ROLLER

August 6, 2026 · View on GitHub

Roller logo

This project aims to implement all the functionality of the 1995 game Whiplash/Fatal Racing in a way that builds and runs on modern PCs. Where necessary, DOS-specific functions are substituted with SDL and Windows/Unix equivalents. For instruction-matching decomp, see https://github.com/FatalDecomp/ROLLER-matching

Play

Play ROLLER in your browser with the bundled freeware demo, or import an image of a legally owned retail disc for the full game. No install is required.

Native installations require assets from a retail copy of the game. Download the latest native version from the releases page and extract it wherever you want. On initial launch, select a CD image (CUE/BIN or ISO) to extract the assets. Press the ` key to access additional settings.

About

Debug symbol dump generated with wdump, part of: https://github.com/open-watcom/open-watcom-v2

Useful tool in generating nice asm output with symbols from wdump applied: https://github.com/fonic/wcdatool

Directions on how to use wcdatool and get remote debugging working with open watcom: https://www.youtube.com/watch?v=bG9tEZOSrQg

Note: wdump symbol offsets do not account for DOS4GW.EXE. Load FATAL.EXE_split_dos4g_payload.exe (FATAL.EXE with DOS4GW.EXE split off, generated by wcdatool) into Ida/Ghidra to have matching symbol offsets.

Hashes of executables used for decomp:

FATAL.EXE

md5: 812EEE1404ECDFD87FF765281DF89720
SHA256: 7789768C0A6CDC213EAF7B1AD8CC125531EB3FE7C213ECCAC6188E58F428687E

FATAL.EXE_split_dos4g_payload.exe

md5: 05C2B0730641663133D76DD2CA552B4C
SHA256: A4AD4131DBBFF9884DA4687D8B579B81117E6D23525950D942DF2DF585E2A11E

External Dependencies Used:

SDL3.2.22: https://github.com/libsdl-org/SDL
SDL_Image3.2.4: https://github.com/libsdl-org/SDL_image
WildMIDI 0.4.6: https://github.com/Mindwerks/wildmidi
libcdio-2.3.0: https://github.com/libcdio/libcdio
Nuklear 4.13.2: https://github.com/Immediate-Mode-UI/Nuklear

Build

Video instructions: https://www.youtube.com/watch?v=QEDGhvvZ9XU

Clone the repository

git clone https://github.com/zizin13/roller.git
cd roller

Install prerequisites

Zig 0.15.2

The easiest way to install is to use mise:

mise install

Build and run the project

Using default settings

zig build run

A custom data folder

zig build -Dassets-path=/path/to/fatdata run

Prepare the playable demo assets

The browser build uses the hash-pinned Whiplash demo selected by ADR 0002. zig build web automatically downloads, verifies, and extracts only its FATDATA tree before packaging it at /demo/fatdata:

zig build web

For an offline build, prepare the tree from a previously downloaded copy, then point the web build at it. The explicit tree is verified against the same E3.S2 file count, size, and tree SHA-256 before emcc runs:

python scripts/fetch_demo_assets.py --source /path/to/whipdemo.zip
zig build web -Ddemo-assets-path=zig-out/fatdata-demo

The bundle contains roller-<sha256>.data plus a deterministic bundle-manifest.json with raw byte sizes and SHA-256 hashes.

Testing

Rendering snapshot tests

git lfs install        # one-time, the baselines are LFS-tracked
zig build test-snapshots

Captures the indexed framebuffer of every intro replay at hand-picked ticks and runs git diff against the checked-in baselines. Any pixel change shows up as a tracked-file diff that GitHub renders as a side-by-side image diff in PRs.

On a non-canonical host (anything other than the pinned reference machine) use -Dscratch to capture into zig-out/snapshot-scratch/ without touching the LFS-tracked baselines.

See tests/snapshots/README.md for the full developer workflow (blessing intentional pixel changes, troubleshooting, etc.) and docs/adr/0001-rendering-snapshot-tests.md for the policy decisions.