<img src="assets/HydraHook_128x128.png" align="left" /> HydraHook

API-Hooking and rendering framework for DirectX-based games.

About

HydraHook consists of a self-contained library (DLL) which exposes a minimalistic API for rendering custom content in foreign processes eliminating the need for in-depth knowledge about Direct3D and API-hooking. The most common use-case might be drawing custom overlays on top of your games. The framework takes care about pesky tasks like detecting the DirectX version the game was built for.

[!CAUTION]
Use caution when injecting HydraHook into any game protected by anti-cheat software. API hooking and DLL injection are commonly detected by anti-cheat systems and may result in permanent bans from online services. Use only with games you own and in environments where such use is permitted.

[!NOTE]
The authors of this project do not condone the use of HydraHook in cheating software. The project's motivation has been curiosity and education entirely.

Features

Runtime injection and ejection — No launcher required. Inject into any running DirectX process and eject via FreeLibrary when done. Supports mid-process injection (e.g. D3D12 games already running). Graceful shutdown via ExitProcess / PostQuitMessage / FreeLibrary hooks avoids loader-lock and unload races.
Performance-focused — Lock-free hot path for hook callbacks (atomic counters only; no mutex, no kernel transition). Shutdown uses loader-lock-safe remove_nothrow to avoid deadlocks during process exit.
No external dependencies at runtime — Everything needed is statically linked in. Just drop the DLL into the target process; no redistributables or runtime packages required.

Supported DirectX versions

DirectX 9.0
DirectX 9.0 Extended (Vista+)
DirectX 10
DirectX 11
DirectX 12

How to build

Prerequisites

Visual Studio 2022 (Community Edition is free)
Windows SDK

Build steps

Clone the repository and initialize submodules: git submodule update --init --recursive
Open HydraHook.sln in Visual Studio and build

Dependencies (spdlog, detours, imgui, directxtk) are declared in vcpkg.json and installed via vcpkg (included as a submodule). Run prepare-deps.bat from a Developer Command Prompt for VS 2022 (or x64 Native Tools Command Prompt) before the first build in Visual Studio; the build will use existing vcpkg_installed if present.

Pre-built binaries

[!WARNING]
The downloads contain a DLL Injector utility which might be flagged as unsafe by the browser due to it sharing behavior with malicious code. Use at your own risk!

Last updated

Pre-built binaries are available from the buildbot. Note: these builds may be outdated; for the latest code, build from source.

How to use

Inject the resulting host library (e.g. HydraHook-ImGui.dll) into the target process first using a DLL injection utility of your choice (you can ofc. use mine as well). The following example loads the imgui sample:

PowerShell
.\Injector -n hl2.exe -i HydraHook-ImGui.dll

Just make sure your host library doesn't require any external dependencies not present in the process context or you'll get a LoadLibrary failed error.

Diagnostics

The core library logs its progress and potential errors to HydraHook.log. It tries to write in this order: (1) the directory of the process executable, (2) the directory of the HydraHook DLL, (3) %TEMP% if both prior locations fail (e.g. no write permissions).