void GeometryEngine::drawCubeGeometry(QOpenGLShaderProgram *program) {
    // Bind array buffer
    arrayBuf.bind();

    // Set position of vertices
    int posLocation = program->attributeLocation("a_position");
    program->enableAttributeArray(posLocation);
    program->setAttributeBuffer(posLocation, GL_FLOAT, 0, 3, sizeof(VertexData));

    // Set color of vertices
    int colorLocation = program->attributeLocation("a_color");
    program->enableAttributeArray(colorLocation);
    program->setAttributeBuffer(colorLocation, GL_FLOAT, sizeof(QVector3D), 3, sizeof(VertexData));

    // Bind index buffer
    indexBuf.bind();

    // Draw triangles
    glDrawElements(GL_TRIANGLES, indices, GL_UNSIGNED_INT, 0);

    // Release index buffer
    indexBuf.release();


    // Now I want to draw the contours of the same triangles, but this time as black lines ... ?

    // An attempt:
    QColor color;
    color.setRgb(0,0,0);
    program->setAttributeValue(colorLocation, color);

    indexBuf.bind();
    glDrawElements(GL_LINES, indices, GL_UNSIGNED_INT, 0);
    indexBuf.release();

    arrayBuf.release();
}