From d90164cab827a7085fe02e37dae05d2e2d57f810 Mon Sep 17 00:00:00 2001
From: Orange <orange-cpp@yandex.ru>
Date: Wed, 6 May 2026 20:05:45 +0300
Subject: [PATCH] added opengl hook

---
 .idea/editor.xml                            |   1 +
 .idea/omath.iml                             |   2 -
 CMakeLists.txt                              |   4 +-
 examples/CMakeLists.txt                     |   7 +-
 examples/example_opengl_hook/CMakeLists.txt |  13 +++
 examples/example_opengl_hook/dllmain.cpp    | 116 ++++++++++++++++++++
 include/omath/hooks/hooks_manager.hpp       |  18 +++
 source/hooks/hooks_manager.cpp              | 103 +++++++++++++++++
 8 files changed, 257 insertions(+), 7 deletions(-)
 delete mode 100644 .idea/omath.iml
 create mode 100644 examples/example_opengl_hook/CMakeLists.txt
 create mode 100644 examples/example_opengl_hook/dllmain.cpp

diff --git a/.idea/editor.xml b/.idea/editor.xml
index 9b5acf8..45d6cbc 100644
--- a/.idea/editor.xml
+++ b/.idea/editor.xml
@@ -139,6 +139,7 @@
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppNotAllPathsReturnValue/@EntryIndexedValue" value="WARNING" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppObjectMemberMightNotBeInitialized/@EntryIndexedValue" value="WARNING" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppOutParameterMustBeWritten/@EntryIndexedValue" value="WARNING" type="string" />
+    <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppOverrideWithDifferentVisibility/@EntryIndexedValue" value="WARNING" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppParameterMayBeConst/@EntryIndexedValue" value="HINT" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppParameterMayBeConstPtrOrRef/@EntryIndexedValue" value="SUGGESTION" type="string" />
     <option name="/Default/CodeInspection/Highlighting/InspectionSeverities/=CppParameterNamesMismatch/@EntryIndexedValue" value="HINT" type="string" />
diff --git a/.idea/omath.iml b/.idea/omath.iml
deleted file mode 100644
index 4c94235..0000000
--- a/.idea/omath.iml
+++ /dev/null
@@ -1,2 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<module classpath="CIDR" type="CPP_MODULE" version="4" />
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 35be5e7..9d9eae0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -32,7 +32,7 @@ option(OMATH_ENABLE_FORCE_INLINE
        "Will for compiler to make some functions to be force inlined no matter what" ON)
 option(OMATH_ENABLE_LUA
         "omath bindings for lua" OFF)
-option(OMATH_ENABLE_HOOKING "omath will HooksManager that can hook DirectX automatically" OFF)
+option(OMATH_ENABLE_HOOKING "omath will HooksManager that can hook DirectX/OpenGL automatically" OFF)
 
 if(VCPKG_MANIFEST_FEATURES)
     foreach(omath_feature IN LISTS VCPKG_MANIFEST_FEATURES)
@@ -113,7 +113,7 @@ if (OMATH_ENABLE_HOOKING)
     target_link_libraries(${PROJECT_NAME} PRIVATE safetyhook::safetyhook)
 
     if (WIN32)
-        target_link_libraries(${PROJECT_NAME} PRIVATE d3d9 d3d11 d3d12 dxgi)
+        target_link_libraries(${PROJECT_NAME} PRIVATE d3d9 d3d11 d3d12 dxgi opengl32 gdi32)
     endif ()
 endif ()
 
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 200ab71..3d65eae 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -5,15 +5,16 @@ add_subdirectory(example_signature_scan)
 add_subdirectory(example_hud)
 
 if(OMATH_ENABLE_HOOKING AND WIN32)
-    # Requires imgui with dx9-binding, dx11-binding, dx12-binding, win32-binding.
-    # Install via: vcpkg install imgui[dx9-binding,dx11-binding,dx12-binding,win32-binding]
+    # Requires imgui with dx9-binding, dx11-binding, dx12-binding, opengl3-binding, win32-binding.
+    # Install via: vcpkg install imgui[dx9-binding,dx11-binding,dx12-binding,opengl3-binding,win32-binding]
     find_package(imgui CONFIG QUIET)
     if(imgui_FOUND)
         add_subdirectory(example_dx9_hook)
         add_subdirectory(example_dx11_hook)
         add_subdirectory(example_dx12_hook)
+        add_subdirectory(example_opengl_hook)
     else()
-        message(STATUS "[omath] imgui not found — DX hook examples skipped")
+        message(STATUS "[omath] imgui not found - hook examples skipped")
     endif()
 endif()
 
