layer: Force up swapchain minImageCount

The Thing: Remastered (2958970) always creates a swapchain with 2 images in vkCreateSwapchain's minImageCount and does not respect the surface capabilities minImageCount. This causes the game to run at half framerate when SteamOS is not compositing, because we only return the image back to the game when the new one is presented on screen successfully which causes a huge stall in GPU work for the game. Forcing the image count to respect the surface capabilities at creation time fixes this problem and allows the game to run at a solid 90fps.
ValveSoftware · Dec 9, 2024 · 91f9755 · 91f9755
1 parent d317492
commit 91f9755
Showing 1 changed file with 99 additions and 68 deletions.
diff --git a/layer/VkLayer_FROG_gamescope_wsi.cpp b/layer/VkLayer_FROG_gamescope_wsi.cpp
@@ -91,6 +91,98 @@ namespace GamescopeWSILayer {
     return atoi(appid);
   }
 
+  static const char* gamescopeWaylandSocket() {
+    return std::getenv("GAMESCOPE_WAYLAND_DISPLAY");
+  }
+
+  static bool isAppInfoGamescope(const VkApplicationInfo *appInfo) {
+    if (!appInfo || !appInfo->pApplicationName)
+      return false;
+
+    return appInfo->pApplicationName == "gamescope"sv;
+  }
+
+  static bool isRunningUnderGamescope() {
+    static bool s_isRunningUnderGamescope = []() -> bool {
+      const char *gamescopeSocketName = gamescopeWaylandSocket();
+      if (!gamescopeSocketName || !*gamescopeSocketName)
+        return false;
+
+      // Gamescope always sets or unsets WAYLAND_SOCKET.
+      // So if that is set to something else, we know we cannot be running
+      // under Gamescope and must be in a nested Wayland session inside of gamescope.
+      const char *waylandSocketName = std::getenv("WAYLAND_DISPLAY");
+      if (waylandSocketName && *waylandSocketName && strcmp(gamescopeSocketName, waylandSocketName) != 0)
+        return false;
+
+      return true;
+    }();
+
+    return s_isRunningUnderGamescope;
+  }
+
+  template <typename T>
+  std::optional<T> parseEnv(const char *envName) {
+    const char *str = std::getenv(envName);
+    if (!str || !*str)
+      return std::nullopt;
+
+    T value;
+    auto result = std::from_chars(str, str + strlen(str), value);
+    if (result.ec != std::errc{})
+      return std::nullopt;
+
+    return value;
+  }
+
+  template <>
+  std::optional<bool> parseEnv(const char *envName) {
+    const char *str = std::getenv(envName);
+    if (!str || !*str)
+      return std::nullopt;
+
+    if (str == "true"sv || str == "1"sv)
+      return true;
+
+    return false;
+  }
+
+  static uint32_t getMinImageCount() {
+    static uint32_t s_minImageCount = []() -> uint32_t {
+      if (auto minCount = parseEnv<uint32_t>("GAMESCOPE_WSI_MIN_IMAGE_COUNT")) {
+        fprintf(stderr, "[Gamescope WSI] minImageCount overridden by GAMESCOPE_WSI_MIN_IMAGE_COUNT: %u\n", *minCount);
+        return *minCount;
+      }
+
+      if (auto minCount = parseEnv<uint32_t>("vk_wsi_override_min_image_count")) {
+        fprintf(stderr, "[Gamescope WSI] minImageCount overridden by vk_wsi_override_min_image_count: %u\n", *minCount);
+        return *minCount;
+      }
+
+      if (auto minCount = parseEnv<uint32_t>("vk_x11_override_min_image_count")) {
+        fprintf(stderr, "[Gamescope WSI] minImageCount overridden by vk_x11_override_min_image_count: %u\n", *minCount);
+        return *minCount;
+      }
+
+      return 3u;
+    }();
+
+    return s_minImageCount;
+  }
+
+  static bool getStrictImageCount() {
+    static bool s_strictImageCount = []() -> bool {
+      if (auto strict = parseEnv<bool>("GAMESCOPE_WSI_STRICT_IMAGE_COUNT")) {
+        return *strict;
+      }
+      if (auto strict = parseEnv<bool>("vk_x11_strict_image_count")) {
+        return *strict;
+      }
+      return false;
+    }();
+    return s_strictImageCount;
+  }
+
   // Taken from Mesa, licensed under MIT.
   //
   // No real reason to rewrite this code,
@@ -971,73 +1063,6 @@ namespace GamescopeWSILayer {
       return pDispatch->GetPhysicalDeviceWaylandPresentationSupportKHR(physicalDevice, queueFamilyIndex, gamescopeInstance->display);
     }
 
