RenderHook

Minimal render-hooking framework for Windows that injects a small ImGui overlay into apps using DirectX 9/11/12 or OpenGL. Built with MinHook. Educational use.

What it does

• Installs function hooks on the app’s render path.
• Boots ImGui (Win32 + backend) and draws per-frame UI.
• Unhooks cleanly and restores original state.

Not for protected/anti‑cheat environments.

Backends

• DX9 – Present, Reset
• DX11 – IDXGISwapChain::Present, ResizeBuffers (vtable via dummy device)
• DX12 – swap chain present path, RTV heap, per‑frame contexts
• OpenGL – wglSwapBuffers

Quick start

Requirements

• Windows 10/11, Visual Studio 2022 (C++17+), Windows SDK
• Deps: MinHook, Dear ImGui (imgui_impl_win32, imgui_impl_dx9/dx11/dx12, imgui_impl_opengl3)

Build

1. Open the project in VS.
2. Select x86/x64 to match the target process.
3. Build the DLL in Release.

Inject

• Inject the DLL into a process using the desired API.
• Choose a backend in dllmain.cpp:

RenderHook::SetRenderingBackend(DIRECTX11);

Controls

• HOME – toggle overlay
• END – unhook + unload

How it’s wired (short)

1. DllMain spawns a worker thread + console logs.
2. RenderHook::SetRenderingBackend(...) installs API‑specific hooks.
3. Vtable/function resolution per backend.
4. ImGui init: Win32 + renderer backend.
5. Hooked Present/SwapBuffers → new frame → draw → call original.

Files

/dllmain.cpp
/renderhook.h|.cpp
/dx9hook.cpp
/dx11hook.cpp
/dx12hook.cpp
/openglhook.cpp

API

enum RenderBackend { DIRECTX9, DIRECTX11, DIRECTX12, OPENGL };

namespace RenderHook {
  void SetRenderingBackend(RenderBackend backend);
  void Unhook();
}

Roadmap

• Automatic API detection.
• Shared helpers across backends.
• Vulkan backend.

Images

Credits

• TsudaKageyu/minhook – function hooking
• ocornut/imgui – UI

License

Pick a permissive license (MIT/BSD/Apache‑2.0).