AmiGTA1 - A native AmigaOS 68k port of Grand Theft Auto is in the works

Amiga owners here's another interesting news story to talk about, as developer Grzegorz Korycki, who was mentioned by us previously for his work on OpenTTD for AmigaOS 68k, is working on a port called AmiGTA1. This ambitious project is a ground-up reimplementation of the 1997 classic Grand Theft Auto engine specifically optimized for native AmigaOS 68k systems. Unlike modern hardware emulators or additional hardware like the PiStorm or Vampire, AmiGTA targets authentic classic setups, requiring a 68020 processor or higher paired with either AGA or RTG graphics. The release adheres strictly to legal boundaries by containing no copyrighted game code or assets. Instead, players must supply their own original PC files, which an included utility converts directly on the Amiga.

The initial v0.0.2 alpha release already delivers an impressive technical foundation, rendering Liberty City in a gap-free 2.5D perspective while achieving a smooth 59.8 frames per second on the developer's calibrated machine. In its current state, players can run around the bustling streets, carjack unsuspecting drivers, and speed through traffic utilizing the original game's real-time physics, vehicle mass, and AI routing. While core mechanics like missions, weapons, audio, police presence, and the infamous wanted levels are not yet wired up, the project serves as an incredible proof-of-concept for what the classic Amiga is truly capable of achieving.

How it was made :

• The engine is written from scratch as native 68020 code — fixed point throughout, sin/cos lookup tables, built around c2p — rather than translated from anything. The original's behaviour is the specification: how fast a car accelerates, how far it slides, how the AI picks a route and when it brakes, how much a collision pushes and how much it spins. Those numbers are the game's own rather than values tuned by hand until the result looked plausible, which is why the comments in native/gta_traffic.c and native/gta_vehphys.c read the way they do.
• The data layer follows the official DMA CityScape Data Structure spec and the MIT-licensed Carnage3D project.
• The platform layer — AGA screen handling, c2p, RTG, Paula audio, the soft-float fixes for the m68k GCC — is carried over from the same author's openttd_amiga_68k and OpenXcom ports.
• There is no floating point anywhere in the game code. On this target it is not an optimisation but a hazard: Kickstart 3.1's mathieeesingbas.library has broken single-precision multiply and divide entries on FPU-less machines, and 68040/68060 FPUs are partly trap-emulated anyway.

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