Grand Prix Circuit (1988) - Native 64-bit Recompilation

Grand Prix Circuit (1988) - Native 64-bit Recompilation

A modern, standalone, native 64-bit recompilation and enhanced port of the legendary Formula 1 simulator Grand Prix Circuit (Accolade / Distinctive Software, 1988).

Written in Rust, this port runs natively on modern operating systems without emulation layers like DOSBox, adding true 60 FPS scanline motion interpolation, real-time Commodore 64 (VIC-II / SID 6581) mode switching, and multi-platform support.

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Key Features

• Native 64-bit Port: Built in Rust for Windows (x64), Linux (x64 / Steam Deck), and macOS (Apple Silicon M-Series).
• 60 FPS Spatial Motion Interpolation (F9):
  • Eliminates the original 1988 engine's 20 FPS judder using 2D scanline optical flow displacement.
  • Curves, kerbs, and road lines physically translate across the screen at 60 FPS with zero motion blur, zero ghosting, and zero transparency.
  • Dashboard and cockpit remain 100% stationary, sharp, and vibration-free.
  • Press F9 in real time to toggle between [ 60 FPS INTERPOLATION ] and [ 20 FPS CLASSIC ].
• Integrated Commodore 64 Mode (F10):
  • Hot-toggle between MS-DOS (EGA 16-color + PC Speaker audio) and Commodore 64 (VIC-II palette + MOS 6581 SID sound synthesis).
  • Cycle-accurate MOS 6502 CPU + MOS 6581 SID emulator playing Kris Hatlelid's iconic C64 soundtrack.
• In-Memory EXEPACK Support:
  • Automatically depacks the commercial retail DOS executable (GPEGA.EXE) directly in memory. No external unpacker or Python scripts required.
• Low Latency & High Performance:
  • Optimized CPU execution budget completely eliminates frame drops in crowded corners.

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Legal Notice / Disclaimer

This project is a clean-room source port and reverse-engineering effort created strictly for interoperability, modern system compatibility, and historical preservation.

This repository does NOT contain any copyrighted game binaries, images, tracks, sounds, or disk images. To play the game, you must provide the game data files from your own legally purchased copy of Grand Prix Circuit (e.g. from original 5.25"/3.5" floppy disks or a digital backup).

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How to Play

1. Download Pre-Built Release

Download the archive for your operating system from the Releases tab:

• Windows: GrandPrixCircuit_Windows_x64.zip
• Linux / Steam Deck: GrandPrixCircuit_Linux_x64.tar.gz
• macOS (Apple Silicon M1/M2/M3/M4): GrandPrixCircuit_macOS_Silicon.zip

Extract the contents into a folder on your computer.

2. Supply Your Original Game Files

Copy the following files from your original MS-DOS game into the extracted folder (or inside a subfolder named gprix2/):

• GPEGA.EXE (or GPEGA_UNP.EXE)
• All *.PES and *.PCS track/car assets (e.g. STATUS.PES, CAR1.PES, DETROIT.PES, MONACO.PES, etc.)
• (Optional, for C64 Mode audio): Grand_Prix_Circuit.sid

3. Launch & Controls

Run GrandPrixCircuit.exe (Windows) or ./GrandPrixCircuit (Linux / macOS).

Key	Action
F9	Toggle 60 FPS Motion Interpolation / 20 FPS Classic
F10	Toggle MS-DOS Mode (EGA/Speaker) / Commodore 64 Mode (VIC-II/SID)
Up Arrow / NumPad 8	Accelerate
Down Arrow / NumPad 2	Brake
Left / Right Arrow	Steer
Space / Left Shift	Shift Up
Enter / Left Ctrl	Shift Down
Escape	Pause Game / Return to Menu

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Building from Source

Prerequisites

• Rust toolchain (edition 2021, stable)

Linux Build Dependencies

On Debian, Ubuntu, or SteamOS:

sudo apt-get update && sudo apt-get install -y libasound2-dev libx11-dev libxcursor-dev pkg-config

On Fedora / RHEL:

sudo dnf install -y alsa-lib-devel libX11-devel pkgconf-pkg-config

On Arch Linux:

sudo pacman -S --noconfirm alsa-lib libx11 pkgconf

Compiling

# Clone the repository
git clone https://github.com/UgaTEC/grand-prix-circuit-recomp.git
cd grand-prix-circuit-recomp

# Build in release mode
cargo build --release --manifest-path gprix_recomp/Cargo.toml

# Or use the platform helper scripts:
./build_linux.sh   # Linux
./build_macos.sh   # macOS

The compiled binary will be located at gprix_recomp/target/release/gprix_recomp (or gprix_recomp.exe on Windows).

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License

This project is licensed under the MIT License.
Grand Prix Circuit is a registered trademark / copyright of Accolade / Distinctive Software (1988).