs;
+        }
+
+        friend TransformComponent operator-(TransformComponent lhs, const TransformComponent& rhs) {
+            lhs.transform_matrix -= rhs.transform_matrix;
+            return lhs;
+        }
+
+        friend TransformComponent operator*(TransformComponent lhs, const TransformComponent& rhs) {
+            lhs.transform_matrix *= rhs.transform_matrix;
+            return lhs;
+        }
+
+        friend TransformComponent operator/(TransformComponent lhs, const TransformComponent& rhs) {
+            lhs.transform_matrix /= rhs.transform_matrix;
+            return lhs;
+        }
+
+        virtual void combine_transform(const glm::mat4& transform_matrix) {
+            this->transform_matrix *= transform_matrix;
+        }
+
+        virtual void combine_transform(const TransformComponent& transformable) {
+            transform_matrix = transformable.transform_matrix;
+        }
+
+        virtual void translate(float x, float y, float z) {
+            transform_matrix = glm::translate(transform_matrix, glm::vec3(x, y, z));
+        }
+
+        /* virtual void translate(const glm::vec3& vec) {
+            transform_matrix = glm::translate(transform_matrix, vec);
+        } */
+
+        virtual glm::mat4 rotation_matrix(float degrees, glm::vec3 rotation_axis) const {
+            return glm::rotate(transform_matrix, glm::radians(degrees), rotation_axis);
+        }
+
+        virtual glm::mat4 rotation_x_matrix(float degrees) const {
+            return rotation_matrix(degrees, glm::vec3(1, 0, 0));
+        }
+
+        virtual glm::mat4 rotation_y_matrix(float degrees) const {
+            return rotation_matrix(degrees, glm::vec3(0, 1, 0));
+        }
+
+        virtual glm::mat4 rotation_z_matrix(float degrees) const {
+            return rotation_matrix(degrees, glm::vec3(0, 0, 1));
+        }
+
+        virtual void rotate(float degrees, glm::vec3 rotation_axis) {
+            transform_matrix = rotation_matrix(degrees, rotation_axis);
+        }
+
+        virtual void rotate_x(float degrees) {
+            transform_matrix = rotation_x_matrix(degrees);
+        }
+        
+        virtual void rotate_y(float degrees) {
+            transform_matrix = rotation_y_matrix(degrees);
+        }
+
+        virtual void rotate_z(float degrees) {
+            transform_matrix = rotation_z_matrix(degrees);
+        }
+
+        virtual void scale(glm::vec3 scalar_vec) {
+            transform_matrix = glm::scale(transform_matrix, scalar_vec);
+        }
+
+        virtual void scale(float scalar) {
+            transform_matrix = glm::scale(transform_matrix, glm::vec3(scalar, scalar, scalar));
+        }
+    };
+}

include/simpleengine/ecs/entity.h

@@ -1,116 +1,266 @@
 #pragma once
 
-#include "component/component.h"
+#include "entt/entity/fwd.hpp"
-#include "../transformable.h"
+#include <cstddef>
-#include "../util.h"
+#include <entt/entt.hpp>
+#include <utility>
 
-#include <iterator>
+namespace simpleengine::ecs {
-#include <vector>
+    class Entity {
-#include <iostream>
-#include <chrono>
-#include <random>
-#include <bitset>
-#include <type_traits>
-
-namespace simpleengine {
-    /**
-     * @brief A Model is a object that will be shown on the screen by a renderer.
-     * 
-     */
-    class Entity : public simpleengine::Event, public simpleengine::Transformable {
-        // TODO: Don't extend from Event, create own destroy function
     private:
-        static uint32_t incrementing_handle;
+        entt::registry& registry;
-        uint32_t handle;
+        entt::entity inner;
     public:
-        std::vector<std::shared_ptr<Component>> components;
+        /* Entity(entt::entity entity) : inner(entity) {
-
-        Entity() : components({}) {
-            handle = incrementing_handle++;
-        }
-
-        /* Entity() : components({}) {
-            std::random_device rd; // obtain a random number from hardware
-            std::mt19937 gen(rd()); // seed the generator
-            std::uniform_int_distribution<uint16_t> distr(1, std::numeric_limits<std::uint16_t>::max());
-
-            uint16_t num = distr(gen);
-            uint32_t pid = simpleengine::util::get_current_pid();
-
-            handle |= num;
-            handle |= (pid << 16);
-
-            std::string binary = std::bitset<16>(num).to_string();
-            std::cout << "Entity handle: " << binary << std::endl;
 
         } */
 
-        Entity(std::vector<std::shared_ptr<Component>> components) : Entity() {
+        Entity(entt::registry& registry, entt::entity entity) : registry(registry), inner(entity) {
-            this->components = components;
+
         }
 
-        uint32_t get_handle() {
+        /**
-            return handle;
+         * @brief Checks if an identifier refers to a valid entity.
+         * 
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a1795b1221d728f806319a685930f520d
+         *
+         * @return true if the identifier is valid
+         * @return false otherwise
+         */
+        bool is_valid() const {
+            return registry.valid(inner);
         }
 
-        virtual void update(const float& delta_time) override {
+        /**
-            for (auto& component : components) {
+         * @brief Returns the actual version for an identifier. 
-                component->update(delta_time);
+         * 
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a199babc787d6baa6f7ccce761228a5f6
+         *
+         * @return entt::registry::version_type The version for the given identifier if valid, the tombstone version otherwise. 
+         */
+        entt::registry::version_type current_version() const {
+            return registry.current(inner);
         }
 
-            rotate_y(delta_time * 10); // TODO: Remove
+        /**
+         * @brief Releases an identifier.
+         *
+         * The version is updated and the identifier can be recycled at any time.
+         * 
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a3d9cb2368384b0952cb54848e777359e
+         *
+         * @return entt::registry::version_type The version of the recycled entity.
+         */
+        entt::registry::version_type release() {
+            return registry.release(inner);
         }
 
-        template<typename T>
+        /**
-        bool has_component() const {
+         * @brief Releases an identifier.
-            for (const auto& comp : components) {
+         *
-                if (std::dynamic_pointer_cast<T>(comp)) {
+         * The suggested version or the valid version closest to the suggested one is used instead of the implicitly generated version.
-                    return true;
+         * 
-                }
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#af9c919867fc93a7e1a2d0762ac3a9877
+         *
+         * @param version A desired version upon destruction.
+         * @return entt::registry::version_type The version actually assigned to the entity.
+         */
+        entt::registry::version_type release(entt::registry::version_type version) {
+            return registry.release(inner, version);
         }
 
