feat(build): Add native Linux build support

[sebyx07]

Summary

Add native Linux compilation support alongside existing Windows builds. Currently, the Docker-based build produces Windows executables (.exe) that run via Wine — this proposal adds true native Linux binaries.

Problem

Current State

• Docker build (scripts/docker-build.sh) exists but produces Windows .exe files
• Linux users must run the game through Wine/Proton
• No way to compile native Linux binaries directly
• Scripts don't clearly indicate they produce Windows executables, not native Linux

Why Native Linux?

• Better performance (no Wine overhead)
• Easier debugging with native tools (gdb, valgrind)
• Simpler CI/CD without Docker containers
• First-class Linux support for the community

Solution

Core Approach: DXVK

Use DXVK to translate DirectX 8 calls to Vulkan at runtime. This allows the existing DirectX rendering code to work on Linux with minimal source code changes.

DirectX 8 Code (unchanged) → DXVK Library → Vulkan → GPU

Key Changes

1. CMake Feature Toggles

   option(RTS_USE_DXVK "Use DXVK (DirectX->Vulkan)" OFF)
   option(RTS_USE_FFMPEG "Use FFmpeg for video" ON)
   option(RTS_USE_OPENAL "Use OpenAL for audio" OFF)
   
   cmake_dependent_option(RTS_USE_DX8 "Use DirectX 8" ON "WIN32" OFF)
   cmake_dependent_option(RTS_USE_DXVK "Use DXVK" ON "NOT WIN32" OFF)

2. Linux CMake Presets

   {
     "name": "linux",
     "displayName": "Linux x64 Release",
     "generator": "Ninja",
     "binaryDir": "${sourceDir}/build/linux",
     "cacheVariables": {
       "CMAKE_BUILD_TYPE": "Release",
       "RTS_USE_DXVK": "ON",
       "RTS_USE_FFMPEG": "ON"
     }
   }

3. Platform Detection

   if(WIN32)
     target_compile_definitions(core_config INTERFACE _WINDOWS)
   elseif(UNIX AND NOT APPLE)
     target_compile_definitions(core_config INTERFACE _LINUX _UNIX)
   endif()

Dependency Matrix

Component	Windows	Linux (Native)
Graphics	DirectX 8	DXVK (DX8→Vulkan)
Video	Bink	FFmpeg
Audio	Miles	Miles*/OpenAL
Fonts	GDI	FreeType + FontConfig
File I/O	Win32 API	std::filesystem (StdDevice)
Windowing	Win32	SDL3 or X11
Input	DirectInput	SDL3 or libevdev

*Miles may work via compatibility layer

Existing Infrastructure

The codebase already has cross-platform foundations:

• StdLocalFileSystem - Uses std::filesystem, handles path separators and case-insensitivity
• Compatibility headers in Dependencies/Utility/Utility/:
  • compat.h, thread_compat.h, endian_compat.h, intrin_compat.h
• FFmpeg video backend - Already exists in Core/GameEngineDevice/Source/VideoDevice/FFmpeg/

Reference Implementation

Fighter19's fork (develop branch) demonstrates a working approach with:

• DXVK integration
• SDL3 support
• CMake feature toggles
• Linux CI builds

Tasks

Phase 1: CMake Restructuring

• Add feature toggle options (RTS_USE_DXVK, RTS_USE_FFMPEG, RTS_USE_OPENAL, etc.)
• Add platform detection defines (_LINUX, _UNIX)
• Add linux and linux-debug presets to CMakePresets.json
• Create cmake/platform-deps.cmake for centralized dependency handling
• Create cmake/game-install.cmake helper to reduce CMake duplication

Phase 2: DXVK Integration

• Create cmake/dxvk.cmake to fetch DXVK native libraries
• Configure imported target for d3d8 library
• Test DXVK linking and runtime loading

Phase 3: Dependency Management

• Create cmake/ffmpeg.cmake for Linux video playback
• Create cmake/freetype.cmake for font rendering
• Create cmake/openal.cmake for audio (if needed)
• Update vcpkg.json with Linux dependencies

Phase 4: Compiler Compatibility

• Add GCC/Clang compiler settings to cmake/compilers.cmake
• Add floating-point determinism flags for replay compatibility
• Add sanitizer options (ASan, UBSan) for development
• Fix hash_map → unordered_map (MSVC extension)
• Fix enum forward declaration compliance issues
• Fix vexing parse issues

Phase 5: Build Scripts

• Create scripts/linux-native-build.sh
• Create scripts/install-linux-deps.sh (distro detection)
• Create scripts/run-generals-linux.sh (game launcher)
• Update scripts/docker-build.sh header to clarify it produces Windows .exe

Phase 6: CI/CD

• Create .github/workflows/linux-native.yml
• Add GCC and Clang build matrix
• Add artifact upload for built binaries

Phase 7: Documentation

• Update README.md with Linux build instructions
• Document difference between Docker and native builds
• Document runtime requirements (Vulkan drivers, etc.)

Open Questions

1. SDL3 - Required or optional for windowing/input?
2. Audio - Miles via compatibility layer vs native OpenAL?
3. Priority - Zero Hour first, then Generals?
4. Minimum requirements - Vulkan 1.1+, glibc version?
5. Tools - Include WorldBuilder, W3DView in Linux build?

Files to Create

cmake/dxvk.cmake
cmake/ffmpeg.cmake
cmake/openal.cmake
cmake/freetype.cmake
cmake/platform-deps.cmake
cmake/game-install.cmake
scripts/linux-native-build.sh
scripts/install-linux-deps.sh
scripts/run-generals-linux.sh
.github/workflows/linux-native.yml

Files to Modify

CMakeLists.txt
CMakePresets.json
cmake/config.cmake
cmake/compilers.cmake
vcpkg.json
README.md
scripts/docker-build.sh

Related

• Fighter19 fork: https://github.com/Fighter19/CnC_Generals_Zero_Hour
• DXVK native: https://github.com/doitsujin/dxvk
• Detailed plan: tmp/native-linux.txt in this repo

---

/cc @xezon @feliwir

[jurassicLizard]

64-bit build is also highly recommended as a prerequisite for this to work as planned. which is also what figher19 did (as far as i had seen). first 64-bit then gradually we can have it native. I think that is the road of least resistance

[xezon]

OmniBlade — Yesterday at 21:26

My personal opinion is to look at getting fully 64bit Windows builds working first which requires replacing bink and miles and moving the renderer to at least dx9. This is also works towards a Linux port as the same changes are needed there regardless. Then off the top of my head, long type needs removing from the code base and winapi calls need replacing for input, window creation, font rendering various filesystem bits, registry, utf-16 handling and 3d rendering. There are probably more I'm forgetting too. The fighter19 fork is along with a lot of these to use as reference. However I'm inclined to say hold fire on working on these until vc6 is dropped, frustrating as that is for those wanting to crack on with supporting other platforms.

[xezon]

feliwir

One thing i wanted to mention regarding the GitHub issue: DXVK is not a solution for true cross-platform since it’s not available for macOS. It’s a temporary solution for Linux support at best. We‘ll still need a native GL or Vulkan backend

[jurassicLizard]

there is some overlap with linux-crosscompile : #2067
solving mingw-specific cross-compile issues will also partially solve many issues that involve gcc later when natively compiling for linux