diff --git a/examples/example_opengl_hook/CMakeLists.txt b/examples/example_opengl_hook/CMakeLists.txt
new file mode 100644
index 0000000..5291266
--- /dev/null
+++ b/examples/example_opengl_hook/CMakeLists.txt
@@ -0,0 +1,13 @@
+project(example_opengl_hook)
+
+add_library(${PROJECT_NAME} MODULE dllmain.cpp)
+
+set_target_properties(${PROJECT_NAME} PROPERTIES
+    CXX_STANDARD 23
+    MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>"
+    ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/out/${CMAKE_BUILD_TYPE}"
+    LIBRARY_OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/out/${CMAKE_BUILD_TYPE}"
+    RUNTIME_OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/out/${CMAKE_BUILD_TYPE}")
+
+find_package(imgui CONFIG REQUIRED)
+target_link_libraries(${PROJECT_NAME} PRIVATE omath::omath imgui::imgui opengl32 gdi32)
diff --git a/examples/example_opengl_hook/dllmain.cpp b/examples/example_opengl_hook/dllmain.cpp
new file mode 100644
index 0000000..1157a3e
--- /dev/null
+++ b/examples/example_opengl_hook/dllmain.cpp
@@ -0,0 +1,116 @@
+#include "omath/hooks/hooks_manager.hpp"
+#include <Windows.h>
+#include <chrono>
+#include <imgui.h>
+#include <imgui_impl_opengl3.h>
+#include <imgui_impl_win32.h>
+#include <optional>
+#include <thread>
+
+extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND, UINT, WPARAM, LPARAM);
+
+namespace
+{
+    bool g_initialized = false;
+    bool g_init_attempted = false;
+    bool g_show_menu = true;
+
+    constexpr auto g_module_wait_delay = std::chrono::milliseconds{100};
+
+    void init(HDC hdc)
+    {
+        g_init_attempted = true;
+
+        const HWND hwnd = WindowFromDC(hdc);
+        if (!hwnd)
+            return;
+
+        ImGui::CreateContext();
+        ImGui::StyleColorsDark();
+        ImGui::GetIO().IniFilename = nullptr;
+        ImGui::GetIO().LogFilename = nullptr;
+        ImGui::GetIO().ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange;
+
+        ImGui_ImplWin32_Init(hwnd);
+        ImGui_ImplOpenGL3_Init();
+
+        auto& mgr = omath::hooks::HooksManager::get();
+        mgr.set_on_wnd_proc(
+                [](HWND h, UINT msg, WPARAM wp, LPARAM lp) -> std::optional<LRESULT>
+                {
+                    if (!g_show_menu)
+                        return std::nullopt;
+
+                    if (ImGui_ImplWin32_WndProcHandler(h, msg, wp, lp))
+                        return 0;
+                    return std::nullopt;
+                });
+        (void)mgr.hook_wnd_proc(hwnd);
+
+        g_initialized = true;
+    }
+
+    void on_swap_buffers(HDC hdc)
+    {
+        if (!g_initialized)
+        {
+            if (!g_init_attempted)
+                init(hdc);
+            return;
+        }
+
+        if (GetAsyncKeyState(VK_INSERT) & 1)
+            g_show_menu = !g_show_menu;
+
+        ImGui_ImplOpenGL3_NewFrame();
+        ImGui_ImplWin32_NewFrame();
+        ImGui::NewFrame();
+
+        if (g_show_menu)
+        {
+            ImGui::SetNextWindowSize({300.f, 100.f}, ImGuiCond_Once);
+            ImGui::SetNextWindowPos({10.f, 10.f}, ImGuiCond_Once);
+            ImGui::Begin("omath | OpenGL hook");
+            ImGui::Text("Hook active");
+            ImGui::Text("FPS: %.1f", ImGui::GetIO().Framerate);
+            ImGui::Text("INSERT toggles this window");
+            ImGui::End();
+        }
+
+        ImGui::Render();
+        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+    }
+
+    void hook_when_opengl_is_loaded()
+    {
+        while (!GetModuleHandle("opengl32.dll"))
+            std::this_thread::sleep_for(g_module_wait_delay);
+
+        auto& mgr = omath::hooks::HooksManager::get();
+        mgr.set_on_opengl_swap_buffers(on_swap_buffers);
+        (void)mgr.hook_opengl();
+    }
+} // namespace
+
+BOOL WINAPI DllMain(HINSTANCE h_instance, DWORD reason, LPVOID)
+{
+    if (reason == DLL_PROCESS_ATTACH)
+    {
+        DisableThreadLibraryCalls(h_instance);
+        std::thread{hook_when_opengl_is_loaded}.detach();
+    }
+    else if (reason == DLL_PROCESS_DETACH)
+    {
+        auto& mgr = omath::hooks::HooksManager::get();
+        mgr.unhook_wnd_proc();
+        mgr.unhook_opengl();
+
+        if (g_initialized)
+        {
+            ImGui_ImplOpenGL3_Shutdown();
+            ImGui_ImplWin32_Shutdown();
+            ImGui::DestroyContext();
+        }
+    }
+    return true;
+}
diff --git a/include/omath/hooks/hooks_manager.hpp b/include/omath/hooks/hooks_manager.hpp
index e902357..8833746 100644
--- a/include/omath/hooks/hooks_manager.hpp
+++ b/include/omath/hooks/hooks_manager.hpp
@@ -37,6 +37,9 @@ namespace omath::hooks
         using dx9_reset_callback = std::function<void(IDirect3DDevice9*, D3DPRESENT_PARAMETERS*)>;
         using dx9_end_scene_callback = std::function<void(IDirect3DDevice9*)>;
 