-            return false;
+        /**
+         * @brief Destroys an entity and releases its identifier. 
+         * 
+         * @warning Adding or removing components to an entity that is being destroyed can result in undefined behavior. Attempting to use an invalid entity results in undefined behavior.
+         *
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a7b2c0368d508a6af2d094a9fc592a4a0
+         *
+         * @return entt::registry::version_type The version of the recycled entity.
+         */
+        entt::registry::version_type destroy() {
+            return registry.destroy(inner);
         }
 
-        template<typename T>
+        /**
-        std::shared_ptr<T> get_component() const {
+         * @brief Destroys an entity and releases its identifier.
-            for (const auto& comp : components) {
+         * 
-                if (std::shared_ptr<T> dyn_comp = std::dynamic_pointer_cast<T>(comp); dyn_comp) {
+         * The suggested version or the valid version closest to the suggested one is used instead of the implicitly generated version.
-                    return dyn_comp;
+         *
-                }
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#adc175a0d3bcf83a133c63890c674ceb3
+         *
+         * @param version A desired version upon destruction.
+         * @return entt::registry::version_type The version actually assigned to the entity.
+         */
+        entt::registry::version_type destroy(entt::registry::version_type version) {
+            return registry.destroy(inner, version);
         }
 
-            return nullptr;
+        /**
+         * @brief Assigns the given component to an entity. 
+         * 
+         * The component must have a proper constructor or be of aggregate type.
+         *
+         * @warning Attempting to use an invalid entity or to assign a component to an entity that already owns it results in undefined behavior.
+         *
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a4c9c0532972adc7a930a50888a97efdf
+         *
+         * @tparam Component Type of component to create. 
+         * @tparam Args Types of arguments to use to construct the component. 
+         * 
+         * @param args Parameters to use to initialize the component. 
+         * 
+         * @return decltype(auto) A reference to the newly created component. 
+         */
+        template<typename Component, typename... Args>
+        decltype(auto) add_component(Args&&... args) {
+            return registry.emplace<Component>(inner, std::forward<Args>(args)...);
         }
 
-        template<typename T>
+        /**
-        void add_component(std::shared_ptr<T> component) {
+         * @brief Assigns or replaces the given component for an entity.
-            static_assert(std::is_base_of_v<Component, T>, "Component class must derive from simpleengine::Component");
+         * 
-
+         * The component must have a proper constructor or be of aggregate type.
-            // Only allow one type of the same component
+         *
-            assert(!has_component<T>()); // TODO: Don't assert, give an error
+         * @warning Attempting to use an invalid entity or to assign a component to an entity that already owns it results in undefined behavior.
-            components.push_back(component);
+         *
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a3bbaebbb9365eef262453e42a8f7dc4b
+         *
+         * @tparam Component Type of component to assign or replace.
+         * @tparam Args Types of arguments to use to construct the component. 
+         * 
+         * @param args Parameters to use to initialize the component. 
+         * 
+         * @return decltype(auto) A reference to the newly created component. 
+         */
+        template<typename Component, typename... Args>
+        decltype(auto) add_or_replace_component(Args&&... args) {
+            return registry.emplace_or_replace<Component>(inner, std::forward<Args>(args)...);
         }
 
-        template<typename T>
+        /**
-        void add_component(T component) {
+         * @brief Replaces the given component for an entity. 
-            static_assert(std::is_base_of_v<Component, T>, "Component class must derive from simpleengine::Component");
+         *
-
+         * The component must have a proper constructor or be of aggregate type.
-            // Only allow one type of the same component
+         * 
-            assert(!has_component<T>()); // TODO: Don't assert, give an error
+         * @warning Attempting to use an invalid entity or to replace a component of an entity that doesn't own it results in undefined behavior.
-            components.push_back(std::make_shared<T>(component));
+         *
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a0501ff5a96a3421f3eec427bf5d62380
+         *
+         * @tparam Component Type of component to replace. 
+         * @tparam Args Types of arguments to use to construct the component. 
+         *
+         * @param args Parameters to use to initialize the component. 
+         *
+         * @return decltype(auto) A reference to the component being replaced. 
+         */
+        template<typename Component, typename... Args>
+        decltype(auto) replace_component(Args&&... args) {
+            return registry.replace<Component>(inner, std::forward<Args>(args)...);
         }
 
-        template<typename T, typename ...Args>
+        /**
-        std::shared_ptr<T> add_component(Args&&... args) {
+         * @brief Patches the given component for an entity. 
-            static_assert(std::is_base_of_v<Component, T>, "Component class must derive from simpleengine::Component");
+         * 
+         * The signature of the function should be equivalent to the following:
+         * \code{.cpp}
+         * void(Component &);
+         * \endcode
+         *
+         * @note Empty types aren't explicitly instantiated and therefore they are never returned. However, this function can be used to trigger an update signal for them.
+         *
+         * @warning Attempting to use an invalid entity or to patch a component of an entity that doesn't own it results in undefined behavior.
+         *
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a22454253689ff77e41326f849bfea976
+         *
+         * @tparam Component Type of component to patch. 
+         * @tparam Func Types of the function objects to invoke. 
+         * 
+         * @param func Valid function objects. 
+         *
+         * @return decltype(auto) A reference to the patched component. 
+         */
+        template<typename Component, typename... Func>
+        decltype(auto) patch(Func&&... func) {
+            return registry.patch<Component>(inner, std::forward<Func>(func)...);
+        }
 
-            // Only allow one type of the same component
+        /**
-            assert(!has_component<T>()); // TODO: Don't assert, give an error
+         * @brief Removes the given components from an entity. 
-            auto comp = std::make_shared<T>(std::forward<Args>(args)...);
+         * 
-            components.push_back(comp);
+         * @warning Attempting to use an invalid entity results in undefined behavior.
+         *
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#aa66ca71c5eb6c2e1b3bde6ff86a268c7
+         *
+         * @tparam Component Type of component to remove. 
+         * @tparam Other Other types of components to remove. 
+         *
+         * @return size_t The number of components actually removed. 
+         */
+        template<typename Component, typename... Other>
+        size_t remove_components() {
+            return registry.remove<Component, Other...>(inner);
+        }
 
