config: Add present mode option. (#3502)

* config: Add present mode option.

* settings_dialog: Add details for present modes.

src/common/config.cpp

@@ -79,6 +79,7 @@ static bool shouldPatchShaders = false;
 static u32 vblankDivider = 1;
 static bool isFullscreen = false;
 static std::string fullscreenMode = "Windowed";
+static std::string presentMode = "Mailbox";
 static bool isHDRAllowed = false;
 
 // Vulkan
@@ -194,6 +195,10 @@ std::string getFullscreenMode() {
     return fullscreenMode;
 }
 
+std::string getPresentMode() {
+    return presentMode;
+}
+
 bool getisTrophyPopupDisabled() {
     return isTrophyPopupDisabled;
 }
@@ -466,6 +471,10 @@ void setFullscreenMode(std::string mode) {
     fullscreenMode = mode;
 }
 
+void setPresentMode(std::string mode) {
+    presentMode = mode;
+}
+
 void setisTrophyPopupDisabled(bool disable) {
     isTrophyPopupDisabled = disable;
 }
@@ -726,6 +735,7 @@ void load(const std::filesystem::path& path) {
         vblankDivider = toml::find_or<int>(gpu, "vblankDivider", vblankDivider);
         isFullscreen = toml::find_or<bool>(gpu, "Fullscreen", isFullscreen);
         fullscreenMode = toml::find_or<std::string>(gpu, "FullscreenMode", fullscreenMode);
+        presentMode = toml::find_or<std::string>(gpu, "presentMode", presentMode);
         isHDRAllowed = toml::find_or<bool>(gpu, "allowHDR", isHDRAllowed);
     }
 
@@ -894,6 +904,7 @@ void save(const std::filesystem::path& path) {
     data["GPU"]["vblankDivider"] = vblankDivider;
     data["GPU"]["Fullscreen"] = isFullscreen;
     data["GPU"]["FullscreenMode"] = fullscreenMode;
+    data["GPU"]["presentMode"] = presentMode;
     data["GPU"]["allowHDR"] = isHDRAllowed;
     data["Vulkan"]["gpuId"] = gpuId;
     data["Vulkan"]["validation"] = vkValidation;
@@ -1003,6 +1014,7 @@ void setDefaultValues() {
     vblankDivider = 1;
     isFullscreen = false;
     fullscreenMode = "Windowed";
+    presentMode = "Mailbox";
     isHDRAllowed = false;
 
     // Vulkan

src/common/config.h

@@ -27,6 +27,8 @@ bool getIsFullscreen();
 void setIsFullscreen(bool enable);
 std::string getFullscreenMode();
 void setFullscreenMode(std::string mode);
+std::string getPresentMode();
+void setPresentMode(std::string mode);
 u32 getWindowWidth();
 u32 getWindowHeight();
 void setWindowWidth(u32 width);

src/qt_gui/settings_dialog.cpp

@@ -67,6 +67,7 @@ const QVector<int> languageIndexes = {21, 23, 14, 6, 18, 1, 12, 22, 2, 4,  25, 2
 QMap<QString, QString> channelMap;
 QMap<QString, QString> logTypeMap;
 QMap<QString, QString> screenModeMap;
+QMap<QString, QString> presentModeMap;
 QMap<QString, QString> chooseHomeTabMap;
 QMap<QString, QString> micMap;
 
