Save and Restore Brightness Settings

1#include <SDL.h>
2#include <filesystem>
3#include <fstream>
4#include <iostream>
5
6class BrightnessSettings {
7  SDL_Window* Window;
8  std::string SettingsPath;
9  float DefaultBrightness{1.0f};
10
11  struct Settings {
12    float Brightness{1.0f};
13    float GammaRed{1.0f};
14    float GammaGreen{1.0f};
15    float GammaBlue{1.0f};
16  } Current;
17
18public:
19  BrightnessSettings(
20    SDL_Window* W,const std::string& SavePath
21  ) : Window{W},
22      SettingsPath{SavePath + "/display.cfg"} {
23    LoadSettings();
24    ApplySettings();
25  }
26
27  void SaveSettings() {
28    try {
29      // Ensure directory exists
30      std::filesystem::create_directories(
31        std::filesystem::path{SettingsPath}.
32        parent_path());
33
34      std::ofstream File{
35        SettingsPath, std::ios::binary};
36      if (!File) {
37        std::cout <<
38          "Failed to save settings\n";
39        return;
40      }
41
42      File.write(
43        reinterpret_cast<char*>(&Current),
44        sizeof(Settings));
45
46      std::cout << "Settings saved\n";
47    }
48    catch (const std::exception& E) {
49      std::cout << "Error saving settings: "
50        << E.what() << '\n';
51    }
52  }
53
54  void SetBrightness(float NewBrightness) {
55    Current.Brightness = NewBrightness;
56    SDL_SetWindowBrightness(
57      Window, NewBrightness);
58  }
59
60  void SetGamma(float Red, float Green,
61                float Blue) {
62    Current.GammaRed = Red;
63    Current.GammaGreen = Green;
64    Current.GammaBlue = Blue;
65
66    Uint16 RedRamp[256];
67    Uint16 GreenRamp[256];
68    Uint16 BlueRamp[256];
69
70    SDL_CalculateGammaRamp(Red, RedRamp);
71    SDL_CalculateGammaRamp(Green, GreenRamp);
72    SDL_CalculateGammaRamp(Blue, BlueRamp);
73
74    SDL_SetWindowGammaRamp(
75      Window, RedRamp, GreenRamp, BlueRamp);
76  }
77
78private:
79  void LoadSettings() {
80    try {
81      std::ifstream File{
82        SettingsPath, std::ios::binary};
83      if (!File) {
84        std::cout << "Using default settings\n";
85        return;
86      }
87
88      File.read(
89        reinterpret_cast<char*>(&Current),
90        sizeof(Settings));
91
92      std::cout << "Settings loaded\n";
93    }
94    catch (const std::exception& E) {
95      std::cout << "Error loading settings: "
96        << E.what() << '\n';
97      Current = Settings{}; // Use defaults
98    }
99  }
100
101  void ApplySettings() {
102    SetBrightness(Current.Brightness);
103    SetGamma(Current.GammaRed,
104             Current.GammaGreen,
105             Current.GammaBlue);
106  }
107};
108
109int main() {
110  SDL_Init(SDL_INIT_VIDEO);
111
112  SDL_Window* Window{
113    SDL_CreateWindow("Settings Demo",
114                     SDL_WINDOWPOS_UNDEFINED,
115                     SDL_WINDOWPOS_UNDEFINED,
116                     800, 600,
117                     SDL_WINDOW_SHOWN)};
118
119  BrightnessSettings Settings{
120    Window, "./saves"};
121
122  // Simulate user changing settings
123  Settings.SetBrightness(1.5f);
124  Settings.SetGamma(1.1f, 1.0f, 0.9f);
125
126  // Save changes
127  Settings.SaveSettings();
128
129  SDL_DestroyWindow(Window);
130  SDL_Quit();
131  return 0;
132}