-            return comp;
+        /**
+         * @brief Erases the given components from an entity. 
+         * 
+         * @warning Attempting to use an invalid entity or to erase a component from an entity that doesn't own it results in undefined behavior.
+         * 
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#ad7a51ade7ff181d7aa0b35915d0a4f2b
+         * 
+         * @tparam Component Types of components to erase. 
+         * @tparam Other Other types of components to erase. 
+         */
+        template<typename Component, typename... Other>
+        void erase() {
+            return registry.remove<Component, Other...>(inner);
+        }
+
+        /**
+         * @brief Checks if an entity has all the given components.
+         * 
+         * @warning Attempting to use an invalid entity results in undefined behavior.
+         *
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a40072eca607846f43f47d0e3f11dd196
+         * 
+         * @tparam Component Components for which to perform the check.
+         * 
+         * @return true if the entity has all the components
+         * @return false otherwise
+         */
+        template<typename... Component>
+        bool has_all_of() const {
+            return registry.all_of<Component...>(inner);
+        }
+
+        /**
+         * @brief Checks if an entity has at least one of the given components. 
+         * 
+         * @warning Attempting to use an invalid entity results in undefined behavior.
+         * 
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a08f819276fd2d8b2b2b6d01357f61a42
+         *
+         * @tparam Component Components for which to perform the check. 
+         * 
+         * @return true if the entity has at least one of the given components
+         * @return false otherwise
+         */
+        template<typename... Component>
+        bool has_any_of() const {
+            return registry.any_of<Component...>(inner);
+        }
+
+        /**
+         * @brief Checks if an entity has components assigned. 
+         * 
+         * @link https://skypjack.github.io/entt/classentt_1_1basic__registry.html#a10f5e61d4cabab9e9c1e87edc30de551
+         * 
+         * @return true if the entity has no components assigned
+         * @return false otherwise
+         */
+        bool has_any_components() const {
+            return registry.orphan(inner);
         }
     };
 }

include/simpleengine/entity_manager.h

@@ -1,25 +0,0 @@
-#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;
-    };
-}

include/simpleengine/gfx/material.h

@@ -3,12 +3,14 @@
 #include "texture.h"
 
 #include <assimp/material.h>
+
 #include <unordered_map>
+#include <memory>
 
 namespace simpleengine::gfx {
     class Material {
     public:
-        std::unordered_map<aiTextureType, std::vector<Texture>> textures;
+        std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>> textures;
 
         float ambient_scalar;
         float diffuse_scalar;
@@ -16,7 +18,7 @@ namespace simpleengine::gfx {
         float shine;
         float reflectivity;
 
-        Material(std::unordered_map<aiTextureType, std::vector<Texture>> textures, float shine = 1.f, float reflectivity = 0.f, float specular_scalar = 0.f, float ambient_scalar = 0.f, float diffuse_scalar = 0.f) :
+        Material(std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>> textures, float shine = 1.f, float reflectivity = 0.f, float specular_scalar = 0.f, float ambient_scalar = 0.f, float diffuse_scalar = 0.f) :
                 textures(textures), ambient_scalar(ambient_scalar), diffuse_scalar(diffuse_scalar), specular_scalar(specular_scalar),
                 shine(shine), reflectivity(reflectivity) {
 

include/simpleengine/gfx/mesh.h

@@ -23,6 +23,7 @@ namespace simpleengine::gfx {
         std::vector<LitVertex> vertices;
         std::vector<GLuint> indicies;
 
+        bool are_buffers_created = false;
         gfx::VBO ebo;
         gfx::VBO vbo;
         gfx::VAO vao;

include/simpleengine/gfx/model.h

@@ -10,6 +10,12 @@
 //#include <assimp/mesh.h>
 
 namespace simpleengine::gfx {
+    enum ModelProcessingFlags : uint8_t {
+        MdlProcFlag_NONE = 0b00000000,
+        MdlProcFlag_FLIP_TEX_COORDS_VERTICALLY = 0b00000001,
+        MdlProcFlag_FLIP_TEX_COORDS_HORIZONTALLY = 0b00000010,
+    };
+
     /**
      * @brief A Model is a group of Meshes read from the 3D model file.
      *
@@ -20,14 +26,25 @@ namespace simpleengine::gfx {
     class Model : public simpleengine::Transformable {
     protected:
         std::string model_directory; // May be needed
+        int additional_assimp_flags;
+        int model_processing_flags;
     public:
         std::vector<gfx::Mesh> meshes;
 
-        Model(std::string file_path);
+        Model(std::string file_path, int model_processing_flags = ModelProcessingFlags::MdlProcFlag_NONE, int assimp_flags = 0);
     
         void load_model(std::string path);
-        void process_node(aiNode* node, const aiScene* scene);
+        void process_node(std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>>& processed_textures, aiNode* node, const aiScene* scene);
-        gfx::Mesh process_mesh(aiMesh* mesh, const aiScene* scene);
+        gfx::Mesh process_mesh(std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>>& processed_textures, aiMesh* mesh, const aiScene* scene);
-        std::vector<Texture> load_material_textures(aiMaterial* material, aiTextureType type);
+
+        std::unordered_map<aiTextureType, std::vector<Texture>> load_all_textures(aiMaterial* material);
+        std::vector<std::shared_ptr<Texture>> load_material_texture(std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>>& processed_textures, aiMaterial* material, aiTextureType type);
+
+    protected:
+        void post_process();
+    public:
+
+        void vertically_flip_tex_coords();
+        void horizontally_flip_tex_coords();
     };
 }

include/simpleengine/gfx/renderer.h

@@ -1,45 +1,29 @@
 #pragma once
 
-#include "../ecs/entity.h"
-#include "material.h"
-#include "texture.h"
 #include "shader.h"
-//#include "renderable.h"
+#include "simpleengine/gfx/mesh.h"
-#include "mesh.h"
-#include "model.h"
 
