initiliaze.cpp

bool OpenGL_Mesh::Initialize()
  {

    _vao = 0;
    _vbo = 0;
    _nvbo = 0;
    _uvbo = 0;
    _ebo = 0;

    glGenVertexArrays(1, &_vao);
    glGenBuffers(1, &_vbo);
    glGenBuffers(1, &_nvbo);
    glGenBuffers(1, &_uvbo);

    if (!_indices.empty())
    {
      glGenBuffers(1, &_ebo);
    }

    glBindVertexArray(_vao);

    // vbo - vertices
    glBindBuffer(GL_ARRAY_BUFFER, _vbo);
    glBufferData(
      GL_ARRAY_BUFFER,
      static_cast<GLsizeiptr>(_vertices.size() * sizeof(float)),
      &_vertices[0],
      GL_STATIC_DRAW);

    glVertexAttribPointer(
      0,
      3,
      GL_FLOAT,
      GL_FALSE,
      3 * sizeof(GLfloat),
      static_cast<void *>(nullptr));
    glEnableVertexAttribArray(0);

    // nvbo - normals
    glBindBuffer(GL_ARRAY_BUFFER, _nvbo);
    glBufferData(GL_ARRAY_BUFFER,
                 static_cast<GLsizeiptr>(_normals.size() * sizeof(float)),
                 &_normals[0],
                 GL_STATIC_DRAW);

    glVertexAttribPointer(
      1,
      3,
      GL_FLOAT,
      GL_FALSE,
      3 * sizeof(GLfloat),
      static_cast<void *>(nullptr));
    glEnableVertexAttribArray(1);

    // uvbo - texture coordinates
    glBindBuffer(GL_ARRAY_BUFFER, _uvbo);
    glBufferData(GL_ARRAY_BUFFER,
                 static_cast<GLsizeiptr>(_uvs.size() * sizeof(float)),
                 &_uvs[0],
                 GL_STATIC_DRAW);

    glVertexAttribPointer(
      2,
      2,
      GL_FLOAT,
      GL_FALSE,
      2 * sizeof(GLfloat),
      static_cast<void *>(nullptr));
    glEnableVertexAttribArray(2);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _ebo);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,
                 static_cast<GLsizeiptr>(_indices.size() * sizeof(int)),
                 &_indices[0],
                 GL_STATIC_DRAW);
    
    glBindBuffer(GL_ARRAY_BUFFER, 0);
  
    glBindVertexArray(0);

    return true;
  }