//
// Created by edward on 23-3-25.
//

#include "Mesh.h"

Mesh::Mesh(std::vector<Vertex> vertices, std::vector<unsigned int> indices, std::vector<Texture> textures)
    : vertices_(std::move(vertices))
    , indices_(std::move(indices))
    , textures_(std::move(textures))
    {
    setup();
}

void Mesh::setup() {
    glGenVertexArrays(1, &VAO_);
    glGenBuffers(1, &VBO_);
    glGenBuffers(1, &EBO_);

    glBindVertexArray(VAO_);
    glBindBuffer(GL_ARRAY_BUFFER, VBO_);
    glBufferData(GL_ARRAY_BUFFER, vertices_.size() * sizeof(Vertex), vertices_.data(), GL_STATIC_DRAW);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *) offsetof(Vertex, position));
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *) offsetof(Vertex, color));
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *) offsetof(Vertex, normal));
    glEnableVertexAttribArray(2);
    glVertexAttribPointer(3, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *) offsetof(Vertex, texCoords));
    glEnableVertexAttribArray(3);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO_);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices_.size() * sizeof(unsigned int), indices_.data(), GL_STATIC_DRAW);/// copy data to EBO

    /// set wireframe mode
    // glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

    /// unbind VBO -> is allowed, but not necessary
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    /// unbind VAO
    glBindVertexArray(0);

}

void Mesh::draw(Shader *shader) {
    for (unsigned i = 0; i < textures_.size(); ++i) {
        textures_[i].use(shader, i);
    }

    glBindVertexArray(VAO_);
    glDrawElements(GL_TRIANGLES, indices_.size(), GL_UNSIGNED_INT, 0);
}

/*
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
*/