 #include <unordered_map>
 #include <vector>
+#include <queue>
 
 namespace simpleengine::gfx {
+    class RenderingJob {
+    public:
+        gfx::Mesh& rendering_mesh;
+        glm::mat4 transform_mat;
+
+        RenderingJob(gfx::Mesh& mesh, glm::mat4 position) : rendering_mesh(mesh), transform_mat(position) {
+
+        }
+    };
+
     class Renderer : public simpleengine::Renderable {
     private:
         GLFWwindow* window;
     public:
 
-        class RenderingModel {
+        std::queue<RenderingJob> rendering_queue;
-        public:
-            std::shared_ptr<simpleengine::Entity> entity;
-            std::unordered_map<uint32_t, gfx::Mesh&> component_models;
-
-            RenderingModel(std::shared_ptr<simpleengine::Entity> entity) : entity(entity) {
-
-            }
-
-            /**
-             * @brief Create and delete buffers for new and old components in entity.
-             * 
-             */
-            void update_buffers();
-
-            /**
-             * @brief Destroy the buffers
-             * 
-             */
-            void destroy_buffers();
-        };
-
-        std::unordered_map<uint32_t, RenderingModel> rendering_models;
         gfx::Shader shader;
 
         Renderer(GLFWwindow* window, gfx::Shader shader);
@@ -47,8 +31,8 @@ namespace simpleengine::gfx {
 
         void enable_debug();
 
-        virtual void submit_entity(std::shared_ptr<simpleengine::Entity> entity);
+        virtual void queue_job(RenderingJob job);
-        virtual bool withdraw_entity(std::shared_ptr<simpleengine::Entity> entity);
+        virtual void create_job_buffers(RenderingJob& job);
 
         virtual void initialize();
         virtual void destroy() override;

include/simpleengine/gfx/texture.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstdint>
 #ifdef __linux__
 #include <GL/glew.h>
 #include <GL/gl.h>
@@ -17,6 +18,13 @@
 #include <iostream>
 
 namespace simpleengine::gfx {
+    enum TextureFlags : uint8_t {
+        TexFlags_IMG_2D = 0b00000001,
+        TexFlags_FLIP_VERTICALLY = 0b00000010,
+        TexFlags_FLIP_HORIZONTALLY = 0b00000100,
+        TexFlags_MIPMAP = 0b00001000,
+    };
+
     class Texture {
     private:
         unsigned char* img_data; // TODO Free this if its not used anymore
@@ -30,6 +38,7 @@ namespace simpleengine::gfx {
         int width;
         int channels;
         aiTextureType type;
+        std::string path;
 
         /**
          * @brief Construct a new Texture object from a path.
@@ -38,7 +47,8 @@ namespace simpleengine::gfx {
          * @param img_2d Whether or not the texture is 2D.
          * @param mipmap Whether or not to generate mipmaps for this texture.
          */
-        Texture(const char* path, aiTextureType type = aiTextureType::aiTextureType_DIFFUSE, bool img_2d = true, bool mipmap = true);
+        Texture(const char* path, aiTextureType type = aiTextureType::aiTextureType_DIFFUSE, int flags = TextureFlags::TexFlags_IMG_2D | 
+            TextureFlags::TexFlags_MIPMAP);
 
         /**
          * @brief Construct a new Texture object from the loaded file buffer.
@@ -48,7 +58,8 @@ namespace simpleengine::gfx {
          * @param img_2d Whether or not the texture is 2D.
          * @param mipmap Whether or not to generate mipmaps for this texture.
          */
-        Texture(const unsigned char *const buffer, int buffer_length, aiTextureType type = aiTextureType::aiTextureType_DIFFUSE, bool img_2d = true, bool mipmap = true);
+        Texture(const unsigned char *const buffer, int buffer_length, aiTextureType type = aiTextureType::aiTextureType_DIFFUSE, int flags = TextureFlags::TexFlags_IMG_2D | 
+            TextureFlags::TexFlags_MIPMAP);
 
         /**
          * @brief Construct a new Texture object from the loaded file buffer.
@@ -57,7 +68,8 @@ namespace simpleengine::gfx {
          * @param img_2d Whether or not the texture is 2D.
          * @param mipmap Whether or not to generate mipmaps for this texture.
          */
-        Texture(std::vector<unsigned char> buffer, aiTextureType type = aiTextureType::aiTextureType_DIFFUSE, bool img_2d = true, bool mipmap = true);
+        Texture(std::vector<unsigned char> buffer, aiTextureType type = aiTextureType::aiTextureType_DIFFUSE, int flags = TextureFlags::TexFlags_IMG_2D | 
+            TextureFlags::TexFlags_MIPMAP);
 
         static Texture white_texture();
 

include/simpleengine/scene.h

@@ -1,44 +1,32 @@
 #pragma once
 
+#include "entt/entity/fwd.hpp"
 #include "gfx/mesh.h"
-#include "entity.h"
 #include "event/event.h"
 #include "renderable.h"
+#include "simpleengine/gfx/renderer.h"
 
 #include <memory>
 
 #include <GLFW/glfw3.h>
 #include <vector>
 
+#include <entt/entt.hpp>
+
 namespace simpleengine {
+    namespace ecs {
+        class Entity;
+    }
+
     class Scene : public simpleengine::Event {
+    protected:
+        entt::registry registry;
+        std::shared_ptr<gfx::Renderer> renderer;
     public:
-        /**
+        Scene(std::shared_ptr<gfx::Renderer> renderer);
-         * @brief A list of entities in this scene.
-         * 
-         */
-        std::vector<std::shared_ptr<Entity>> entities;
 
-        /**
+        ecs::Entity create_entity();
-         * @brief Models that don't belong to an entity.
-         * 
-         */
-        std::vector<std::shared_ptr<gfx::Model>> stray_models;
 
