OpenGL：运行 时出现分段错误（核心已转储）

Question

我正在用 C++ 和 OpenGL 编写游戏引擎，当我打开第一个测试时 window 我收到了这个问题：

Segmentation fault (core dumped)

编译没有报错，编译正常。问题出在我去打开 window.

如何复制：

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>

void framebuffer_size_callback(GLFWwindow* window, int width, int height);

void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}

int main()
{
  typedef void (*GL_GENBUFFERS) (GLsizei, GLuint*);
  GL_GENBUFFERS glGenBuffers = (GL_GENBUFFERS) glfwGetProcAddress("glGenBuffers");
  unsigned int buffer;
  glGenBuffers(1, &buffer);

  glfwInit();
  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
  GLFWwindow* window = glfwCreateWindow(800, 600, "BloodBunny", NULL, NULL);
  if (window == NULL)
  {
    std::cout << "Failed to create GLFW window" << std::endl;
    glfwTerminate();
    return -1;
  }
  glfwMakeContextCurrent(window);
  if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
  {
    std::cout << "Failed to initialize GLAD" << std::endl;
    return -1;
  }
  while(!glfwWindowShouldClose(window))
  {
    glfwSwapBuffers(window);
    glfwPollEvents();
  }
  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
  glViewport(0,0,800,600);
  glfwTerminate();
  return 0;
}

Answer 1

glfwGetProcAddress() 将仅（可能，取决于请求的名称和当前上下文的 GL 版本）return 可用，非 NULL function-pointers 如果GL 上下文是当前的。

使用 GLFW，你可以通过 glfwMakeContextCurrent() 使 window 的上下文成为当前上下文，所以如果你真的想获取你自己的指向 glGenBuffers() 的指针，你需要移动 glfwGetProcAddress() 在 成功后 调用 glfwMakeContextCurrent():

...
glfwMakeContextCurrent(window);
...
typedef void (*GL_GENBUFFERS) (GLsizei, GLuint*);
GL_GENBUFFERS glGenBuffers = (GL_GENBUFFERS) glfwGetProcAddress("glGenBuffers");
unsigned int buffer;
glGenBuffers(1, &buffer);
...

...尽管老实说没有什么意义，因为您在 glfwMakeContextCurrent() 之后立即调用 gladLoadGLLoader()，这将在全局范围内自行填充一个完全可用的 glGenBuffers() 指针。