c++ - SDL_WINDOWEVENT_SIZE_CHANGED 和 SDL_WINDOWEVENT_RESIZED 不工作？

Question

我正在尝试检测 SDL2 窗口的大小何时发生变化。但是 SDL_WINDOWEVENT_RESIZED 和 SDL_WINDOWEVENT_SIZE_CHANGED 都不起作用，至少在 MacOS 上是这样。这是我的代码:

SDL_Init(SDL_INIT_VIDEO);
SDL_Window *win = SDL_CreateWindow("", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 100, 100, SDL_WINDOW_RESIZABLE);
SDL_Renderer *ren = SDL_CreateRenderer(win, 0, 0);

bool running = true;
SDL_Event event;
while (running) {
    while(SDL_PollEvent(&event) != 0) {
        if(event.type == SDL_QUIT) {
            running = false;
        }

        if(event.type == SDL_WINDOWEVENT_SIZE_CHANGED) {
            return 3;
        }

        if(event.type == SDL_WINDOWEVENT_RESIZED) {
            return 4;
        }
    }

    SDL_RenderClear(ren);
}
SDL_DestroyRenderer(ren);
SDL_DestroyWindow(win);
SDL_Quit();
return 0;

运行程序和调整窗口大小时没有任何反应。我做错了什么还是错误？

编辑:我查阅了有关窗口事件的文档(https://wiki.libsdl.org/SDL_WindowEvent)。它说要写这样的东西:

event.window.type == SDL_WINDOWEVENT_SIZE_CHANGED 

但这也行不通。

Answer 1

SDL_WINDOWEVENT_* 不是事件类型，而是 SDL_WindowEventID .也就是说，如果您的 event.type 是 SDL_WINDOWEVENT，您可以访问 window union 字段以获取额外数据，包括 event，例如

while(SDL_PollEvent(&event)) {
    if(event.type == SDL_WINDOWEVENT) {
        if(event.window.event == SDL_WINDOWEVENT_SIZE_CHANGED) {
            // ...
        }
    }
}