-        Scene() = default;
+        virtual void update(const float& delta_time) override;
-
-        void add_entity(std::shared_ptr<Entity> entity) {
-            entities.push_back(entity);
-        }
-
-        void add_stray_model(std::shared_ptr<gfx::Model> stray) {
-            stray_models.push_back(stray);
-        }
-
-        virtual void update(const float& delta_time) override {
-            for (auto& entity : entities) {
-                entity->update(delta_time);
-            }
-        }
     };
 }

shell.nix

@@ -12,6 +12,5 @@ pkgs.mkShell {
     glfw
     glm
     assimp
-    (callPackage ./soil2.nix { })
   ];
 }

soil2.nix

@@ -1,37 +0,0 @@
-{ lib
-, stdenv
-, fetchFromGitHub
-, cmake
-, libGL
-, libX11
-}:
-
-stdenv.mkDerivation rec {
-  version = "39028e64921c03cabbc53b937da4a85aba264e00";
-  pname = "soil2";
-
-  src = fetchFromGitHub {
-    owner = "SpartanJ";
-    repo = pname;
-    rev = version;
-    sha256 = "sha256-zQQ8lwOkMCxdlf6zfnIOYVUTGVqnJuHL/LL8fbzxwHY=";
-  };
-
-  nativeBuildInputs = [ cmake libGL libX11 ];
-
-  installPhase = ''
-    runHook preInstall
-
-    cmake --build . --target install --config Release
-
-    runHook postInstall
-  '';
-
-  meta = with lib; {
-    description = "SOIL2 is a tiny C library used primarily for uploading textures into OpenGL.";
-    homepage = "https://github.com/SpartanJ/SOIL2";
-    license = licenses.mit0;
-    platforms = platforms.unix;
-    maintainers = with maintainers; [ seanomik ];
-  };
-}

src/camera.cpp

@@ -63,19 +63,19 @@ namespace simpleengine {
         }
 
         if (glfwGetKey(window, GLFW_KEY_UP) == GLFW_PRESS) {
-            rotation.z += camera_speed;
+            rotation.z += camera_speed * .3;
         }
 
         if (glfwGetKey(window, GLFW_KEY_DOWN) == GLFW_PRESS) {
-            rotation.z -= camera_speed;
+            rotation.z -= camera_speed * .3;
         }
 
         if (glfwGetKey(window, GLFW_KEY_LEFT) == GLFW_PRESS) {
-            rotation.y -= camera_speed;
+            rotation.y -= camera_speed * .3;
         }
 
         if (glfwGetKey(window, GLFW_KEY_RIGHT) == GLFW_PRESS) {
-            rotation.y += camera_speed;
+            rotation.y += camera_speed * .3;
         }
 
         // Limit the pitch of the camera.

src/ecs/component/component.cpp

@@ -1,3 +0,0 @@
-#include "ecs/component/component.h"
-
-uint32_t simpleengine::Component::incrementing_handle = 0;

src/ecs/entity.cpp

@@ -1,3 +0,0 @@
-#include "ecs/entity.h"
-
-uint32_t simpleengine::Entity::incrementing_handle = 0;

src/entity_manager.cpp

@@ -1,40 +0,0 @@
-#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);
-    }
-}

src/gfx/model.cpp

@@ -14,15 +14,26 @@
 #include <vector>
 
 namespace simpleengine::gfx {
-    Model::Model(std::string file_path) {
+    Model::Model(std::string file_path, int model_processing_flags, int assimp_flags): model_processing_flags(model_processing_flags),
+            additional_assimp_flags(assimp_flags) {
         load_model(file_path);
     }
 
+    void Model::post_process() {
+        if (model_processing_flags & ModelProcessingFlags::MdlProcFlag_FLIP_TEX_COORDS_VERTICALLY) {
+            vertically_flip_tex_coords();
+        }
+
+        if (model_processing_flags & ModelProcessingFlags::MdlProcFlag_FLIP_TEX_COORDS_HORIZONTALLY) {
+            horizontally_flip_tex_coords();
+        }
+    }
+
     void Model::load_model(std::string path) {
         Assimp::Importer importer;
 
         // assimp post processing options: http://assimp.sourceforge.net/lib_html/postprocess_8h.html
-        const aiScene *scene = importer.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs);
+        const aiScene *scene = importer.ReadFile(path, additional_assimp_flags | aiProcess_Triangulate | aiProcess_FlipUVs);
 
         if (!scene || scene->mFlags & AI_SCENE_FLAGS_INCOMPLETE || !scene->mRootNode) {
             std::cout << "ERROR::ASSIMP::" << importer.GetErrorString() << std::endl;
@@ -31,26 +42,28 @@ namespace simpleengine::gfx {
 
         model_directory = path.substr(0, path.find_last_of('/'));
 
-        process_node(scene->mRootNode, scene);
+        std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>> processed_textures;
+        process_node(processed_textures, scene->mRootNode, scene);
+
+        post_process();
     }
 
-    void Model::process_node(aiNode* node, const aiScene* scene) {
+    void Model::process_node(std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>>& processed_textures, aiNode* node, const aiScene* scene) {
         // process all the node's meshes (if any)
         for (int i = 0; i < node->mNumMeshes; i++) {
             aiMesh *mesh = scene->mMeshes[node->mMeshes[i]]; 
-            meshes.push_back(process_mesh(mesh, scene));			
+            meshes.push_back(process_mesh(processed_textures, mesh, scene));
         }
 
         // then do the same for each of its children
         for (int i = 0; i < node->mNumChildren; i++) {
-            process_node(node->mChildren[i], scene);
+            process_node(processed_textures, node->mChildren[i], scene);
         }
     }
 
-    gfx::Mesh Model::process_mesh(aiMesh* mesh, const aiScene* scene) {
+    gfx::Mesh Model::process_mesh(std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>>& processed_textures, aiMesh* mesh, const aiScene* scene) {
         std::vector<LitVertex> vertices;
         std::vector<unsigned int> indices;
-        std::vector<Texture> textures;
 
         for (unsigned int i = 0; i < mesh->mNumVertices; i++) {
             LitVertex vertex;
@@ -60,8 +73,10 @@ namespace simpleengine::gfx {
             simpleengine::Vectorf position(mesh->mVertices[i].x, mesh->mVertices[i].y, mesh->mVertices[i].z);
             vertex.position = position;
 
+            if (mesh->HasNormals()) {
                 glm::vec3 normal(mesh->mNormals[i].x, mesh->mNormals[i].y, mesh->mNormals[i].z);
                 vertex.normal = normal;
+            }
 
             if (mesh->mTextureCoords[0]) {
                 glm::vec2 tex_coord(mesh->mTextureCoords[0][i].x, mesh->mTextureCoords[0][i].y);
@@ -83,18 +98,18 @@ namespace simpleengine::gfx {
 