-    static const char* gamescopeWaylandSocket() {
-      return std::getenv("GAMESCOPE_WAYLAND_DISPLAY");
-    }
-
-    static bool isAppInfoGamescope(const VkApplicationInfo *appInfo) {
-      if (!appInfo || !appInfo->pApplicationName)
-        return false;
-
-      return appInfo->pApplicationName == "gamescope"sv;
-    }
-
-    static bool isRunningUnderGamescope() {
-      static bool s_isRunningUnderGamescope = []() -> bool {
-        const char *gamescopeSocketName = gamescopeWaylandSocket();
-        if (!gamescopeSocketName || !*gamescopeSocketName)
-          return false;
-
-        // Gamescope always sets or unsets WAYLAND_SOCKET.
-        // So if that is set to something else, we know we cannot be running
-        // under Gamescope and must be in a nested Wayland session inside of gamescope.
-        const char *waylandSocketName = std::getenv("WAYLAND_DISPLAY");
-        if (waylandSocketName && *waylandSocketName && strcmp(gamescopeSocketName, waylandSocketName) != 0)
-          return false;
-
-        return true;
-      }();
-
-      return s_isRunningUnderGamescope;
-    }
-
-    template <typename T>
-    static std::optional<T> parseEnv(const char *envName) {
-      const char *str = std::getenv(envName);
-      if (!str || !*str)
-        return std::nullopt;
-
-      T value;
-      auto result = std::from_chars(str, str + strlen(str), value);
-      if (result.ec != std::errc{})
-        return std::nullopt;
-
-      return value;
-    }
-
-    static uint32_t getMinImageCount() {
-      static uint32_t s_minImageCount = []() -> uint32_t {
-        if (auto minCount = parseEnv<uint32_t>("GAMESCOPE_WSI_MIN_IMAGE_COUNT")) {
-          fprintf(stderr, "[Gamescope WSI] minImageCount overridden by GAMESCOPE_WSI_MIN_IMAGE_COUNT: %u\n", *minCount);
-          return *minCount;
-        }
-
-        if (auto minCount = parseEnv<uint32_t>("vk_wsi_override_min_image_count")) {
-          fprintf(stderr, "[Gamescope WSI] minImageCount overridden by vk_wsi_override_min_image_count: %u\n", *minCount);
-          return *minCount;
-        }
-
-        if (auto minCount = parseEnv<uint32_t>("vk_x11_override_min_image_count")) {
-          fprintf(stderr, "[Gamescope WSI] minImageCount overridden by vk_x11_override_min_image_count: %u\n", *minCount);
-          return *minCount;
-        }
-
-        return 3u;
-      }();
-
-      return s_minImageCount;
-    }
-
   };
 
   class VkDeviceOverrides {
@@ -1121,9 +1146,15 @@ namespace GamescopeWSILayer {
       // We always send MAILBOX to the driver.
       swapchainInfo.presentMode = VK_PRESENT_MODE_MAILBOX_KHR;
 
-      fprintf(stderr, "[Gamescope WSI] Creating swapchain for xid: 0x%0x - minImageCount: %u - format: %s - colorspace: %s - flip: %s\n",
+      uint32_t imageCount = swapchainInfo.minImageCount;
+      if (!getStrictImageCount())
+        imageCount = std::max(getMinImageCount(), imageCount);
+      swapchainInfo.minImageCount = imageCount;
+
+      fprintf(stderr, "[Gamescope WSI] Creating swapchain for xid: 0x%0x - provided minImageCount: %u - imageCount: %u - format: %s - colorspace: %s - flip: %s\n",
         gamescopeSurface->window,
         pCreateInfo->minImageCount,
+        imageCount,
         vkroots::helpers::enumString(pCreateInfo->imageFormat),
         vkroots::helpers::enumString(pCreateInfo->imageColorSpace),
         canBypass ? "true" : "false");