OpenGL在以下教程之后没有渲染任何内容

我最近开始在youtube上关注TheCherno的OpenGL教程系列
这是我的代码：

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
struct ShaderProgramSource {
std::string VertexSource;
std::string FragmentSource;
};
static ShaderProgramSource ParseShader(const std::string& filepath) {
std::ifstream stream(filepath);
enum class ShaderType {
NONE = -1, VERTEX = 0, FRAGMENT = 1
};
std::string line;
std::stringstream ss[2];
ShaderType type = ShaderType::NONE;
while (getline(stream, line)) {
if (line.find("#shader") != std::string::npos) {
if (line.find("vertex") != std::string::npos)
type = ShaderType::VERTEX;
else if (line.find("fragment") != std::string::npos)
type = ShaderType::FRAGMENT;
} else {
ss[(int)type] << line << 'n';
}
}
return { ss[0].str(), ss[1].str() };
}
static unsigned int CompileShader(unsigned int type, const std::string& source) {
std::cout << "Compiling " << (type == GL_VERTEX_SHADER ? "vertex" : "fragment") << " shader..." << std::endl;
unsigned int id = glCreateShader(type);
const char* src = source.c_str();
glShaderSource(id, 1, &src, nullptr);
std::cout << glGetError() << std::endl;
glCompileShader(id);
std::cout << glGetError() << std::endl;
int result;
glGetShaderiv(id, GL_COMPILE_STATUS, &result);
std::cout << glGetError() << std::endl;
if (result == GL_FALSE) {
int length;
glGetShaderiv(id, GL_INFO_LOG_LENGTH, &length);
std::cout << glGetError() << std::endl;
char* message = (char*)alloca(length * sizeof(char));
glGetShaderInfoLog(id, length, &length, message);
std::cout << glGetError() << std::endl;
std::cout << "Failed to compile" << (type == GL_VERTEX_SHADER ? "vertex" : "fragment") << " shader!" << std::endl;
std::cout << message << std::endl;
glDeleteShader(id);
std::cout << glGetError() << std::endl;
return 0;
}
std::cout << "Successfully compiled " << (type == GL_VERTEX_SHADER ? "vertex" : "fragment") << " shader!" << std::endl << std::endl;
return id;
}
static unsigned int CreateShader(const std::string& vertexShader, const std::string& fragmentShader) {
std::cout << "Creating shader..." << std::endl << std::endl;

unsigned int program = glCreateProgram();
unsigned int vs = CompileShader(GL_VERTEX_SHADER, vertexShader);
unsigned int fs = CompileShader(GL_FRAGMENT_SHADER, fragmentShader);
glAttachShader(program, vs);
std::cout << glGetError() << std::endl;
std::cout << "Attached vertex shader" << std::endl;
glAttachShader(program, fs);
std::cout << glGetError() << std::endl;
std::cout << "Attached fragment shader" << std::endl;
glLinkProgram(program);
std::cout << glGetError() << std::endl;
glValidateProgram(program);
std::cout << glGetError() << std::endl;
std::cout << "Linked and validated program" << std::endl;
glDeleteShader(vs);
std::cout << glGetError() << std::endl;
std::cout << "Deleted vertex shader" << std::endl;
glDeleteShader(fs);
std::cout << glGetError() << std::endl;
std::cout << "Deleted fragment shader" << std::endl;
std::cout << "Succesfully created shader!" << std::endl << std::endl;
return program;
}
int main(void)
{
GLFWwindow* window;
/* Initialize the library */
if (!glfwInit())
return -1;
/* 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) {
std::cout << "Error!" << std::endl;
}
std::cout << glGetString(GL_VERSION) << std::endl;
float positions[6] = {
-0.5f, -0.5f,
0.0f,  0.5f,
0.5f, -0.5f
};
unsigned int buffer;
glGenBuffers(1, &buffer);
std::cout << glGetError() << std::endl;
glBindBuffer(GL_ARRAY_BUFFER, buffer);
std::cout << glGetError() << std::endl;
glBufferData(GL_ARRAY_BUFFER, 6*sizeof(float), positions, GL_STATIC_DRAW);
std::cout << glGetError() << std::endl;
glDisableVertexAttribArray(0);
std::cout << glGetError() << std::endl;
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(float)*2, 0);
std::cout << glGetError() << std::endl;
glBindBuffer(GL_ARRAY_BUFFER, 0);
std::cout << glGetError() << std::endl;

ShaderProgramSource source = ParseShader("res/shaders/Basic.shader");
std::cout << "VERTEX" << std::endl;
std::cout << source.VertexSource << std::endl;
std::cout << "FRAGMENT" << std::endl;
std::cout << source.FragmentSource << std::endl;
//unsigned int shader = CreateShader(vertexShader, fragmentShader);
///glUseProgram(shader);


// render loop
while (!glfwWindowShouldClose(window))
{
/* Render here */
glClear(GL_COLOR_BUFFER_BIT);
glDrawArrays(GL_TRIANGLES, 0, 3);
/* Swap front and back buffers */
glfwSwapBuffers(window);
/* Poll for and process events */
glfwPollEvents();
}
//glDeleteProgram(shader);
glfwTerminate();
return 0;
}

这是Basic.shader文件：

#shader vertex
#version 330 core  
layout(location = 0) in vec4 position;  
void main()  
{  
gl_Position = position;  
}
#shader fragment
#version 330 core  
layout(location = 0) out vec4 color;  
void main()  
{  
color = vec4(1.0, 0.0, 0.0, 1.0);  
}

我尝试过使用glGetError，但它没有输出任何错误。