Feature/opengl hook

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 +113,10 @@ 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)
+    elseif (UNIX AND NOT APPLE)
+        find_package(OpenGL REQUIRED)
+        target_link_libraries(${PROJECT_NAME} PRIVATE OpenGL::GL ${CMAKE_DL_LIBS})
     endif ()
 endif ()
 

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()
 

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)

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;
+}

include/omath/hooks/hooks_manager.hpp

@@ -3,9 +3,11 @@
 #ifdef OMATH_ENABLE_HOOKING
 #include <cstdint>
 #include <functional>
+#include <memory>
 #include <optional>
 #include <shared_mutex>
 
+#ifdef _WIN32
 #ifndef WIN32_LEAN_AND_MEAN
 #define WIN32_LEAN_AND_MEAN
 #endif
@@ -16,6 +18,12 @@
 #include <d3d12.h>
 #include <d3d9.h>
 #include <dxgi.h>
+#endif // _WIN32
+
+#ifdef __linux__
+#include <GL/glx.h>
+#endif // __linux__
+
 #include <safetyhook.hpp>
 
 namespace omath::hooks
@@ -25,6 +33,7 @@ namespace omath::hooks
         HooksManager() = default;
 
     public:
+#ifdef _WIN32
         // IDXGISwapChain callbacks — shared between DX11 and DX12 (same interface, same signature).
         using present_callback = std::function<void(IDXGISwapChain*, UINT, UINT)>;
         using resize_buffers_callback = std::function<void(IDXGISwapChain*, UINT, UINT, UINT, DXGI_FORMAT, UINT)>;
@@ -37,14 +46,27 @@ namespace omath::hooks
         using dx9_reset_callback = std::function<void(IDirect3DDevice9*, D3DPRESENT_PARAMETERS*)>;
         using dx9_end_scene_callback = std::function<void(IDirect3DDevice9*)>;
 
+        // OpenGL callback — Windows. 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)>;
+#endif // _WIN32
+
+#ifdef __linux__
+        // OpenGL/GLX callback — Linux. Fires before glXSwapBuffers calls the original.
+        using opengl_swap_buffers_callback = std::function<void(Display*, GLXDrawable)>;
+#endif // __linux__
+
+        template<typename Callback>
+        using callback_ptr = std::shared_ptr<const Callback>;
 
         [[nodiscard]] static HooksManager& get();
         HooksManager(const HooksManager&) = delete;
         HooksManager& operator=(const HooksManager&) = delete;
         ~HooksManager();
 
+#ifdef _WIN32
         [[nodiscard]] bool hook_dx9();
         void unhook_dx9();
         void set_on_dx9_present(dx9_present_callback callback);
@@ -56,7 +78,13 @@ namespace omath::hooks
 
         [[nodiscard]] bool hook_dx12();
         void unhook_dx12();
+#endif // _WIN32
+
+        [[nodiscard]] bool hook_opengl();
+        void unhook_opengl();
+        void set_on_opengl_swap_buffers(opengl_swap_buffers_callback callback);
 
+#ifdef _WIN32
         // 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);
@@ -65,8 +93,10 @@ namespace omath::hooks
         [[nodiscard]] bool hook_wnd_proc(HWND hwnd);
         void unhook_wnd_proc();
         void set_on_wnd_proc(wnd_proc_callback callback);
+#endif // _WIN32
 
     private:
+#ifdef _WIN32
         [[nodiscard]]
         static HRESULT __stdcall dx9_present_detour(IDirect3DDevice9* p_device, const RECT* p_source_rect,
                                                     const RECT* p_dest_rect, HWND h_dest_window_override,
@@ -91,11 +121,22 @@ 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);
+#endif // _WIN32
+
+#ifdef __linux__
+        static void opengl_glx_swap_buffers_detour(Display* display, GLXDrawable drawable);
+#endif // __linux__
 
         mutable std::shared_mutex m_hook_state_mutex;
 
+#ifdef _WIN32
         mutable std::shared_mutex m_dx9_present_mutex;
         mutable std::shared_mutex m_dx9_reset_mutex;
         mutable std::shared_mutex m_dx9_end_scene_mutex;
@@ -105,7 +146,11 @@ namespace omath::hooks
         mutable std::shared_mutex m_execute_command_lists_mutex;
 
         mutable std::shared_mutex m_wnd_proc_mutex;
+#endif // _WIN32
 
+        mutable std::shared_mutex m_opengl_swap_buffers_mutex;
+
+#ifdef _WIN32
         bool m_is_dx9_hooked = false;
         bool m_is_dx11_hooked = false;
         bool m_is_dx12_hooked = false;
@@ -125,14 +170,29 @@ namespace omath::hooks
         safetyhook::InlineHook m_dx12_resize_buffers_hook;
         safetyhook::InlineHook m_dx12_execute_command_lists_hook;
 
-        dx9_present_callback m_dx9_present_cb;
-        dx9_reset_callback m_dx9_reset_cb;
-        dx9_end_scene_callback m_dx9_end_scene_cb;
+        safetyhook::InlineHook m_opengl_wgl_swap_buffers_hook;
+        safetyhook::InlineHook m_opengl_swap_buffers_hook;
+#endif // _WIN32
+
+#ifdef __linux__
+        safetyhook::InlineHook m_opengl_glx_swap_buffers_hook;
+#endif // __linux__
+
+        bool m_is_opengl_hooked = false;
+
+#ifdef _WIN32
+        callback_ptr<dx9_present_callback> m_dx9_present_cb;
+        callback_ptr<dx9_reset_callback> m_dx9_reset_cb;
+        callback_ptr<dx9_end_scene_callback> m_dx9_end_scene_cb;
+
+        callback_ptr<present_callback> m_present_cb;
+        callback_ptr<resize_buffers_callback> m_resize_buffers_cb;
+        callback_ptr<execute_command_lists_callback> m_execute_command_lists_cb;
+
+        callback_ptr<wnd_proc_callback> m_wnd_proc_cb;
+#endif // _WIN32
 
-        present_callback m_present_cb;
-        resize_buffers_callback m_resize_buffers_cb;
-        execute_command_lists_callback m_execute_command_lists_cb;
-        wnd_proc_callback m_wnd_proc_cb;
+        callback_ptr<opengl_swap_buffers_callback> m_opengl_swap_buffers_cb;
     };
 } // namespace omath::hooks