ForzaRecomp

An experimental Forza Horizon 1 static recompilation for Apple Silicon macOS, using ReXGlue. This is a development project. Build and module loading success do not establish playable gameplay. The current validation results are recorded in docs/status.md.

A title-specific Vulkan renderer is in development, with MoltenVK on Apple platforms and the existing Xenos renderer retained as the fallback. The first stage imports the supplied game's effects, tests shader translation, and maps graphics hook candidates. Native FH1 draws and a performance gain have not yet been demonstrated. See docs/native-renderer.md.

The project handles default.xex, XMediaFacade_default.xex, and SpeechFacade_default.xex as separate guest modules, and contains patches for ReXGlue's XEX allocation lifetime and code generation. The build uses Vulkan through MoltenVK for the Xbox 360 GPU backend. It translates PPC instructions to native C++; it does not recover the original developer source code.

Place your extracted disc files in FH1/, keeping the disc directory structure. Only the disc revision identified in config/disc.json is currently supported. The build verifies all three XEX hashes before applying address-specific configuration. Generated C++ and headers may be checked into this repository; they translate game instructions and do not contain the original developer source. The original XEXs and disc assets are still required to build and run. Game executable images, assets, and compiled game binaries are excluded.

With Xcode, CMake, Ninja, Git, and Python 3 installed:

python3 scripts/bootstrap_macos.py
sh scripts/build_macos.sh
sh scripts/run_macos.sh

Bootstrap downloads the checksum-pinned official macOS ARM64 SDK, clones its matching source revision, applies the patches, and builds the Release runtime, codegen tool and Xenos graphics plugin. It stages them with matching dependency libraries in .tools/rexglue-patched/. All downloaded dependencies and builds stay local. The first build can take several minutes. Use FH1_BUILD_JOBS=2 to reduce parallel compilation on machines with less memory.

The launch script keeps saves in out/user/ and diagnostics in out/logs/. Use FH1_GAME_DIRECTORY and FH1_USER_DIRECTORY to choose runtime locations. Additional ReXGlue command-line flags can be passed through the script. The host starts in a regular window on macOS. --fullscreen=true opts into fullscreen, which still needs further testing on Retina displays. For keyboard controller emulation, pass --mnk_mode=true; Space is A and Enter is Start. An SDL-compatible controller can also be used. The title's writable cache: device maps into out/user/cache/title/ by default. The disc mount stays read-only. The host enables gpu_allow_invalid_fetch_constants for FH1's unbound vertex-fetch references. An explicit runtime flag or user configuration takes precedence over this default.

For validation:

python3 -m unittest discover -s tests -v
python3 scripts/audit_public_tree.py
out/build/mac-arm64/fh1_xex_inspect FH1 out/images
out/build/mac-arm64/fh1_module_smoke FH1
out/build/mac-arm64/fh1_vmx_smoke
out/build/mac-arm64/fh1_wait_smoke
python3 scripts/smoke_boot.py --seconds 20

The inspector loads XEX data without running guest code and checks module allocations. The module smoke test checks native function dispatch and facade unload/reload without invoking DllMain. The bounded boot diagnostic launches the game and stops it after the interval; remaining alive is only a diagnostic result. Codegen output is checked for unresolved fatal calls and silently discarded branches before the build proceeds. The wait smoke tool checks event consumption, alertable callbacks and idle multi-object wait CPU usage without loading game files. The boot diagnostic writes a separate out/logs/boot-runtime.log and attempts guest framebuffer captures in out/logs/boot-frame.ppm and numbered snapshots every two seconds. These capture only the game output and stay ignored by Git. Pass additional diagnostic flags after --, for example python3 scripts/smoke_boot.py --seconds 60 -- --gpu_allow_invalid_fetch_constants=false. To inspect missing indirect entries, run python3 tools/find_indirect_candidates.py after dumping images with the inspector. Its reports require manual disassembly review and never change the translation configuration.

For a longer input diagnostic, set FH1_INPUT_SCRIPT to a local text file under out/ and pass --seconds 180. Each row contains start time and duration in seconds, hexadecimal controller buttons, right trigger (0–255), and left stick X (−32768–32767). For example, 38 0.5 0010 0 0 presses Start at 38 seconds. This opt-in driver feeds only guest controller 0. It sends no host keystrokes. Diagnostic intervals can be 1–600 seconds and end by intentionally stopping the game. For custom capture runs, FH1_CAPTURE_DELAY_MS delays the first capture and FH1_CAPTURE_INTERVAL_MS changes its interval (default 2000 ms). Delaying captures keeps GPU readback out of a CPU profile; normal launches create no capture worker unless FH1_CAPTURE_FRAME is set.

The patched runtime reuses presenter pipelines, backs off low-priority guest scheduler polling, and uses ARM vector operations for decoder permutations and shifts. Videos still use the translated WMV software decoder. The user reports slower onset of thermal throttling after the first two fixes; sustained thermal behavior remains under investigation.

.gitignore permits generated C++ and headers and excludes the disc tree, decrypted images, native binaries, SDK downloads, logs, saves, and credentials. The publication audit also catches ignored private files that were previously tracked. Run it before committing or publishing. A compiled game binary contains translated game instructions and is a private build artifact too.

docs/architecture.md explains the module design and runtime patches. docs/rendering.md records the world-composite fix and opt-in diagnostics. docs/profiling.md describes profiling 3D scenes on macOS. docs/ios-port.md describes the remaining iOS work. There is no validated iOS build target yet. The planned first-launch disc installer is described in docs/installer.md. ReXGlue's license is retained in patches/REXGLUE-LICENSE.txt.