modified scene system

src/Components.h

@@ -20,8 +20,10 @@ namespace Components {
     };
 
     struct Relationship {
-        entt::entity entity;
+        entt::entity parent {entt::null};
-        std::vector<entt::entity> children;
+        entt::entity first_child {entt::null};
+        entt::entity prev_sibling {entt::null};
+        entt::entity next_sibling {entt::null};
     };
 
     struct Drawable {

src/ModelManager.cpp

@@ -61,7 +61,6 @@ std::shared_ptr<Model> ModelManager::load_from_file(std::string_view _path, bool
         model->materials.push_back(std::make_shared<Material>(mat));
     }
 
-    model->meshes.resize(scene->mNumMeshes);
     for (unsigned int i = 0; i < scene->mNumMeshes; i++) {
         aiMesh* aiMesh = scene->mMeshes[i];
         Mesh mesh{};
@@ -80,22 +79,22 @@ std::shared_ptr<Model> ModelManager::load_from_file(std::string_view _path, bool
     return model;
 }
 
-void process_ai_node(aiNode* aiNode, const aiScene* scene, glm::mat4 transform, ModelNode* node)
+void process_ai_node(aiNode* aiNode, const aiScene* scene, glm::mat4 transform, ModelNode& node)
 {
     const auto t = aiNode->mTransformation;
     transform = transform * glm::mat4(t.a1, t.a2, t.a3, t.a4, t.b1, t.b2, t.b3, t.b4, t.c1, t.c2, t.c3, t.c4, t.d1, t.d2, t.d3, t.d4);
 
-    node->transform = transform;
+    node.transform = transform;
 
     for (unsigned int i = 0; i < aiNode->mNumMeshes; i++) {
-        node->meshIndices.push_back(aiNode->mMeshes[i]);
+        node.meshIndices.push_back(aiNode->mMeshes[i]);
     }
 
     for (unsigned int i = 0; i < aiNode->mNumChildren; i++)
     {
         ModelNode newNode{};
         process_ai_node(aiNode->mChildren[i], scene, transform, newNode);
-        node->children.push_back(newNode);
+        node.children.push_back(newNode);
     }
 }
 

src/Scene.cpp

@@ -4,7 +4,61 @@
 
 #include "Scene.h"
 
-entt::entity Scene::create_game_obejct() {
+#include "Components.h"
+
+Scene::Scene() {
+    root = _registry.create();
+    attach_component<Components::Transform>(root);
+    attach_component<Components::Relationship>(root);
+}
+
+entt::entity Scene::create_game_object() {
+    return create_game_object(root);
+}
+
+entt::entity Scene::create_game_object(entt::entity parent) {
     const entt::entity entity = _registry.create();
+    attach_component<Components::Transform>(entity);
+    attach_component<Components::Relationship>(entity);
+
+    add_child(parent, entity);
+
     return entity;
 }
+
+template<typename T>
+T& Scene::attach_component(entt::entity e) {
+    return _registry.emplace<T>(e);
+}
+
+template<typename T>
+T &Scene::attach_component(entt::entity e, T data) {
+    return _registry.emplace<T>(e, data);
+}
+
+template<typename T>
+T& Scene::fetch_component(entt::entity e) {
+    return _registry.get<T>(e);
+}
+
+void Scene::add_child(entt::entity parent, entt::entity child) {
+    auto& parentRelationship = fetch_component<Components::Relationship>(parent);
+
+    if (parentRelationship.first_child == entt::null) {
+        parentRelationship.first_child = child;
+        return;
+    }
+
+    entt::entity lastSibling = parentRelationship.first_child;
+    auto& lastSiblingRelationship = fetch_component<Components::Relationship>(lastSibling);
+    while (lastSiblingRelationship.next_sibling != entt::null) {
+        lastSibling = lastSiblingRelationship.next_sibling;
+        lastSiblingRelationship = fetch_component<Components::Relationship>(lastSibling);
+    }
+    lastSiblingRelationship.next_sibling = child;
+
+    auto& childRelationship = fetch_component<Components::Relationship>(child);
+    childRelationship.prev_sibling = lastSibling;
+    childRelationship.next_sibling = entt::null;
+    childRelationship.parent = parent;
+}

src/Scene.h

@@ -7,14 +7,33 @@
 
 #include "entt/entt.hpp"
 
+struct SceneObject {
+    entt::entity e;
+    std::vector<SceneObject*> children;
+};
+
 class Scene {
 public:
-    Scene() = default;
+    Scene();
     ~Scene() = default;
 
-    entt::entity create_game_obejct();
+    entt::entity create_game_object();
+    entt::entity create_game_object(entt::entity parent);
+
+    template<typename T>
+    T& attach_component(entt::entity e);
+    template<typename T>
+    T& attach_component(entt::entity e, T data);
+
+    template<typename T>
+    T& fetch_component(entt::entity e);
+
+
 private:
     entt::registry _registry{};
+    entt::entity root;
+
+    void add_child(entt::entity parent, entt::entity child);
 };
 
 #endif //B_ENGINE_SCENE_H

src/main.cpp

@@ -250,20 +250,17 @@ void loop() {
         // draw the stuff
         if (shader && activeModel) {
             shader->bind();
-
             shader->setMat4("projection", gCamera.projection());
             shader->setMat4("view", gCamera.view());
             shader->setMat4("model", model);
-
             shader->setVec3("viewPosition", gCamera.position());
-
             shader->setVec3("lightPosition", glm::vec3{-2.f, 0, 2.0f});
             shader->setVec3("lightDirection", glm::vec3(1, -1, 1));
             shader->setVec3("lightAmbient",   glm::vec3(0.3f, 0.3f, 0.3f));
             shader->setVec3("lightDiffuse",   glm::vec3(0.5f, 0.5f, 0.5f));
             shader->setVec3("lightSpecular",  glm::vec3(1.0f, 1.0f, 1.0f));
 
-            for (const auto& mesh: activeModel->meshes) {
+            /*for (const auto& mesh: activeModel->meshes) {
                 unsigned int materialId = 0;
                 if (materialId >= activeModel->materials.size()) {
                     materialId = 0;
@@ -294,7 +291,7 @@ void loop() {
 
                 glBindVertexArray(mesh.get()->vao);
                 glDrawElements(GL_TRIANGLES, mesh->numIndices, GL_UNSIGNED_INT, 0);
-            }
+            }*/
 
             glBindVertexArray(0);
             ShaderProgram::unbind();