调用 glGenFramebuffers(） 时的 Segfault

我想在3D之上做一些2D，这样我就可以做一个像样的GUI。所以我创建了纹理等等。

我可以编译代码，它不会产生错误。 但是当我运行程序时，一切都很好，直到我称之为：

glGenFramebuffers(1, &fb);

然后出现：

error 139 segmentation fault (core dumped).

有人知道代码出了什么问题吗？

std::cout << "test1" << std::endl;
unsigned int fb;
glGenFramebuffers(1, &fb);
std::cout << "test2" << std::endl;
glBindRenderbuffer(GL_RENDERBUFFER, fb);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, renderTexture.getId(), 0);

显示"test1"文本，但不显示"test2"。

法典：

游戏.cpp

#include "game.h"
game::game(){
    SDL_Init(SDL_INIT_EVERYTHING);
    SDL_Surface* screen = SDL_SetVideoMode(1000, 600, 32, SDL_SWSURFACE|SDL_OPENGL);
    glClearColor(0.5, 0.5, 0.5, 1.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45, 1000.0/600.0, 1.0, 500.0);
    glMatrixMode(GL_MODELVIEW);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_TEXTURE_2D);
}
game::~game(){
    SDL_Quit();
}
void game::start(){
    Uint32 start;
    SDL_Event event;
    texture renderTexture = texture();
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 1000, 600, 0, GL_BGRA, GL_UNSIGNED_BYTE, 0);
    std::cerr << "test1" << std::endl;
    unsigned int fb;
    glGenFramebuffers(1, &fb);
    std::cerr << "test2" << std::endl;
    glBindRenderbuffer(GL_RENDERBUFFER, fb);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, renderTexture.getId(), 0);
    bool running = true;
    while (running){
        start = SDL_GetTicks();
        while (SDL_PollEvent(&event)){
            switch (event.type){
                case SDL_QUIT:
                    running = false;
                    break;
            }
        }
        update();
        show(fb);
        showMenu();
        SDL_GL_SwapBuffers();
        if (1000/30 > (SDL_GetTicks()-start)){
            SDL_Delay(1000/30 - (SDL_GetTicks()-start));
        }
    }
}
void game::update(){
}
void game::show(unsigned int fb){
    glBindFramebuffer(GL_FRAMEBUFFER, fb);
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
}
void game::showMenu(){
    bindWindowAsRenderTarget();
    glViewport(0, 0, 1000, 600);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0.0, 1000.0, 0.0, 600.0, -1.0, 1.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}
void game::bindWindowAsRenderTarget(){
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
    glViewport(0, 0, 1000, 600);
}

游戏.h

#ifndef GAME_H_INCLUDED
#define GAME_H_INCLUDED
#include <iostream>
#include <SDL/SDL.h>
#include <GL/glew.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include "texture.h"
class game{
    void update();
    void show(unsigned int fb);
    void showMenu();
    void bindWindowAsRenderTarget();
    public:
        game();
        ~game();
        void start();
};
#endif // GAME_H_INCLUDED

主.cpp

#include "game.h"
int main(int argc, char** argv){
    game g;
    g.start();
    return 0;
}

质地.cpp

#ifndef TEXTURE_H_INCLUDED
#define TEXTURE_H_INCLUDED
#include <SDL/SDL.h>
#include <GL/glew.h>
#include <GL/gl.h>
#include <GL/glu.h>
class texture{
    unsigned int id;
    public:
        texture();
        ~texture();
        void loadImage(const char* filename);
        unsigned int getId();
};
#endif // TEXTURE_H_INCLUDED

质地.cpp

#include "texture.h"
texture::texture(){
    glGenTextures(1, &id);
    glBindTexture(GL_TEXTURE_2D, id);
}
texture::~texture(){
    glDeleteTextures(1, &id);
}
void texture::loadImage(const char* filename){
    SDL_Surface* img = SDL_LoadBMP(filename);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img->w, img->h, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, img->pixels);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    SDL_FreeSurface(img);
}
unsigned int texture::getId(){
    return id;
}