About
SunDog: Frozen Legacy is a 1984 space trading and combat simulator video game, first released for the Apple II (version 1.0 in March 1984, version 2.0 in October 1984), with an enhanced version released for the Atari ST in December 1985. This project ports the 1985 Atari ST version of SunDog: Frozen Legacy to modern platforms using SDL2 for input and OpenGL ES 2+ for graphics. Since the original was written in UCSD Pascal compiled to p-code, the port implements its own p-system interpreter (a "P-Machine Emulator") in C rather than emulating the Atari ST or 68000 processor directly, with a handful of the original's assembly-language graphics routines reimplemented separately. It runs on Linux and Mac OS X and requires the player to supply their own 360K .st disk image of the original game, since no game resources or code are included for copyright reasons.
How it differs from the original
Aside from a few small hacks or improvements, the port aims to keep gameplay and graphics close to the original Atari ST version rather than reimagining it — a full re-imagining is instead being pursued separately by the unrelated Sundog Resurrection project. Unlike the original, it never writes back to the disk image during play.
Getting started
To play, supply your own legally obtained 360K .st disk image of the original Atari ST release (not a repacked version) and launch the program from the command line; gameplay is controlled entirely with the mouse, with a few keyboard shortcuts available for pausing and for saving or loading game state.
History
The port targets version IV.2.1 R3.4 of the p-system, a commercial runtime originally developed by SofTech; since no open-source implementation of that exact version existed, the author built a new interpreter for it from scratch rather than adapting the closest available open-source alternative, which implements an incompatible earlier version.
Media
Additional notes
- Retrospect
- The author has noted in retrospect that a lighter-weight approach emulating only the p-system's run-time level (skipping OS-level features the game doesn't actually use) would have sufficed, but calls the broader implementation "kind of cool" as a toy operating system in its own right.