Volume setting

src/game_data.h

@@ -8,5 +8,6 @@ namespace game
   {
   public:
     MeasurementSystem measurementSystem{MeasurementSystem::METRIC};
+    int volume{100};
   };
 }

src/resource/audio.cpp

@@ -12,6 +12,12 @@ namespace game::resource
     return mixer;
   }
 
+  void Audio::set_gain(float gain)
+  {
+    auto mixer = mixer_get();
+    MIX_SetMasterGain(mixer, gain);
+  }
+
   void Audio::retain()
   {
     if (refCount) ++(*refCount);

src/resource/audio.h

@@ -10,7 +10,7 @@ namespace game::resource
     MIX_Audio* internal{nullptr};
     MIX_Track* track{nullptr};
     int* refCount{nullptr};
-    MIX_Mixer* mixer_get();
+    static MIX_Mixer* mixer_get();
     void unload();
     void retain();
     void release();
@@ -27,5 +27,6 @@ namespace game::resource
     void play(bool isLoop = false);
     void stop();
     bool is_playing() const;
+    static void set_gain(float vol);
   };
 }

src/resources.cpp

@@ -21,4 +21,8 @@ namespace game
   }
 
   void Resources::sound_play(audio::Type type) { audio[type].play(); }
+
+  void Resources::set_audio_gain(float vol) {
+    Audio::set_gain(vol);
+  }
 }

src/resources.h

@@ -124,5 +124,6 @@ namespace game
 
     Resources();
     void sound_play(audio::Type);
+    void set_audio_gain(float vol);
   };
 }

src/window/main_menu.cpp

@@ -6,6 +6,7 @@ namespace game::window
                         ImVec2 pos)
   {
     MeasurementSystem& measurementSystem = gameData.measurementSystem;
+    int& volume = gameData.volume;
 
     ImGui::SetNextWindowSize(size);
     ImGui::SetNextWindowPos(pos);
@@ -48,6 +49,13 @@ namespace game::window
           ImGui::RadioButton("Metric", (int*)&measurementSystem, MeasurementSystem::METRIC);
           ImGui::SameLine();
           ImGui::RadioButton("Imperial", (int*)&measurementSystem, MeasurementSystem::IMPERIAL);
+
+          ImGui::SeparatorText("Sound");
+          if (ImGui::SliderInt("Volume", (int*)&volume, 0, 100))
+          {
+            resources.set_audio_gain((float)volume / 100);
+          }
+
           ImGui::EndTabItem();
         }