在类中渲染OpenGL对象

我正在尝试学习现代OpenGL，并为各种基元类型(如立方体、球体等)创建类。不过，我遇到了一个问题，即我的立方体类在其Draw()函数中没有渲染任何内容，但如果我将其全部移到main()函数中，它会正常工作。

以下是cube.cpp的代码：

#include "cube.h"
#include <iostream>
GLuint Cube::indexArr[36] = {
0, 1, 2, // front face
2, 3, 1,
4, 5, 6,
6, 7, 4,
7, 3, 0,
0, 4, 7,
6, 2, 1,
1, 5, 6,
0, 1, 5,
5, 4, 0,
3, 2, 6,
6, 7, 3
};
bool    Cube::cubeSetUp = false;
GLuint  Cube::cubeVBO = 0;
GLuint  Cube::cubeVAO = 0;
GLuint  Cube::cubeEBO = 0;
Cube::Cube()
{
if (!cubeSetUp)
SetUpCube();
//define the 8 vertices that make up a cube
objectVerts = new GLfloat[24] {
-0.5f, -0.5f, -0.5f, // front bottom left  0
0.5f, -0.5f, -0.5f, // front bottom right 1
0.5f,  0.5f, -0.5f, // front top right    2
-0.5f,  0.5f, -0.5f, // front top left     3
-0.5f, -0.5f, 0.5f, // back bottom left   4
0.5f, -0.5f, 0.5f, // back bottom right  5
0.5f,  0.5f, 0.5f, // back top right     6
-0.5f,  0.5f, 0.5f  // back top left      7
};
}
void Cube::Draw()
{
glBindVertexArray(cubeVAO);
//GLfloat modelMatrix[16];
//transform.affine.ConvertToOpenGLMatrix(modelMatrix);
//glUniformMatrix4fv(modelMatrixLoc, 1, GL_FALSE, modelMatrix);
glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_INT, 0);   
glBindVertexArray(0);
}

void Cube::SetUpCube()
{
cubeSetUp = true;
glGenVertexArrays(1, &cubeVAO);
glGenBuffers(1, &cubeVBO);
glGenBuffers(1, &cubeEBO);
glBindVertexArray(cubeVAO);
glBindBuffer(GL_ARRAY_BUFFER, cubeVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(objectVerts), objectVerts, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, cubeEBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indexArr), indexArr, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}

cube.h:的代码

#ifndef __CUBE__H_
#define __CUBE__H_
#include "scene_object.h"
class Cube : public SceneObject
{
public:
/***************
* Constructor *
***************/
Cube();
/***********************
* Overloaded Function *
***********************/
void Draw();
private:
static GLuint  indexArr[36];
static bool    cubeSetUp;
static GLuint  cubeVBO, cubeVAO, cubeEBO;
void SetUpCube();
};
#endif

我做错什么了吗？OpenGL是否不同意使用静态数组作为索引数组？我试着去掉元素缓冲区对象，只使用glDrawArrays(...)，但它也不起作用。如果需要的话，我也可以提供main的代码。

此外，顶点着色器没有执行任何操作。它只接收顶点信息并将其提供给gl_Position。

谢谢你的帮助。

main.cpp:的代码

#define GLEW_STATIC
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include <fstream>
#include <string>
#include "shader.h"
#include "cube.h"
#include "camera.h"
using namespace std;
int main(int argc, char* argv[])
{
if (argc != 3)
{
cout << "Incorrect number of arguments!" << endl;
cout << "Usage: [executable] vertexShader fragmentShader" << endl;
return -1;
}
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
GLFWwindow* window = glfwCreateWindow(800, 600, "Scene Description Language Generator", nullptr, nullptr);
if (window == nullptr)
{
std::cout << "Failed to create the GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glewExperimental = GL_TRUE;
if (glewInit() != GLEW_OK)
{
std::cout << "Failed to initialize GLEW" << std::endl;
return -1;
}
glEnable(GL_DEPTH_TEST);
int width, height;
glfwGetFramebufferSize(window, &width, &height);
glViewport(0, 0, width, height);
Shader shader(argv[1], argv[2]);
Cube c;
GLuint modelMat = glGetUniformLocation(shader.GetProgram(), "model");
c.SetModelMatrixLoc(modelMat);
while (!glfwWindowShouldClose(window))
{
glfwPollEvents();
glClearColor(0.2f, 0.3f, 0.3f, 1);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
shader.Use();
c.Draw();
glfwSwapBuffers(window);
}
glfwTerminate();
return 0;
}

编辑：添加了main.cpp和cube.h的代码，以防有价值。