ValveSoftware/Proton is a compatibility layer that enables Windows games to run on Linux via the Steam client. It integrates Wine, DXVK, vkd3d-proton, and other components to translate Windows API calls to Linux equivalents. The repository contains the build system (Makefile, Dockerfiles), the Steam client wrapper (lsteamclient) with auto-generated thunks for dozens of Steamworks SDK versions, the VR client wrapper (vrclient_x64) for OpenVR, and an OpenXR loader (wineopenxr). The codebase is heavily auto-generated from SDK headers, with manual implementations for complex interfaces. It is actively maintained by Valve and the community, with a focus on broad game compatibility. The architecture is a set of shared libraries loaded by Wine, not a standalone application.
dxwrapper is a system-level DLL proxy and compatibility layer for legacy DirectX games and applications on modern Windows (10/11). It intercepts calls to DirectDraw (1-7), Direct3D (7/8/9), DirectInput, DirectSound, and GDI, translating them to newer APIs (primarily Direct3D9) and applying numerous workarounds for rendering, input, and window management issues. The architecture is a hybrid of multiple integrated sub-projects: a core wrapper that loads real system DLLs and forwards exports while wrapping COM interfaces, plus three bundled versions of DDrawCompat (v0.2.0b, v0.2.1, v0.3.2) that hook at the user-mode display driver (D3dDdi) and GDI level. Key entry points include DllMain for each stub DLL (ddraw.dll, d3d8.dll, d3d9.dll, dsound.dll, dinput8.dll), the IClassFactory interception for COM object creation, and the configuration-driven Settings module. External dependencies include Microsoft Detours for function hooking, MemoryModule for loading DLLs from memory, and DirectXMath. The codebase is large and complex, with extensive use of COM proxy patterns, vtable hooking, and low-level Windows API patching.