void Parallelpiped::init()
{
 glm::vec3 pu = p + u;
 glm::vec3 pv = p + v;
 glm::vec3 pw = p + w;
 glm::vec3 puv = p + u + v;
 glm::vec3 pvw = p + v + w;
 glm::vec3 puw = p + u + w;
 glm::vec3 puvw = p + u + v + w;

 // Front face
 vbo.addData(&p[0], sizeof(glm::vec3));
 vbo.addData(&pu[0], sizeof(glm::vec3));
 vbo.addData(&puw[0], sizeof(glm::vec3));
 vbo.addData(&p[0], sizeof(glm::vec3));
 vbo.addData(&puw[0], sizeof(glm::vec3));
 vbo.addData(&pw[0], sizeof(glm::vec3));
 
 // Back face
 vbo.addData(&puv[0], sizeof(glm::vec3));
 vbo.addData(&pv[0], sizeof(glm::vec3));
 vbo.addData(&pvw[0], sizeof(glm::vec3));
 vbo.addData(&puv[0], sizeof(glm::vec3));
 vbo.addData(&pvw[0], sizeof(glm::vec3));
 vbo.addData(&puvw[0], sizeof(glm::vec3));

 // Left face
 vbo.addData(&pv[0], sizeof(glm::vec3));
 vbo.addData(&p[0], sizeof(glm::vec3));
 vbo.addData(&pw[0], sizeof(glm::vec3));
 vbo.addData(&pv[0], sizeof(glm::vec3));
 vbo.addData(&pw[0], sizeof(glm::vec3));
 vbo.addData(&pvw[0], sizeof(glm::vec3));

 // Right face
 vbo.addData(&pu[0], sizeof(glm::vec3));
 vbo.addData(&puv[0], sizeof(glm::vec3));
 vbo.addData(&puvw[0], sizeof(glm::vec3));
 vbo.addData(&pu[0], sizeof(glm::vec3));
 vbo.addData(&puvw[0], sizeof(glm::vec3));
 vbo.addData(&puw[0], sizeof(glm::vec3));

 // Top face
 vbo.addData(&pw[0], sizeof(glm::vec3));
 vbo.addData(&puw[0], sizeof(glm::vec3));
 vbo.addData(&puvw[0], sizeof(glm::vec3));
 vbo.addData(&pw[0], sizeof(glm::vec3));
 vbo.addData(&puvw[0], sizeof(glm::vec3));
 vbo.addData(&pvw[0], sizeof(glm::vec3));

 // Bottom face
 vbo.addData(&pv[0], sizeof(glm::vec3));
 vbo.addData(&puv[0], sizeof(glm::vec3));
 vbo.addData(&pu[0], sizeof(glm::vec3));
 vbo.addData(&pv[0], sizeof(glm::vec3));
 vbo.addData(&pu[0], sizeof(glm::vec3));
 vbo.addData(&p[0], sizeof(glm::vec3));

 numVertices = 36;

 // create VBO
 vbo.createVBO();
 vbo.bindVBO();
 vbo.uploadDataToGPU(GL_STATIC_DRAW);

 // create a VAO
 glGenVertexArrays(1, &vao);
 glBindVertexArray(vao);
 glEnableVertexAttribArray(0);
 glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);

 isLoaded = true;
}