c++ - 无法在 SDL2 (MAC M1) 中正确渲染三角形

Question

我正在尝试在我的 MAC (M1) 上使用 SDL2 渲染一个三角形，但是，我能够生成的三角形像素化太多，并且正在渲染不必要的像素。

输出:

我的代码:

int main(int argc, char *argv[])
{
    // returns zero on success else non-zero
    if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
        printf("error initializing SDL: %s\n", SDL_GetError());
    }
    SDL_Window* win = SDL_CreateWindow("GAME",
                                       SDL_WINDOWPOS_CENTERED,
                                       SDL_WINDOWPOS_CENTERED,
                                       900, 900, SDL_WINDOW_ALLOW_HIGHDPI);
    if(!win)
    {
        std::cout << "Failed to create window\n";
        return -1;
    }
    
    int *w_t = new int ();
    int *h_t = new int ();
    
    SDL_GetWindowSize(win,w_t,h_t);
    
    std::cout<<"width:"<<*w_t<<"height:"<<*h_t;
    
    SDL_Renderer* brush = SDL_CreateRenderer(win, -1, 0);
    
    SDL_SetRenderDrawColor(brush, 255, 0, 0, 0);
    SDL_Point a = {0,500};
    SDL_Point b = {800,500};
    SDL_Point c = {250,250};
    bool quit = false;
    SDL_Event e;
    while (!quit) {
        while (SDL_PollEvent(&e)) {
            if (e.type == SDL_QUIT) {
                quit = true;
            }
        }
        SDL_RenderDrawLine(brush, a.x, a.y, b.x, b.y);
        SDL_RenderDrawLine(brush, a.x, a.y, c.x, c.y);
        SDL_RenderDrawLine(brush, b.x, b.y, c.x, c.y);
        SDL_RenderPresent(brush);
    }

 
    return 0;
}

• 操作系统:macOS Monterey
• 集成开发环境:Xcode
• 编译器:Clang

Answer 1

尝试在绘制线条之前清除渲染器:

SDL_SetRenderDrawColor(brush, 0, 0, 0, SDL_ALPHA_OPAQUE);
SDL_RenderClear(brush);

SDL_SetRenderDrawColor(brush, 255, 0, 0, SDL_ALPHA_OPAQUE); 
SDL_RenderDrawLine(brush, a.x, a.y, b.x, b.y);
SDL_RenderDrawLine(brush, a.x, a.y, c.x, c.y);
SDL_RenderDrawLine(brush, b.x, b.y, c.x, c.y);
SDL_RenderPresent(brush);