ThreeLab/Engine/Components/ModelComponent.h

#ifndef MODEL_COMPONENT_H
#define MODEL_COMPONENT_H

#include <string>
#include <vector>
#include <GL/glew.h>
#include <glm/glm.hpp>
#include <yaml-cpp/yaml.h>

// Structure representing a single vertex.
struct Vertex {
    glm::vec3 Position;
    glm::vec3 Normal;
    glm::vec2 TexCoords;
    glm::vec3 Tangent;
};

// Structure representing a sub-mesh (a group of faces sharing the same material)
struct SubMesh {
    std::vector<Vertex> vertices;
    std::vector<GLuint> indices;
    glm::vec3 diffuseColor;
    glm::vec3 specularColor;
    float shininess;
    GLuint diffuseTexture;
    // (Optional) If you add a normal texture per submesh.
    // GLuint normalTexture;
    GLuint VAO, VBO, EBO;

    SubMesh()
        : diffuseColor(1.0f,1.0f,1.0f),
          specularColor(1.0f,1.0f,1.0f),
          shininess(32.0f),
          diffuseTexture(0),
          VAO(0), VBO(0), EBO(0)
    {}
};

class ModelComponent {
public:
    ModelComponent();
    ~ModelComponent();

    // Base model file path.
    std::string modelPath;
    // Submeshes.
    std::vector<SubMesh> meshes;

    // Global material overrides (if any).
    glm::vec3 diffuseColor;
    glm::vec3 specularColor;
    float shininess;

    // Functions.
    bool LoadModel(const std::string &filepath);
    void Draw();

    // Texture loading.
    bool LoadDiffuseTexture(const std::string &filepath, GLuint &textureID);
    bool LoadNormalTexture(const std::string &filepath);
    
    // Setup mesh for a submesh.
    void SetupMesh(SubMesh &mesh);

    // --- YAML Serialization Functions (Globals Only) ---
    // Save the global ModelComponent state to a YAML node.
    YAML::Node Save() const {
        YAML::Node node;
        node["modelPath"] = modelPath;

        node["globalDiffuseColor"] = YAML::Node();
        node["globalDiffuseColor"].push_back(diffuseColor.x);
        node["globalDiffuseColor"].push_back(diffuseColor.y);
        node["globalDiffuseColor"].push_back(diffuseColor.z);

        node["globalSpecularColor"] = YAML::Node();
        node["globalSpecularColor"].push_back(specularColor.x);
        node["globalSpecularColor"].push_back(specularColor.y);
        node["globalSpecularColor"].push_back(specularColor.z);

        node["globalShininess"] = shininess;

        return node;
    }

    // Load the global ModelComponent state from a YAML node.
    void Load(const YAML::Node &node) {
        if (node["modelPath"]) {
            modelPath = node["modelPath"].as<std::string>();
        }
        if (node["globalDiffuseColor"]) {
            diffuseColor.x = node["globalDiffuseColor"][0].as<float>();
            diffuseColor.y = node["globalDiffuseColor"][1].as<float>();
            diffuseColor.z = node["globalDiffuseColor"][2].as<float>();
        }
        if (node["globalSpecularColor"]) {
            specularColor.x = node["globalSpecularColor"][0].as<float>();
            specularColor.y = node["globalSpecularColor"][1].as<float>();
            specularColor.z = node["globalSpecularColor"][2].as<float>();
        }
        if (node["globalShininess"]) {
            shininess = node["globalShininess"].as<float>();
        }
        // Reload the model (populates meshes based on the modelPath).
        LoadModel(modelPath);
    }
};

#endif // MODEL_COMPONENT_H