+        // OpenGL callbacks. Fires before the hooked buffer swap function calls the original.
+        using opengl_swap_buffers_callback = std::function<void(HDC)>;
+
         // Return nullopt to pass the message to the original WndProc; return a value to intercept it.
         using wnd_proc_callback = std::function<std::optional<LRESULT>(HWND, UINT, WPARAM, LPARAM)>;
 
@@ -57,6 +60,10 @@ namespace omath::hooks
         [[nodiscard]] bool hook_dx12();
         void unhook_dx12();
 
+        [[nodiscard]] bool hook_opengl();
+        void unhook_opengl();
+        void set_on_opengl_swap_buffers(opengl_swap_buffers_callback callback);
+
         // Present and ResizeBuffers callbacks fire for whichever of DX11/DX12 is hooked.
         void set_on_present(present_callback callback);
         void set_on_resize_buffers(resize_buffers_callback callback);
@@ -91,6 +98,11 @@ namespace omath::hooks
                                                                 UINT num_command_lists,
                                                                 ID3D12CommandList* const* pp_command_lists);
 
+        [[nodiscard]]
+        static BOOL __stdcall opengl_wgl_swap_buffers_detour(HDC hdc);
+        [[nodiscard]]
+        static BOOL __stdcall opengl_swap_buffers_detour(HDC hdc);
+
         [[nodiscard]]
         static LRESULT __stdcall wnd_proc_detour(HWND hwnd, UINT msg, WPARAM w_param, LPARAM l_param);
 
@@ -104,11 +116,13 @@ namespace omath::hooks
         mutable std::shared_mutex m_resize_buffers_mutex;
         mutable std::shared_mutex m_execute_command_lists_mutex;
 
+        mutable std::shared_mutex m_opengl_swap_buffers_mutex;
         mutable std::shared_mutex m_wnd_proc_mutex;
 
         bool m_is_dx9_hooked = false;
         bool m_is_dx11_hooked = false;
         bool m_is_dx12_hooked = false;
+        bool m_is_opengl_hooked = false;
         bool m_is_wnd_proc_hooked = false;
 
         HWND m_hooked_hwnd = nullptr;
@@ -125,6 +139,9 @@ namespace omath::hooks
         safetyhook::InlineHook m_dx12_resize_buffers_hook;
         safetyhook::InlineHook m_dx12_execute_command_lists_hook;
 
+        safetyhook::InlineHook m_opengl_wgl_swap_buffers_hook;
+        safetyhook::InlineHook m_opengl_swap_buffers_hook;
+
         dx9_present_callback m_dx9_present_cb;
         dx9_reset_callback m_dx9_reset_cb;
         dx9_end_scene_callback m_dx9_end_scene_cb;
@@ -132,6 +149,7 @@ namespace omath::hooks
         present_callback m_present_cb;
         resize_buffers_callback m_resize_buffers_cb;
         execute_command_lists_callback m_execute_command_lists_cb;
+        opengl_swap_buffers_callback m_opengl_swap_buffers_cb;
         wnd_proc_callback m_wnd_proc_cb;
     };
 } // namespace omath::hooks
diff --git a/source/hooks/hooks_manager.cpp b/source/hooks/hooks_manager.cpp
index 316edc2..b40ae43 100644
--- a/source/hooks/hooks_manager.cpp
+++ b/source/hooks/hooks_manager.cpp
@@ -5,6 +5,8 @@
 
 namespace
 {
+    thread_local bool g_is_inside_opengl_swap_buffers = false;
+
     class DummyWindow final
     {
         WNDCLASSEX m_window_class{};
@@ -43,6 +45,15 @@ namespace
         return (*reinterpret_cast<void***>(com_obj))[index];
     }
 
