Volume slider that adjusts how loud games are on a global level (#3240)

* Update config.cpp

* Update config.h

* Update sdl_audio.cpp

* Update settings_dialog.cpp

* Update settings_dialog.h

* Update settings_dialog.ui

* Update gui_settings.h

* Update audioout.cpp

* Update audioout.h

* Update settings_dialog.cpp

* remove leftover settings_dialog.ui

* Update settings_dialog.ui

---------

Co-authored-by: georgemoralis <giorgosmrls@gmail.com>

src/core/libraries/audio/audioout.cpp

@@ -523,9 +523,24 @@ s32 PS4_SYSV_ABI sceAudioOutSetVolume(s32 handle, s32 flag, s32* vol) {
         }
         port.impl->SetVolume(port.volume);
     }
+    AdjustVol();
     return ORBIS_OK;
 }
 
+void AdjustVol() {
+    if (audio == nullptr) {
+        return;
+    }
+
+    for (int i = 0; i < ports_out.size(); i++) {
+        std::unique_lock lock{ports_out[i].mutex};
+        if (!ports_out[i].IsOpen()) {
+            continue;
+        }
+        ports_out[i].impl->SetVolume(ports_out[i].volume);
+    }
+}
+
 int PS4_SYSV_ABI sceAudioOutSetVolumeDown() {
     LOG_ERROR(Lib_AudioOut, "(STUBBED) called");
     return ORBIS_OK;

src/core/libraries/audio/audioout.h

@@ -181,5 +181,6 @@ int PS4_SYSV_ABI sceAudioOutSystemControlSet();
 int PS4_SYSV_ABI sceAudioOutSparkControlSetEqCoef();
 int PS4_SYSV_ABI sceAudioOutSetSystemDebugState();
 
+void AdjustVol();
 void RegisterLib(Core::Loader::SymbolsResolver* sym);
 } // namespace Libraries::AudioOut

src/core/libraries/audio/sdl_audio.cpp

@@ -4,6 +4,7 @@
 #include <thread>
 #include <SDL3/SDL_audio.h>
 #include <SDL3/SDL_hints.h>
+#include <common/config.h>
 
 #include "common/logging/log.h"
 #include "core/libraries/audio/audioout.h"
@@ -41,6 +42,7 @@ public:
             stream = nullptr;
             return;
         }
+        SDL_SetAudioStreamGain(stream, Config::getVolumeSlider() / 100.0f);
     }
 
     ~SDLPortBackend() override {
@@ -77,7 +79,8 @@ public:
         }
         // SDL does not have per-channel volumes, for now just take the maximum of the channels.
         const auto vol = *std::ranges::max_element(ch_volumes);
-        if (!SDL_SetAudioStreamGain(stream, static_cast<float>(vol) / SCE_AUDIO_OUT_VOLUME_0DB)) {
+        if (!SDL_SetAudioStreamGain(stream, static_cast<float>(vol) / SCE_AUDIO_OUT_VOLUME_0DB *
+                                                Config::getVolumeSlider() / 100.0f)) {
             LOG_WARNING(Lib_AudioOut, "Failed to change SDL audio stream volume: {}",
                         SDL_GetError());
         }