Saving Fullscreen Preferences

1#include <iostream>
2#include <fstream>
3#include <SDL.h>
4
5enum class FullscreenMode {
6  Windowed,
7  Fullscreen,
8  BorderlessFullscreen
9};
10
11struct WindowSettings {
12  FullscreenMode Mode{FullscreenMode::Windowed};
13  int Width{800};
14  int Height{600};
15};
16
17void SaveSettings(
18  const WindowSettings& Settings) {
19  std::ofstream File{"window_settings.cfg"};
20  if (File) {
21    File << static_cast<int>(Settings.Mode)
22      << "\n"
23      << Settings.Width << "\n"
24      << Settings.Height;
25  }
26}
27
28WindowSettings LoadSettings() {
29  WindowSettings Settings;
30  std::ifstream File{"window_settings.cfg"};
31  if (File) {
32    int Mode;
33    File >> Mode;
34    Settings.Mode = static_cast<FullscreenMode>(
35      Mode);
36    File >> Settings.Width >> Settings.Height;
37  }
38  return Settings;
39}
40
41Uint32 GetSDLFullscreenFlags(FullscreenMode Mode) {
42  switch (Mode) {
43  case FullscreenMode::Fullscreen:
44    return SDL_WINDOW_FULLSCREEN;
45  case FullscreenMode::BorderlessFullscreen:
46    return SDL_WINDOW_FULLSCREEN_DESKTOP;
47  default:
48    return 0;
49  }
50}
51
52bool ApplyWindowSettings(
53  SDL_Window* Window,
54  const WindowSettings& Settings) {
55  // Store current display mode for fallback
56  SDL_DisplayMode CurrentMode;
57  SDL_GetWindowDisplayMode(
58    Window, &CurrentMode);
59
60  // Apply new size if windowed
61  if (Settings.Mode ==
62    FullscreenMode::Windowed) {
63    SDL_SetWindowSize(
64      Window,
65      Settings.Width,
66      Settings.Height
67    );
68  }
69
70  // Apply fullscreen mode
71  if (SDL_SetWindowFullscreen(
72    Window,
73    GetSDLFullscreenFlags(Settings.Mode)) < 0) {
74    // Revert on failure
75    SDL_SetWindowFullscreen(Window, 0);
76    SDL_SetWindowSize(
77      Window, CurrentMode.w, CurrentMode.h);
78    return false;
79  }
80
81  return true;
82}
83
84int main(int argc, char* argv[]) {
85  SDL_Init(SDL_INIT_VIDEO);
86
87  // Load saved settings
88  WindowSettings Settings{LoadSettings()};
89
90  // Create initial window
91  SDL_Window* Window{
92    SDL_CreateWindow(
93      "Game",
94      SDL_WINDOWPOS_UNDEFINED,
95      SDL_WINDOWPOS_UNDEFINED,
96      Settings.Width,
97      Settings.Height,
98      GetSDLFullscreenFlags(Settings.Mode)
99    )};
100
101  // Game loop would go here...
102
103  // Save settings before exit
104  SaveSettings(Settings);
105
106  SDL_DestroyWindow(Window);
107  SDL_Quit();
108  return 0;
109}