Omega Race

Midway · 1981

by Daniel Ferrer

Details

Original hardware

Midway dual Z80

Romset

roms/omegrace.zip

Controls

The stick turns the ship (the cabinet's spinner). Button 1 fires, button 2 thrusts, button 3 inserts a coin, button 4 starts. On the web: Z, X, C, V and the arrow keys.

Analog controls

–

Last update

2026-11-08

Changelog

1. v1.12026-11-08
   • The romset can live in any folder of the card. The game looks in .roms/, then roms/, then searches the whole card, and remembers where it found it (.conf/<romset>.loc), so the next start goes straight there; if it is moved, it is searched for again.
   • Settings go in .conf/ and romsets in .roms/: the UVMC2's menu hides folders whose name starts with a dot, so the card shows only the games. A card set up before keeps everything: the old config/ and roms/ are still read, and nothing is written to them any more.
   • Without the romset on the card the screen says ROM FILE NOT FOUND and the name of the zip it wants.
2. v1.02026-11-05
   • First release of this port (the earlier 0.1a on this page was Ralf Kornmann's).
   • Sound through the jack: the board's two AY-3-8912s emulated at 1 MHz. AAE ran the sound Z80 but threw its writes away, and never raised the interrupt that hands it each command.
   • The level measured against MAME on its own sound CPU's writes replayed at the same instants (correlation 0.98).
   • The cabinet's switches as MAME ships them: 1 coin 1 credit, 3 ships, bonus at 100k. They read 1 coin 2 credits, 2 ships.
   • One picture a frame: the game asks for its vector list several times a frame and each went to the beam -- four copies of the attract's text, 2000-3700 strokes where the console draws about 500. It ran at 13 fps.
   • Bigger letters: the story, the score lines and the credits at 1.4 times the game's own size, each line about its own centre.
   • The playfield's corner and edge dots drawn, as MAME draws them, and the dim score box brighter: the game's 16 intensities spread from the tube's first visible step.
   • The picture is MAME's visible area, measured on a MAME snapshot, shown 4:3.
   • The board's clock: its interrupt, which paces the game and the sound CPU, at the board's 244 Hz. AAE fired it at 1000, so the attract's timers ran four times fast (its first screen change at 3.9 s, MAME's at 15.6; now 15.5).
   • Faster than the arcade by default: 60 Hz, the game at 1.5 times its speed -- at the cabinet's own pace the shots feel slow. REFRESH 40 in the options gives the cabinet's speed back. Both hold their rate on the console.
   • An options screen at start, after the Vectrex Studio intro: screen vertical or horizontal, refresh, brightness, controls (the buttons can be remapped, and the choice is saved) and calibration.