OpenGL显示空白的白屏

我正在尝试将OpenGL函数抽象成自己的类。Vertexbuffer和IndexBuffer类工作。但是在尝试抽象Vertexarray类之后。它不起作用，我似乎无法锻炼什么问题。我正在提供3个文件主应用程序，缓冲类别文件和Vertexarray类文件。我遗漏了一些功能和一个文件，我认为这不是必要的

我尝试使用VS-2019调试。我在VS-2017中创建了这个项目，但已升级。直到glEnableVertexAttribArray都可以使用的所有内容，我已经检查了_ELEM的值，它们看起来正确。但是我看不到三角形。但是，当我尝试在原始功能中执行此操作时，它起作用

main.cpp：

#include "Buffer.h"
#include "VertexArray.h"
int main(void)
{
    GLFWwindow* window;
    /* Initialize the library */
    if (!glfwInit())
        return -1;
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, GL_TRUE);
    /* Create a windowed mode window and its OpenGL context */
    window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        return -1;
    }
    /* Make the window's context current */
    glfwMakeContextCurrent(window);
    if (glewInit() != GLEW_OK)
    {
        glfwTerminate();
        return -1;
    }
    glEnable(GL_DEBUG_CALLBACK_FUNCTION);
    glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);
    glDebugMessageCallback(GLErrLogger, nullptr);
    {
        float pos[] = {
             0.0f,  0.5f,
             0.5f, -0.5f,
            -0.5f, -0.5f
        };
        unsigned int indices[] = {
            0, 1, 2
        };
        // Some Shader stuff
        VertexBuffer vb(_BufferDataParams(pos));
        BufferLayout bLayout;
        bLayout.Push<GL_FLOAT, sizeof(GLfloat)>(2);
        //RefID va;
        //glGenVertexArrays(1, &va);
        //vb.BindSelf();
        //glBindVertexArray(va);
        VertexArray va(vb, bLayout);
        //glEnableVertexAttribArray(0);
        //glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), 0);
        IndexBuffer ib(_BufferDataParams(indices));
        glUseProgram(shader);
        GLint location = glGetUniformLocation(shader, "u_Color");
        if (location != -1)
                    glUniform4f(location, 0.2f, 0.3f, 0.8f, 1.0f);
        else
                    std::cerr << "u_Color doesn't exists.n";
        /* Loop until the user closes the window */
        while (!glfwWindowShouldClose(window))
        {
            /* Render here */
            glClear(GL_COLOR_BUFFER_BIT);
            glDrawElements(GL_TRIANGLES, ib.GetCount(), ib.GetDataType(), nullptr);
            /* Swap front and back buffers */
            glfwSwapBuffers(window);
            /* Poll for and process events */
            glfwPollEvents();
        }
        glDeleteProgram(shader);
    }
    glfwTerminate();
    return 0;
}

buffer.h：

#pragma once
#define _LenArr(_Arr) std::extent<decltype(_Arr)>::value
#define _BufferDataParams(_Arr) _Arr, sizeof(_Arr), _LenArr(_Arr)
using GLTYPE = unsigned int;
using Countable = unsigned int;
using LayoutElem = struct {
    GLTYPE Type;
    unsigned int Count;
    size_t ElemSize;
    GLTYPE Normalized;
};
struct BufferLayout
{
private:
    std::vector<LayoutElem> Layout;
    Countable Stride;
public:
    BufferLayout() : Stride(0)  {}
    template<GLTYPE _GL_Ty, size_t _ElemSize>
    void Push(Countable Count, GLTYPE normalized = GL_FALSE)
    {
        Layout.push_back({ _GL_Ty, Count, _ElemSize, normalized });
        Stride += Count * _ElemSize;
    }
    inline const std::vector<LayoutElem>& GetElements() const { return Layout; }
    inline Countable GetStride() const { return Stride; }
};
template <unsigned int TYPE, GLTYPE _DataType>
class Buffer
{
private:
    unsigned int mRefID;
    size_t m_Count;
    GLTYPE mDataType;
public:
    Buffer(const void* data, size_t size, size_t count,
        GLTYPE dataType = _DataType, unsigned int usage = GL_STATIC_DRAW)
        : mRefID(0), m_Count(count), mDataType(dataType)
    {
        glGenBuffers(1, &mRefID);
        glBindBuffer(TYPE, mRefID);
        glBufferData(TYPE, size, data, usage);
    }
    inline unsigned int GetRefID() const { return mRefID; }
    inline size_t GetCount() const { return m_Count; }
    inline GLTYPE GetDataType() const { return mDataType; }
    void SetData(const void* data, size_t size, size_t count,
        GLTYPE dataType = _DataType, unsigned int usage = GL_STATIC_DRAW)
    {
        glBindBuffer(TYPE, mRefID);
        glBufferData(TYPE, size, data, usage);
        m_Count = count;
        mDataType = dataType;
    }
    inline static void Bind(const Buffer& buf)
        { glBindBuffer(TYPE, buf.GetRefID()); }
    void BindSelf() const { Bind(*this); }
    inline static void Unbind() { glBindBuffer(TYPE, 0); }
    void Delete() const { glDeleteBuffers(1, &mRefID); }
    ~Buffer() { glDeleteBuffers(1, &mRefID);}
};
using VertexBuffer  = Buffer<GL_ARRAY_BUFFER, GL_FLOAT>;
using IndexBuffer   = Buffer<GL_ELEMENT_ARRAY_BUFFER, GL_UNSIGNED_INT>;

vertexarray.cpp：

#include "stdafx.h"
#include "VertexArray.h"
VertexArray::VertexArray()
    : mRefID(0)
{ glGenVertexArrays(1, &mRefID);}
void VertexArray::Bind(const VertexArray& vArr)
{ glBindVertexArray(vArr.GetRefID()); }
void VertexArray::BindSelf() const { Bind(*this); }
void VertexArray::AddBuffer(const VertexBuffer& vBuf, const BufferLayout& bufLayout)
{
    BindSelf();
    vBuf.BindSelf();
    const auto& Layout = bufLayout.GetElements();
    Countable i = 0;
    size_t offset = 0;
    for (LayoutElem _Elem : Layout)
    {
        std::cout << _Elem.Count << " " << _Elem.Type << " " <<
            _Elem.Normalized << " " << bufLayout.GetStride();
        glEnableVertexAttribArray(i);
        glVertexAttribPointer(i, _Elem.Count, _Elem.Type, _Elem.Normalized,
            bufLayout.GetStride(), (const void*)&offset);
        offset += _Elem.Count * _Elem.ElemSize;
        i++;
    }
}
VertexArray::VertexArray(const VertexBuffer& vBuf, const BufferLayout& bufLayout)
    : mRefID(0)
{
    glGenVertexArrays(1, &mRefID);
    AddBuffer(vBuf, bufLayout);
}
void VertexArray::Unbind() { glBindVertexArray(0); }
inline void VertexArray::Delete() const { glDeleteVertexArrays(1, &mRefID); }
VertexArray::~VertexArray() { Delete(); }

我希望看到一个带有蓝色的三角形。为了抽象工作。