From 44dcc2b7d0fe9027c064c50ebd5fecd8a2a409ee Mon Sep 17 00:00:00 2001
From: PancakeTAS <pancake@mgnet.work>
Date: Thu, 25 Dec 2025 05:55:54 +0100
Subject: [PATCH] feat: mangohud integration

---
 CMakeLists.txt                  |  4 ++++
 lsfg-vk-layer/src/swapchain.cpp | 34 +++++++++++++++++++++++++++++++++
 lsfg-vk-layer/src/swapchain.hpp |  8 ++++++++
 3 files changed, 46 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c0b7f95..7b5a6b6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,7 @@ option(LSFGVK_BUILD_CLI          "Build the command line interface"  ON)
 option(LSFGVK_INSTALL_DEVELOP    "Install development libraries and headers"      OFF)
 option(LSFGVK_INSTALL_XDG_FILES  "Install the application icon and desktop files" OFF)
 set(LSFGVK_LAYER_LIBRARY_PATH liblsfg-vk-layer.so CACHE STRING "Change where Vulkan searches for the layer library")
+option(LSFGVK_LAYER_MANGOHUD     "Enable MangoHud support in the Vulkan layer"        ON)
 option(LSFGVK_TESTING_RENDERDOC  "Enable RenderDoc integration for testing purposes" OFF)
 # === READ HERE FOR BUILD OPTIONS ===
 
@@ -44,6 +45,9 @@ if(CMAKE_BUILD_TYPE STREQUAL "Debug")
     endif()
 endif()
 
+if(LSFGVK_LAYER_MANGOHUD)
+    add_compile_definitions(LSFGVK_LAYER_MANGOHUD)
+endif()
 if(LSFGVK_TESTING_RENDERDOC)
     add_compile_definitions(LSFGVK_TESTING_RENDERDOC)
 endif()
diff --git a/lsfg-vk-layer/src/swapchain.cpp b/lsfg-vk-layer/src/swapchain.cpp
index 1c50226..f5bf754 100644
--- a/lsfg-vk-layer/src/swapchain.cpp
+++ b/lsfg-vk-layer/src/swapchain.cpp
@@ -21,10 +21,15 @@
 
 #include <vulkan/vulkan_core.h>
 
+#ifdef LSFGVK_LAYER_MANGOHUD
+#include <dlfcn.h>
+#endif
+
 using namespace lsfgvk;
 using namespace lsfgvk::layer;
 
 namespace {
+    /// helper to create an image memory barrier
     VkImageMemoryBarrier barrierHelper(VkImage handle,
             VkAccessFlags srcAccessMask,
             VkAccessFlags dstAccessMask,
@@ -48,6 +53,21 @@ namespace {
             }
         };
     }
+#ifdef LSFGVK_LAYER_MANGOHUD
+    /// load MangoHud integration
+    PFN_MangoHud_notify loadMangoHudIntegration() {
+        void* module = dlopen("libMangoHud.so", RTLD_NOW | RTLD_NOLOAD);
+        if (!module)
+            return nullptr;
+
+        auto func = reinterpret_cast<PFN_MangoHud_notify>(
+            dlsym(module, "notify_extra_frame"));
+        if (!func)
+            return nullptr;
+
+        return func;
+    }
+#endif
 }
 
 void layer::context_ModifySwapchainCreateInfo(const ls::GameConf& profile, uint32_t maxImages,
@@ -124,6 +144,10 @@ Swapchain::Swapchain(const vk::Vulkan& vk, backend::Instance& backend,
             vk::Semaphore(vk)
         );
     }
+
+#ifdef LSFGVK_LAYER_MANGOHUD
+    this->mangohud_notify = loadMangoHudIntegration();
+#endif
 }
 
 VkResult Swapchain::present(const vk::Vulkan& vk,
@@ -281,6 +305,11 @@ VkResult Swapchain::present(const vk::Vulkan& vk,
         if (res != VK_SUCCESS && res != VK_SUBOPTIMAL_KHR)
             throw ls::vulkan_error(res, "vkQueuePresentKHR() failed");
 
+#ifdef LSFGVK_LAYER_MANGOHUD
+        if (this->mangohud_notify)
+            this->mangohud_notify(this->fidx, swapchain, true);
+#endif
+
         this->idx++;
     }
 
@@ -298,6 +327,11 @@ VkResult Swapchain::present(const vk::Vulkan& vk,
     if (res != VK_SUCCESS && res != VK_SUBOPTIMAL_KHR)
         throw ls::vulkan_error(res, "vkQueuePresentKHR() failed");
 
+#ifdef LSFGVK_LAYER_MANGOHUD
+    if (this->mangohud_notify)
+        this->mangohud_notify(this->fidx, swapchain, false);
+#endif
+
     this->fidx++;
     return res;
 }
diff --git a/lsfg-vk-layer/src/swapchain.hpp b/lsfg-vk-layer/src/swapchain.hpp
index 3c711a0..b510119 100644
--- a/lsfg-vk-layer/src/swapchain.hpp
+++ b/lsfg-vk-layer/src/swapchain.hpp
@@ -36,6 +36,10 @@ namespace lsfgvk::layer {
     void context_ModifySwapchainCreateInfo(const ls::GameConf& profile, uint32_t maxImages,
         VkSwapchainCreateInfoKHR& createInfo);
 
+#ifdef LSFGVK_LAYER_MANGOHUD
+    using PFN_MangoHud_notify = void(*)(uint64_t, VkSwapchainKHR, bool);
+#endif
+
     /// swapchain context for a layer instance
     class Swapchain {
     public:
@@ -79,6 +83,10 @@ namespace lsfgvk::layer {
 
         ls::GameConf profile;
         SwapchainInfo info;
+
+#ifdef LSFGVK_LAYER_MANGOHUD
+        PFN_MangoHud_notify mangohud_notify{nullptr};
+#endif
     };
 
 }