         // Create a default material and white texture.
         auto white_texture = gfx::Texture::white_texture();
-        std::unordered_map<aiTextureType, std::vector<Texture>> default_textures;
+        std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>> default_textures;
-        default_textures.emplace(white_texture.type, std::vector<Texture>{ white_texture });
+        default_textures.emplace(white_texture.type, std::vector<std::shared_ptr<Texture>>{ std::make_shared<Texture>(white_texture) });
         gfx::Material mat(default_textures, 1.f, 0.f, 0.f, 0.f, 0.f);
 
         if (mesh->mMaterialIndex >= 0) {
             std::cout << "TODO: Process model materials!" << std::endl;
 
-            std::unordered_map<aiTextureType, std::vector<Texture>> textures;
+            std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>> textures;
             aiMaterial *material = scene->mMaterials[mesh->mMaterialIndex];
 
             // Load Diffuse texture maps
-            std::vector<Texture> diffuse_maps = load_material_textures(material, aiTextureType_DIFFUSE);
+            std::vector<std::shared_ptr<Texture>> diffuse_maps = load_material_texture(processed_textures, material, aiTextureType_DIFFUSE);
             if (!diffuse_maps.empty()) textures.emplace(aiTextureType_DIFFUSE, diffuse_maps);
 
             // TODO Handle other types of texture maps
@@ -102,27 +117,97 @@ namespace simpleengine::gfx {
             if (!textures.empty()) {
                 // TODO: Find a way to let the user set the scalars.
                 mat = Material(textures, 1.f, 0.f, 0.f, 0.f, 0.f);
+
+                // Add `textures` into the `processed_textures` list.
+                for (const auto& pair : textures) {
+                    for (const auto& texture : pair.second) {
+                        bool contains = false;
+
+                        auto found = processed_textures.find(pair.first);
+                        if (found != processed_textures.end()) {
+                            for (const auto& processed_text : found->second) {
+                                if (processed_text->path == texture->path) {
+                                    contains = true;
+                                    break;
                                 }
                             }
 
-        return Mesh(vertices, indices, mat);
+                            if (!contains) {
+                                //found->second
+                                found->second.emplace_back(texture);
+                            }
+                        } else {
+                            processed_textures.emplace(pair.first, std::vector<std::shared_ptr<Texture>>{ pair.second });
+                        }
+                    }
+                }
+            }
         }
 
-    std::vector<Texture> Model::load_material_textures(aiMaterial* material, aiTextureType type) {
+        Mesh se_mesh(vertices, indices, mat);
-        std::vector<Texture> textures;
+
+        if (!mesh->HasNormals()) {
+            se_mesh.calculate_normals();
+        }
+
+        return se_mesh;
+    }
+
+    std::unordered_map<aiTextureType, std::vector<Texture>> load_all_textures(aiMaterial* material) {
+        // Load Diffuse texture maps
+        return {};
+    }
+
+    std::vector<std::shared_ptr<Texture>> Model::load_material_texture(std::unordered_map<aiTextureType, std::vector<std::shared_ptr<Texture>>>& processed_textures, aiMaterial* material, aiTextureType type) {
+        std::vector<std::shared_ptr<Texture>> textures;
 
         for (int i = 0; i < material->GetTextureCount(type); i++) {
-            aiString texture_path;
+            aiString texture_path_ai;
-            material->GetTexture(type, i, &texture_path);
+            material->GetTexture(type, i, &texture_path_ai);
+            std::string texture_path = texture_path_ai.C_Str();
+
+            // If the texture has been read, we should skip it.
+            bool skip = false;
+            for (const auto& pair : processed_textures) {
+                if (pair.first == type) {
+                    for (const auto& texture : pair.second) {
+                        if (texture->path == texture_path) {
+                            textures.emplace_back(texture); // Push a copy of the texture for this Mesh.
+                            skip = true;
+                            break;
+                        }
+                    }
+                }
+            }
+            if (skip) continue;
 
             std::stringstream ss;
-            ss << model_directory << "/" << texture_path.C_Str();
+            ss << model_directory << "/" << texture_path;
             std::string full_path = ss.str();
 
-            Texture texture(full_path.c_str(), type);
+            Texture texture(full_path.c_str(), type, /* TextureFlags::TexFlags_FLIP_VERTICALLY | */ TextureFlags::TexFlags_IMG_2D | TextureFlags::TexFlags_MIPMAP);
-            textures.emplace_back(texture);
+            texture.path = texture_path;
+            textures.emplace_back(std::make_shared<Texture>(texture));
+
+            std::cout << "Texture full path: " << full_path << ", texture_path: " << texture_path << std::endl;
         }
 
         return textures;
     }
+
+    void Model::vertically_flip_tex_coords() {
+        for (auto& mesh : meshes) {
+            for (auto& vertex : mesh.vertices) {
+                vertex.tex_coord.y *= -1;
+            }
+        }
+    }
+
+    void Model::horizontally_flip_tex_coords() {
+        for (auto& mesh : meshes) {
+            for (auto& vertex : mesh.vertices) {
+                vertex.tex_coord.x *= -1;
+            }
+        }
+    }
 } // namespace simpleengine::gfx

src/gfx/renderer.cpp

@@ -1,6 +1,4 @@
 #include "gfx/renderer.h"
-#include "ecs/component/component.h"
-#include "ecs/entity.h"
 #include "gfx/mesh.h"
 #include "gfx/vao.h"
 #include "renderable.h"
@@ -12,16 +10,7 @@
 #include <assimp/material.h>
 
 namespace simpleengine::gfx {
-    void create_mesh_buffers(std::shared_ptr<simpleengine::Component> comp, simpleengine::gfx::Mesh& mesh);
+    void create_mesh_buffers(simpleengine::gfx::Mesh& mesh);
-
-    void Renderer::RenderingModel::destroy_buffers() {
-        std::cout << "Destroying entity models..." << std::endl;
-
-        // Iterate through all buffer lists and destroy each inner buffer.
-        for (auto& pair : component_models) {
-            pair.second.destroy();
-        }
-    }
 
     Renderer::Renderer(GLFWwindow* window, gfx::Shader shader): window(window), shader(shader) {
         
