white background

void set_background(int r, int g, int b) {
    r = r % 256;
    g = g % 256;
    b = b % 256;
    if (r < 0) {
        r = 0;
    }
    if (g < 0) {
        g = 0;
    }
    if (b < 0) {
        b = 0;
    }
    std::cout << "r=" << r << " g=" << g << " b=" << b << "\n";
    SDL_FillRect(screen, 0, SDL_MapRGB(screen->format,r,g,b));
}