+    void* module_proc(const char* module_name, const char* proc_name)
+    {
+        const HMODULE module = GetModuleHandle(module_name);
+        if (!module)
+            return nullptr;
+
+        return reinterpret_cast<void*>(GetProcAddress(module, proc_name));
+    }
+
     struct dx12_vtable_fns
     {
         void* present;
@@ -169,6 +180,7 @@ namespace omath::hooks
         unhook_dx9();
         unhook_dx11();
         unhook_dx12();
+        unhook_opengl();
     }
 
     bool HooksManager::hook_dx9()
@@ -381,6 +393,49 @@ namespace omath::hooks
         m_is_dx12_hooked = false;
     }
 
+    bool HooksManager::hook_opengl()
+    {
+        std::unique_lock lock(m_hook_state_mutex);
+        if (m_is_opengl_hooked)
+            return true;
+
+        if (void* wgl_swap_buffers = module_proc("opengl32.dll", "wglSwapBuffers"))
+        {
+            m_opengl_wgl_swap_buffers_hook = safetyhook::create_inline(
+                    wgl_swap_buffers, reinterpret_cast<void*>(&opengl_wgl_swap_buffers_detour));
+        }
+
+        if (void* swap_buffers = module_proc("gdi32.dll", "SwapBuffers"))
+        {
+            m_opengl_swap_buffers_hook =
+                    safetyhook::create_inline(swap_buffers, reinterpret_cast<void*>(&opengl_swap_buffers_detour));
+        }
+
+        if (!m_opengl_wgl_swap_buffers_hook && !m_opengl_swap_buffers_hook)
+        {
+            m_opengl_wgl_swap_buffers_hook = {};
+            m_opengl_swap_buffers_hook = {};
+            return false;
+        }
+
+        m_is_opengl_hooked = true;
+        return true;
+    }
+
+    void HooksManager::unhook_opengl()
+    {
+        std::unique_lock lock(m_hook_state_mutex);
+        m_opengl_wgl_swap_buffers_hook = {};
+        m_opengl_swap_buffers_hook = {};
+        m_is_opengl_hooked = false;
+    }
+
+    void HooksManager::set_on_opengl_swap_buffers(opengl_swap_buffers_callback callback)
+    {
+        std::unique_lock lock(m_opengl_swap_buffers_mutex);
+        m_opengl_swap_buffers_cb = std::move(callback);
+    }
+
     void HooksManager::set_on_present(present_callback callback)
     {
         std::unique_lock lock(m_present_mutex);
@@ -553,6 +608,54 @@ namespace omath::hooks
         mgr.m_dx12_execute_command_lists_hook.call<void>(p_command_queue, num_command_lists, pp_command_lists);
     }
 
+    BOOL __stdcall HooksManager::opengl_wgl_swap_buffers_detour(HDC hdc)
+    {
+        auto& mgr = get();
+
+        if (!g_is_inside_opengl_swap_buffers)
+        {
+            g_is_inside_opengl_swap_buffers = true;
+
+            opengl_swap_buffers_callback cb;
+            {
+                std::shared_lock lock(mgr.m_opengl_swap_buffers_mutex);
+                cb = mgr.m_opengl_swap_buffers_cb;
+            }
+            if (cb)
+                cb(hdc);
+
+            const BOOL result = mgr.m_opengl_wgl_swap_buffers_hook.call<BOOL>(hdc);
+            g_is_inside_opengl_swap_buffers = false;
+            return result;
+        }
+
+        return mgr.m_opengl_wgl_swap_buffers_hook.call<BOOL>(hdc);
+    }
+
+    BOOL __stdcall HooksManager::opengl_swap_buffers_detour(HDC hdc)
+    {
+        auto& mgr = get();
+
+        if (!g_is_inside_opengl_swap_buffers)
+        {
+            g_is_inside_opengl_swap_buffers = true;
+
+            opengl_swap_buffers_callback cb;
+            {
+                std::shared_lock lock(mgr.m_opengl_swap_buffers_mutex);
+                cb = mgr.m_opengl_swap_buffers_cb;
+            }
+            if (cb)
+                cb(hdc);
+
+            const BOOL result = mgr.m_opengl_swap_buffers_hook.call<BOOL>(hdc);
+            g_is_inside_opengl_swap_buffers = false;
+            return result;
+        }
+
+        return mgr.m_opengl_swap_buffers_hook.call<BOOL>(hdc);
+    }
+
     LRESULT __stdcall HooksManager::wnd_proc_detour(HWND hwnd, UINT msg, WPARAM w_param, LPARAM l_param)
     {
         auto& mgr = get();