为什么glDrawElements不渲染我的三角形

我一直在关注youtube上BennyBox的3D游戏引擎教程系列。这个系列是用java完成的，由于计算速度的原因，我喜欢c++，我一直遵循教程直到第15节，他开始使用glDrawElements而不是glDrawArrays。到目前为止，在教程中，我一直很好地将他的java代码转换为c++，但现在我可以绘制任何东西，而且opengl没有给我任何错误。我几乎可以肯定，问题是为opengl缓冲数据，或者告诉opengl如何缓冲数据。这是我的密码。

mainGame.cpp:

init:

glClearColor(0.1f, 0.0f, 0.5f, 0.0f);
glFrontFace(GL_CW);
glCullFace(GL_BACK);
glEnable(GL_CULL_FACE);
glEnable(GL_DEPTH_TEST);
glEnable(GL_FRAMEBUFFER_SRGB);
vector<Vertex> vertices;
vertices.push_back(glm::vec3(-1, 1, 0));
vertices.push_back(glm::vec3(0, -0.5f, 0));
vertices.push_back(glm::vec3(-1, -1, 0));
vertices.push_back(glm::vec3(1, 1, 0));
vertices.push_back(glm::vec3(1, -1, 0));
vertices.push_back(glm::vec3(0, 0.5, 0));
vector<unsigned short> indices;
indices.push_back(0);
indices.push_back(1);
indices.push_back(2);
indices.push_back(3);
indices.push_back(4);
indices.push_back(5);
mesh.meshInit();
mesh.addVerticies(vertices, indices);
mesh.draw();

gameRoop:

    while (_gameState != GameState::EXIT) {
        processInput();
        updateScene();
        drawScene();
        if (_TEST)
        {
            GLenum err;
            while ((err = glGetError()) != GL_NO_ERROR) {
                cout << "OpenGL error: " << err << endl;
            }
        }
    }

processInput（）目前与opengl绘图无关，updateScene（）只会清除屏幕并更新变换对象，但这不是问题所在。我之所以知道，是因为我试着把那个部分注释掉了，opengl仍然没有渲染/绘制任何东西。

drawScene：

shader.bind();
shader.setUniform("translation", transform.getTransformation());
mesh.draw();
SDL_GL_SwapWindow(_window);

以下是mesh类的函数，我认为我没有发送正确的信息。

mesh.cpp:

void Mesh::meshInit()
{
    glGenVertexArrays(1, &VAO);
    glBindVertexArray(VAO);
    glGenBuffers(1, &IBO);
    glGenBuffers(1, &VBO);
}
void Mesh::addVerticies(vector<Vertex> vertices, vector<unsigned short> indices)
{
    _indices = &indices[0];
    _vSize = vertices.size() * sizeof(float);
    _iSize = indices.size() * sizeof(unsigned short);
    if (_TEST) {
        cout << "size of verticies: " << _vSize << endl;
        cout << "size of indices: " << _iSize << endl;
        cout << "number of verticies: " << vertices.size() << endl;
        cout << "number of indices: " << indices.size() << endl;
        for (int i = 0; i < vertices.size() ; i++)
        {
            cout << vertices[i].getPos().x << " ";
            cout << vertices[i].getPos().y << " ";
            cout << vertices[i].getPos().z << " ";
            cout << "n";
        }
    }    
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, _vSize, &vertices[0], GL_STATIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, _iSize, &indices[0], GL_STATIC_DRAW);
}
int vertexAtribStride = Vertex::SIZE * sizeof(float);
void Mesh::draw()
{
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, vertexAtribStride, 0);
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IBO);
    glDrawElements(GL_TRIANGLES, _iSize, GL_INT, _indices);
    glDisableVertexAttribArray(0);
}