使用 SDL2 加载纹理的分段错误答案

【问题标题】：Segmentation fault loading texture with SDL2使用 SDL2 加载纹理的分段错误
【发布时间】：2014-05-11 13:40:38
【问题描述】：

我刚刚使用 SDL 1.2 完成了俄罗斯方块克隆，现在我正在尝试使用 SDL2 制作更好的版本。但是我遇到了分段错误，我不知道为什么。

这是 valgrind 报告：

==9471== Memcheck, a memory error detector
==9471== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==9471== Using Valgrind-3.9.0 and LibVEX; rerun with -h for copyright info
==9471== Command: ./tetris
==9471== 
==9471== Thread 2:
==9471== Invalid read of size 8
==9471==    at 0xB4B57A9: ??? (in /usr/lib/x86_64-linux-gnu/nvidia/current/libGL.so.319.82)
==9471==    by 0x4E8094E: ??? (in /usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0.1.0)
==9471==    by 0x4E799EA: SDL_CreateTexture (in /usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0.1.0)
==9471==    by 0x4E79C6D: SDL_CreateTextureFromSurface (in /usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0.1.0)
==9471==    by 0x401176: load_texture.3137.2439 
==9471==    by 0x401194: video_load_image.2436
==9471==    by 0x4011B6: block_image_load_all.2429
==9471==    by 0x4017BD: run_game_logic.2384
==9471==    by 0x541B061: start_thread (pthread_create.c:312)
==9471==    by 0x5715A3C: clone (clone.S:111)
==9471==  Address 0x8c0 is not stack'd, malloc'd or (recently) free'd
==9471== 
==9471== 
==9471== Process terminating with default action of signal 11 (SIGSEGV)
==9471==  Access not within mapped region at address 0x8C0
==9471==    at 0xB4B57A9: ??? (in /usr/lib/x86_64-linux-gnu/nvidia/current/libGL.so.319.82)
==9471==    by 0x4E8094E: ??? (in /usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0.1.0)
==9471==    by 0x4E799EA: SDL_CreateTexture (in /usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0.1.0)
==9471==    by 0x4E79C6D: SDL_CreateTextureFromSurface  (in /usr/lib/x86_64-linux-gnu/libSDL2-2.0.so.0.1.0)
==9471==    by 0x401176: load_texture.3137.2439
==9471==    by 0x401194: video_load_image.2436
==9471==    by 0x4011B6: block_image_load_all.2429
==9471==    by 0x4017BD: run_game_logic.2384
==9471==    by 0x541B061: start_thread (pthread_create.c:312)
==9471==    by 0x5715A3C: clone (clone.S:111)
==9471==  If you believe this happened as a result of a stack
==9471==  overflow in your program's main thread (unlikely but
==9471==  possible), you can try to increase the size of the
==9471==  main thread stack using the --main-stacksize= flag.
==9471==  The main thread stack size used in this run was 8388608.

以及功能：

SDL_Texture *video_load_image(const char *file)
{
    return load_texture(file);
}

static SDL_Texture *load_texture(const char *path)
{
    SDL_Surface *surface;
    SDL_Texture *texture;

    if((surface = SDL_LoadBMP(path)) == NULL){
        puts("invalid path");
        return NULL;
    }

    texture = SDL_CreateTextureFromSurface(renderer, surface);
    SDL_FreeSurface(surface);

    return texture;
}

char *image_path[BLOCK_COUNT] = {
    "img/block_dark_cyan32.bmp", "img/block_dark_red32.bmp",
    "img/block_dark_brown32.bmp", "img/block_dark_magenta32.bmp",
    "img/block_dark_gray32.bmp", "img/block_dark_green32.bmp",
    "img/block_dark_blue32.bmp", 
    "img/block_wall32.bmp", "img/block_empty32.bmp"
};

SDL_Texture *textures[BLOCK_COUNT];

int block_image_load_all(void)
{
    for(int i = 0; i < BLOCK_COUNT; ++i){
        if((textures[i] = video_load_image(image_path[i])) == NULL){
            while(i > 0)
                video_free_image(textures[--i]);

            return ERROR;
        }
    }

    return SUCCESS;
}

这里是什么导致分段错误？

更新：将渲染器切换到SDL_RENDERER_SOFTWARE 可以解决问题，但我想使用SDL_RENDERER_ACCELERATED

我不认为问题出在驱动程序上，因为我在另一个程序中成功使用了SDL_RENDERER_ACCELERATED。

【问题讨论】：

渲染器是否在纹理加载时完全初始化？您确定您的 OpenGL 驱动程序运行正常吗？至少使用glxinfo 和glxgears 对其进行测试。另外，valgrind 是内存调试器；如果发生崩溃，最好使用像gdb这样的普通调试器（但它与您的问题没有直接关系）
@keltar 我相信这与此代码或图像有关，因为 SDL_RENDERER_ACCELERATED 标志在另一个类似项目中正常工作。
@keltar 我按照您的建议对两者进行了测试，没有问题。图像格式可能是问题吗？我使用 gimp 创建了块并导出为 ARGB 32 位。
您不会在代码中显示BLOCK_COUNT 的定义 - 如果它超过image_path 中的字符串数，那么您可以使用空指针调用video_load_image。
@2013Asker 您如何制作完整的可编译的最小示例，包括您有问题的图像之一并将其上传到某个地方？可能有很多原因，但仅凭这些代码片段是不可能的。