@@ -45,24 +34,40 @@ namespace simpleengine::gfx {
         glDebugMessageCallback(debug_message_callback, 0);
     }
 
-    void Renderer::submit_entity(std::shared_ptr<simpleengine::Entity> entity) {
+    void Renderer::queue_job(RenderingJob job) {
-        std::cout << "Submitting entity (" << entity->get_handle() << ")..." << std::endl;
+        RenderingJob& emplace = rendering_queue.emplace(job);
-        auto it = rendering_models.emplace(entity->get_handle(), entity);
+        create_job_buffers(emplace);
-        it.first->second.update_buffers();
     }
 
-    bool Renderer::withdraw_entity(std::shared_ptr<simpleengine::Entity> entity) {
+    void Renderer::create_job_buffers(RenderingJob& job) {
-        std::cout << "Withdrawing entity (" << entity->get_handle() << ")...";
+        Mesh& rendering_mesh = job.rendering_mesh;
-        auto it = rendering_models.find(entity->get_handle());
 
-        if (it != rendering_models.end()) {
+        if (!rendering_mesh.are_buffers_created) {
-            it->second.destroy_buffers();
+            gfx::VBO& vbo = rendering_mesh.vbo;
-            rendering_models.erase(it);
+            gfx::VBO& ebo = rendering_mesh.ebo;
+            gfx::VAO& vao = rendering_mesh.vao;
 
-            return true;
+            vao.bind();
+            vbo.buffer(rendering_mesh.vertices.data(), 0, sizeof(LitVertex) * rendering_mesh.vertices.size());
+
+            if (!rendering_mesh.indicies.empty()) {
+                ebo.buffer(rendering_mesh.indicies.data(), 0, rendering_mesh.indicies.size() * sizeof(GLuint));
             }
 
-        return false;
+            // Enable VAO attributes
+            vao.enable_attrib(vbo, 0, 3, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, position), false);
+            vao.enable_attrib(vbo, 1, 3, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, color), false);
+            vao.enable_attrib(vbo, 2, 3, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, normal), false);
+            vao.enable_attrib(vbo, 3, 2, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, tex_coord), false);
+            vao.enable_attrib(vbo, 4, 1, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, texture_id), false);
+
+            glBindBuffer(GL_ARRAY_BUFFER, 0);
+            glBindVertexArray(0);
+
+            rendering_mesh.are_buffers_created = true;
+
+            std::cout << "Created render job buffers" << std::endl;
+        }
     }
 
     void Renderer::update(const float& delta_time) {
@@ -76,23 +81,22 @@ namespace simpleengine::gfx {
     void Renderer::destroy() {
         std::cout << "Destroying renderer..." << std::endl;
 
-        for (auto& [handle, rendering] : rendering_models) {
+        /* for (auto& [handle, rendering] : rendering_models) {
             rendering.destroy_buffers();
-        }
+        } */
     }
 
     void Renderer::render() {
         shader.use();
         
-        for (auto& [handle, rendering] : rendering_models) {
+        while (!rendering_queue.empty()) {
-            if (rendering.component_models.size() >= 0) {
+            // Get the job from the queue, we'll remove it after we render.
-                std::shared_ptr<Entity>& entity = rendering.entity;
+            RenderingJob& job = rendering_queue.front();
+            Mesh& mesh = job.rendering_mesh;
 
-                shader.set_uniform_matrix_4f("transform_matrix", entity->transform_matrix, false);
+            shader.set_uniform_matrix_4f("transform_matrix", job.transform_mat, false);
 
-                for (const auto& pair : rendering.component_models) {
+            std::optional<Material>& material = mesh.material;
-                    Mesh& model = pair.second;
-                    std::optional<Material>& material = model.material;
 
             shader.set_uniform_int("u_textures", 0, false);
 
@@ -107,82 +111,23 @@ namespace simpleengine::gfx {
                     if (texture_count >= 16) break;
 
                     glActiveTexture(GL_TEXTURE0 + texture_count);
-                            glBindTextureUnit(texture_count, texture.get_texture_id());
+                    glBindTextureUnit(texture_count, texture->get_texture_id());
 
                     texture_count++;
                 }
             }
             
-                    model.vao.bind();
+            mesh.vao.bind();
-                    if (model.indicies.empty()) {
+            if (mesh.indicies.empty()) {
-                        glDrawArrays(GL_TRIANGLES, 0, model.vertices.size());
+                glDrawArrays(GL_TRIANGLES, 0, mesh.vertices.size());
             } else {
-                        glDrawElements(GL_TRIANGLES, model.indicies.size(), GL_UNSIGNED_INT, 0);
+                glDrawElements(GL_TRIANGLES, mesh.indicies.size(), GL_UNSIGNED_INT, 0);
-                    }
-                }
             }
+            
+            // Now we'll remove the job from the queue.
+            rendering_queue.pop();
         }
 
         shader.unuse();
     }
-
-    void Renderer::RenderingModel::update_buffers() {
-        if (entity->has_component<simpleengine::MeshComponent>()) {
-            std::shared_ptr<MeshComponent> comp = entity->get_component<simpleengine::MeshComponent>();
-            auto iter = component_models.find(comp->get_handle());
-            if (iter == component_models.end()) {
-                std::cout << "Enabling buffer attributes for MeshComponent (" << comp->get_handle() << ")..." << std::endl;
-
-                //iter->second = comp->model;
-                gfx::Mesh& mesh = comp->model;
-                create_mesh_buffers(comp, mesh);
-                component_models.emplace(comp->get_handle(), mesh);
-
-                std::cout << "Enabled all buffer attributes for MeshComponent" << std::endl;
-            } else {
-                std::cout << "Already exists" << std::endl;
-            }
-        } else if (entity->has_component<simpleengine::ModelComponent>()) {
-            std::shared_ptr<ModelComponent> comp = entity->get_component<simpleengine::ModelComponent>();
-
-            auto iter = component_models.find(comp->get_handle());
-            if (iter == component_models.end()) {
-                std::cout << "Enabling buffer attributes for ModelComponent (" << comp->get_handle() << ")..." << std::endl;
-                
-                // Store all the model's meshes
-                for (auto& mesh : comp->model.meshes) {
-                    create_mesh_buffers(comp, mesh);
-
-                    component_models.emplace(comp->get_handle(), mesh);
-                }
-
-                std::cout << "Enabled all buffer attributes for ModelComponent" << std::endl;
-            } else {
-                std::cout << "Already exists" << std::endl;
-            }
-        }
-    }
-
-    void create_mesh_buffers(std::shared_ptr<Component> comp, gfx::Mesh& mesh) {
-        gfx::VBO& vbo = mesh.vbo;
-        gfx::VBO& ebo = mesh.ebo;
-        gfx::VAO& vao = mesh.vao;
-
-        vao.bind();
-        vbo.buffer(mesh.vertices.data(), 0, sizeof(LitVertex) * mesh.vertices.size());
-
-        if (!mesh.indicies.empty()) {
-            ebo.buffer(mesh.indicies.data(), 0, mesh.indicies.size() * sizeof(GLuint));
-        }
-
-        // Enable VAO attributes
-        vao.enable_attrib(vbo, 0, 3, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, position), false);
-        vao.enable_attrib(vbo, 1, 3, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, color), false);
-        vao.enable_attrib(vbo, 2, 3, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, normal), false);
-        vao.enable_attrib(vbo, 3, 2, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, tex_coord), false);
-        vao.enable_attrib(vbo, 4, 1, GL_FLOAT, sizeof(LitVertex), offsetof(LitVertex, texture_id), false);
-
-        glBindBuffer(GL_ARRAY_BUFFER, 0);
-        glBindVertexArray(0);
-    }
 }

