SDL_PollEvent prevents render unless window moved or resized

Question

I have similar issue to this question, except I use SDL renderer instead of surface. I'm trying to render video using ffmpeg but it doesn't matter what I try to render, even simple SDL_Rect doesn't work. I see only black screen unless I move or resize window, then it immediately starts rendering. If I remove SDL_PollEvent it renders properly. I also tried using software renderer, it behaves the same way. Putting rendering into separate thread doesn't help either.

I'm on macOS with SDL2 installed via Homebrew.

SDL_Window *win = nullptr;
SDL_Renderer *renderer = nullptr;

SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO|SDL_INIT_TIMER|SDL_INIT_EVENTS);

win = SDL_CreateWindow("Demo", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, width, height, SDL_WINDOW_RESIZABLE|SDL_WINDOW_ALLOW_HIGHDPI);
renderer = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED);

while (true) {
    SDL_Event e;
    if (SDL_PollEvent(&e)) {
        if (e.type == SDL_QUIT) {
            break;
        }
    }

    // update texture data via ffmpeg
    // (code omitted)

    // render
    SDL_RenderClear(renderer);
    SDL_RenderCopy(renderer, video_texture, nullptr, nullptr);
    SDL_RenderPresent(renderer);
}

Answer 1

After some additional debugging I couldn't find any evidence to what's going on even after digging through SDL sources and looking at SDL_Window and SDL_Renderer structures in runtime. I am using Mojave Beta currently but I observed same behavior on High Sierra before. I tried to create renderer with Metal driver introduced in SDL 2.0.8 and it works properly now, and I observe no difference in SDL runtime structures compared to OpenGL which leads me to a suspicion that it's an OS issue. So I'd advise to use Metal renderer on Mac as a solution and just whenever possible. It's the only API supported by Apple after all.