@@ -93,6 +94,9 @@ SettingsDialog::SettingsDialog(std::shared_ptr<gui_settings> gui_settings,
     screenModeMap = {{tr("Fullscreen (Borderless)"), "Fullscreen (Borderless)"},
                      {tr("Windowed"), "Windowed"},
                      {tr("Fullscreen"), "Fullscreen"}};
+    presentModeMap = {{tr("Mailbox (Vsync)"), "Mailbox"},
+                      {tr("Fifo (Vsync)"), "Fifo"},
+                      {tr("Immediate (No Vsync)"), "Immediate"}};
     chooseHomeTabMap = {{tr("General"), "General"},   {tr("GUI"), "GUI"},
                         {tr("Graphics"), "Graphics"}, {tr("User"), "User"},
                         {tr("Input"), "Input"},       {tr("Paths"), "Paths"},
@@ -414,6 +418,7 @@ SettingsDialog::SettingsDialog(std::shared_ptr<gui_settings> gui_settings,
         // Graphics
         ui->graphicsAdapterGroupBox->installEventFilter(this);
         ui->windowSizeGroupBox->installEventFilter(this);
+        ui->presentModeGroupBox->installEventFilter(this);
         ui->heightDivider->installEventFilter(this);
         ui->dumpShadersCheckBox->installEventFilter(this);
         ui->nullGpuCheckBox->installEventFilter(this);
@@ -540,6 +545,9 @@ void SettingsDialog::LoadValuesFromConfig() {
     QString translatedText_FullscreenMode =
         screenModeMap.key(QString::fromStdString(Config::getFullscreenMode()));
     ui->displayModeComboBox->setCurrentText(translatedText_FullscreenMode);
+    QString translatedText_PresentMode =
+        presentModeMap.key(QString::fromStdString(Config::getPresentMode()));
+    ui->presentModeComboBox->setCurrentText(translatedText_PresentMode);
     ui->gameSizeCheckBox->setChecked(toml::find_or<bool>(data, "GUI", "loadGameSizeEnabled", true));
     ui->showSplashCheckBox->setChecked(toml::find_or<bool>(data, "General", "showSplash", false));
     QString translatedText_logType = logTypeMap.key(QString::fromStdString(Config::getLogType()));
@@ -746,6 +754,11 @@ void SettingsDialog::updateNoteTextEdit(const QString& elementName) {
     // Graphics
     if (elementName == "graphicsAdapterGroupBox") {
         text = tr("Graphics Device:\\nOn multiple GPU systems, select the GPU the emulator will use from the drop down list,\\nor select \"Auto Select\" to automatically determine it.");
+    } else if (elementName == "presentModeGroupBox") {
+        text = tr("Present Mode:\\nConfigures how video output will be presented to your screen.\\n\\n"
+                  "Mailbox: Frames synchronize with your screen's refresh rate. New frames will replace any pending frames. Reduces latency but may skip frames if running behind.\\n"
+                  "Fifo: Frames synchronize with your screen's refresh rate. New frames will be queued behind pending frames. Ensures all frames are presented but may increase latency.\\n"
+                  "Immediate: Frames immediately present to your screen when ready. May result in tearing.");
     } else if (elementName == "windowSizeGroupBox") {
         text = tr("Width/Height:\\nSets the size of the emulator window at launch, which can be resized during gameplay.\\nThis is different from the in-game resolution.");
     } else if (elementName == "heightDivider") {
@@ -834,6 +847,8 @@ void SettingsDialog::UpdateSettings() {
                             "Windowed");
     Config::setFullscreenMode(
         screenModeMap.value(ui->displayModeComboBox->currentText()).toStdString());
+    Config::setPresentMode(
+        presentModeMap.value(ui->presentModeComboBox->currentText()).toStdString());
     Config::setIsMotionControlsEnabled(ui->motionControlsCheckBox->isChecked());
     Config::setBackgroundControllerInput(ui->backgroundControllerCheckBox->isChecked());
     Config::setisTrophyPopupDisabled(ui->disableTrophycheckBox->isChecked());

src/qt_gui/settings_dialog.ui

@@ -1096,6 +1096,40 @@
                  </layout>
                 </widget>
                </item>
+               <item>
+                <widget class="QGroupBox" name="presentModeGroupBox">
+                 <property name="title">
+                  <string>Present Mode</string>
+                 </property>
+                 <layout class="QVBoxLayout" name="presentModeLayout">
+                  <item>
+                   <widget class="QComboBox" name="presentModeComboBox">
+                    <property name="sizePolicy">
+                     <sizepolicy hsizetype="Expanding" vsizetype="Fixed">
+                      <horstretch>0</horstretch>
+                      <verstretch>0</verstretch>
+                     </sizepolicy>
+                    </property>
+                    <item>
+                     <property name="text">
+                      <string>Mailbox (Vsync)</string>
+                     </property>
+                    </item>
+                    <item>
+                     <property name="text">
+                      <string>Fifo (Vsync)</string>
+                     </property>
+                    </item>
+                    <item>
+                     <property name="text">
+                      <string>Immediate (No Vsync)</string>
+                     </property>
+                    </item>
+                   </widget>
+                  </item>
+                 </layout>
+                </widget>
+               </item>
                <item>
                 <layout class="QHBoxLayout" name="windowSizeLayout">
                  <item>

src/video_core/renderer_vulkan/vk_swapchain.cpp

@@ -21,6 +21,7 @@ static constexpr vk::SurfaceFormatKHR SURFACE_FORMAT_HDR = {
 Swapchain::Swapchain(const Instance& instance_, const Frontend::WindowSDL& window_)
     : instance{instance_}, window{window_}, surface{CreateSurface(instance.GetInstance(), window)} {
     FindPresentFormat();
+    FindPresentMode();
 