src/gfx/texture.cpp

@@ -4,7 +4,11 @@
 #include <stb_image.h>
 
 namespace simpleengine::gfx {
-    Texture::Texture(const char* path, aiTextureType type, bool img_2d, bool mipmap): type(type) {
+    Texture::Texture(const char* path, aiTextureType type, int flags): type(type), path(path) {
+        bool img_2d = flags & TextureFlags::TexFlags_IMG_2D;
+        bool flip_vertically = flags & TextureFlags::TexFlags_FLIP_VERTICALLY;
+        bool mipmap = flags & TextureFlags::TexFlags_MIPMAP;
+
         image_type_gl = img_2d ? GL_TEXTURE_2D : GL_TEXTURE_3D;
 
         glGenTextures(1, &texture_id);
@@ -17,6 +21,8 @@ namespace simpleengine::gfx {
         glTexParameteri(image_type_gl, GL_TEXTURE_MIN_FILTER, linear_param);
         glTexParameteri(image_type_gl, GL_TEXTURE_MAG_FILTER, linear_param);
 
+        stbi_set_flip_vertically_on_load(flip_vertically);
+
         // Read 4 channels (RGBA)
         img_data = stbi_load(path, &width, &height, &channels, 4);
         if(!img_data) {
@@ -32,10 +38,16 @@ namespace simpleengine::gfx {
             glGenerateMipmap(image_type_gl);
         }
 
+        stbi_set_flip_vertically_on_load(false);
+
         unbind();
     }
 
-    Texture::Texture(const unsigned char *const buffer, int buffer_length, aiTextureType type, bool img_2d, bool mipmap): type(type) {
+    Texture::Texture(const unsigned char *const buffer, int buffer_length, aiTextureType type, int flags): type(type) {
+        bool img_2d = flags & TextureFlags::TexFlags_IMG_2D;
+        bool flip_vertically = flags & TextureFlags::TexFlags_FLIP_VERTICALLY;
+        bool mipmap = flags & TextureFlags::TexFlags_MIPMAP;
+
         image_type_gl = img_2d ? GL_TEXTURE_2D : GL_TEXTURE_3D;
 
         glGenTextures(1, &texture_id);
@@ -48,6 +60,8 @@ namespace simpleengine::gfx {
         glTexParameteri(image_type_gl, GL_TEXTURE_MIN_FILTER, linear_param);
         glTexParameteri(image_type_gl, GL_TEXTURE_MAG_FILTER, linear_param);
 
+        stbi_set_flip_vertically_on_load(flip_vertically);
+
         // Read 4 channels (RGBA)
         img_data = stbi_load_from_memory(buffer, buffer_length, &width, &height, &channels, 4);
         if(!img_data) {
@@ -63,11 +77,13 @@ namespace simpleengine::gfx {
             glGenerateMipmap(image_type_gl);
         }
 
+        stbi_set_flip_vertically_on_load(false);
+
         unbind();
     }
 
-    Texture::Texture(std::vector<unsigned char> buffer, aiTextureType type, bool img_2d, bool mipmap) :
+    Texture::Texture(std::vector<unsigned char> buffer, aiTextureType type, int flags) :
-        Texture(buffer.data(), buffer.size(), type, img_2d, mipmap) {
+        Texture(buffer.data(), buffer.size(), type, flags) {
         
     }
 

src/scene.cpp

@@ -0,0 +1,34 @@
+#include "scene.h"
+#include "ecs/component/mesh_component.h"
+#include "ecs/component/model_component.h"
+#include "ecs/component/transform_component.h"
+#include "ecs/component/rotating_component.h"
+#include "ecs/entity.h"
+#include "gfx/renderer.h"
+
+namespace simpleengine {
+    Scene::Scene(std::shared_ptr<gfx::Renderer> renderer) : renderer(renderer) {
+        
+    }
+
+    ecs::Entity Scene::create_entity() {
+        return ecs::Entity(registry, registry.create());
+    }
+
+    void Scene::update(const float& delta_time) {
+        // Is there a way these can be grouped?
+        registry.view<const TransformComponent, ModelComponent>().each([this](const TransformComponent& transform, ModelComponent& model_component) {
+            for (auto& mesh : model_component.model.meshes) {
+                renderer->queue_job(gfx::RenderingJob(mesh, transform.transform_matrix));
+            }
+        });
+
+        registry.view<const TransformComponent, MeshComponent>().each([this](const TransformComponent& transform, MeshComponent& mesh_component) {
+            renderer->queue_job(gfx::RenderingJob(mesh_component.mesh, transform.transform_matrix));
+        });
+
+        registry.view<TransformComponent, RotatingComponent>().each([this, &delta_time](TransformComponent& transform, RotatingComponent& rotating) {
+            transform.rotate(rotating.rate * delta_time, rotating.rotation_axis);
+        });
+    }
+}