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SDL_Texture导致所有内容呈现黑色

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我已经在SDL中开发了一个相当大的应用程序一段时间,最近发现了一个奇怪的错误;每当窗口关闭时,另一个窗口上的所有内容都将呈现完全黑色 . 当我画一条红线时,它会是黑色的,当我画一个SDL_Texture时,它会画一个黑色矩形来代替图像 .

过了一会儿,我设法通过从头开始制作应用程序的简化版本来重新创建问题 . 该程序包括一个窗口类,用于存储窗口,其渲染器和SDL_Texture . 窗口类还包括一个渲染函数,用于将事物渲染到其窗口,包括SDL_Texture . 还有一个函数允许每个窗口对象处理SDL事件,例如窗口被关闭 . 窗口关闭时,窗口,渲染器和纹理都被破坏 .

class Window {
    SDL_Window *window;
    SDL_Renderer *renderer;
    Uint32 windowID;

    SDL_Texture *texture;

    void cleanup() {
        SDL_DestroyWindow(window);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyTexture(texture);
    }

    bool running = true;
public:

    void init() {

        window = SDL_CreateWindow("Window", 50, 50, 721, 558, SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE);
        renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
        windowID = SDL_GetWindowID(window);
        SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND);

        // load texture
        SDL_Surface* loadedSurface = IMG_Load("picture.png");
        texture = SDL_CreateTextureFromSurface(renderer, loadedSurface);
        SDL_FreeSurface(loadedSurface);

    }

    bool isRunning() {
        return running;
    }

    void render() {
        // clear the screen with a green color
        SDL_SetRenderDrawColor(renderer, 0x00, 0xFF, 0x00, 0xFF);
        SDL_RenderClear(renderer);

        // create a rectangle for drawing things
        SDL_Rect rect = {0, 0, 100, 100};

        // draw a red rectangle
        SDL_SetRenderDrawColor(renderer, 0xFF, 0x00, 0x00, 0xFF);
        SDL_RenderFillRect(renderer, &rect);

        // draw the texture/image on top of the rectangle
        if (SDL_RenderCopy(renderer, texture, NULL, &rect) < 0) {
            printf("Unable to render texture! Error: %s\n", SDL_GetError());
        }



        SDL_RenderPresent(renderer);
    }

    void events(SDL_Event &e) {
        if (e.window.windowID == windowID && e.window.event == SDL_WINDOWEVENT_CLOSE) {
            running = false;
            cleanup();
        }
    }
};

主要功能一次管理多个窗口,并分别为每个窗口提供SDL事件:

int main(int argc, const char * argv[]) {

    if (SDL_Init(SDL_INIT_VIDEO) < 0) { // initialize SDL and IMG
        printf("SDL could not initialize! Error: %s\n", SDL_GetError());
    } else if (!(IMG_Init(IMG_INIT_PNG) & IMG_INIT_PNG)) {
        printf("SDL_image could not initialize! Error: %s\n", IMG_GetError());
    } else {
        std::vector<Window*> windows; // vector of window objects

        // add window objects to the vector
        windows.push_back(new Window());
        windows.push_back(new Window());
        windows.push_back(new Window());
        windows.push_back(new Window());

        // initialize all windows
        for (int i = 0; i < windows.size(); i++) {
            windows[i]->init();
        }

        // game loop
        bool loop = true;
        while (loop) {
            SDL_Delay(50); // delay between each frame

            // render all windows
            for (int i = 0; i < windows.size(); i++) {
                windows[i]->render();
            }

            // handle new events
            SDL_Event e;
            while (SDL_PollEvent(&e)) {

                // loop backward through windows
                // in case one of them has to be
                // removed from the vector
                for (unsigned long i = windows.size(); i-- > 0;) {
                    if (windows[i]->isRunning()) {
                        windows[i]->events(e);
                    } else {
                        // delete a window if it has been closed
                        delete windows[i];
                        windows.erase(windows.begin() + i);
                    }
                }
            }

            if (windows.empty()) { // if all windows are closed,
                loop = false;      // stop the loop
            }
        }

    }

    return 0;
}

现在我已经展示了我的代码,我将更详细地解释这个问题 . 程序启动时,会创建四个窗口对象,每个窗口都显示在屏幕上 . 每个窗口都可以正确渲染,PNG图像覆盖在红色矩形的顶部 . 第四个窗口或最后一个要初始化的窗口只会呈现颜色为黑色 after any other window is closed 的图像,矩形和线条等内容 . 唯一会以不同颜色呈现的是 SDL_RenderClear ,我在上面的代码中使用它来渲染绿色背景,它暴露出黑色图像和矩形形状 .

我已经测试过以确保在出现此问题后纹理,渲染器和窗口仍然有效,并且没有错误 .

我至少想找到导致问题的原因以及是否有任何可能的解决方案 .

1 回答

  • 2

    当渲染器还活着时,你不应该销毁窗口 . 尝试以相反的顺序执行 cleanup() 内的方法 .

    void cleanup()
    {
        SDL_DestroyTexture(texture);
        SDL_DestroyRenderer(renderer);
        SDL_DestroyWindow(window);
    }
    

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