     Create(window.GetWidth(), window.GetHeight());
     ImGui::Core::Initialize(instance, window, image_count, surface_format.format);
@@ -45,20 +46,6 @@ void Swapchain::Create(u32 width_, u32 height_) {
         instance.GetPresentQueueFamilyIndex(),
     };
 
-    const auto [modes_result, modes] =
-        instance.GetPhysicalDevice().getSurfacePresentModesKHR(surface);
-    const auto find_mode = [&modes_result, &modes](vk::PresentModeKHR requested) {
-        if (modes_result != vk::Result::eSuccess) {
-            return false;
-        }
-        const auto it =
-            std::find_if(modes.begin(), modes.end(),
-                         [&requested](vk::PresentModeKHR mode) { return mode == requested; });
-
-        return it != modes.cend();
-    };
-    const bool has_mailbox = find_mode(vk::PresentModeKHR::eMailbox);
-
     const bool exclusive = queue_family_indices[0] == queue_family_indices[1];
     const u32 queue_family_indices_count = exclusive ? 1u : 2u;
     const vk::SharingMode sharing_mode =
@@ -78,7 +65,7 @@ void Swapchain::Create(u32 width_, u32 height_) {
         .pQueueFamilyIndices = queue_family_indices.data(),
         .preTransform = transform,
         .compositeAlpha = composite_alpha,
-        .presentMode = has_mailbox ? vk::PresentModeKHR::eMailbox : vk::PresentModeKHR::eImmediate,
+        .presentMode = present_mode,
         .clipped = true,
         .oldSwapchain = nullptr,
     };
@@ -202,6 +189,38 @@ void Swapchain::FindPresentFormat() {
     UNREACHABLE_MSG("Unable to find required swapchain format!");
 }
 
+void Swapchain::FindPresentMode() {
+    const auto [modes_result, modes] =
+        instance.GetPhysicalDevice().getSurfacePresentModesKHR(surface);
+    if (modes_result != vk::Result::eSuccess) {
+        LOG_ERROR(Render, "Failed to query available present modes, falling back to Fifo as "
+                          "guaranteed supported option.");
+        present_mode = vk::PresentModeKHR::eFifo;
+        return;
+    }
+
+    const auto requested_mode = Config::getPresentMode();
+    if (requested_mode == "Mailbox") {
+        present_mode = vk::PresentModeKHR::eMailbox;
+    } else if (requested_mode == "Fifo") {
+        present_mode = vk::PresentModeKHR::eFifo;
+    } else if (requested_mode == "Immediate") {
+        present_mode = vk::PresentModeKHR::eImmediate;
+    } else {
+        LOG_ERROR(Render_Vulkan, "Unknown present mode {}, defaulting to Mailbox.",
+                  Config::getPresentMode());
+        present_mode = vk::PresentModeKHR::eMailbox;
+    }
+
+    if (std::ranges::find(modes, present_mode) == modes.cend()) {
+        // FIFO is guaranteed to be supported by the Vulkan spec.
+        constexpr auto fallback = vk::PresentModeKHR::eFifo;
+        LOG_WARNING(Render, "Requested present mode {} is not supported, falling back to {}.",
+                    vk::to_string(present_mode), vk::to_string(fallback));
+        present_mode = fallback;
+    }
+}
+
 void Swapchain::SetSurfaceProperties() {
     const auto [capabilities_result, capabilities] =
         instance.GetPhysicalDevice().getSurfaceCapabilitiesKHR(surface);

src/video_core/renderer_vulkan/vk_swapchain.h

@@ -96,6 +96,9 @@ private:
     /// Selects the best available swapchain image format
     void FindPresentFormat();
 
+    /// Selects the best available present mode
+    void FindPresentMode();
+
     /// Sets the surface properties according to device capabilities
     void SetSurfaceProperties();
 
@@ -115,6 +118,7 @@ private:
     vk::SurfaceKHR surface{};
     vk::SurfaceFormatKHR surface_format;
     vk::Format view_format;
+    vk::PresentModeKHR present_mode;
     vk::Extent2D extent;
     vk::SurfaceTransformFlagBitsKHR transform;
     vk::CompositeAlphaFlagBitsKHR composite_alpha;