One of Sega’s most enigmatic products, the canceled Sega VR headphones, finally appeared in “executable” form on Friday thanks to a team of specialists in preserving the history of games. It’s a tale of open ROM, searching for its source code and efforts to not only restore the game, but also adapt existing Genesis and Mega Drive emulators to translate virtual reality calls from today’s PC headsets.
The story, published on the Video Game Foundation’s website, begins with the discovery of a Dylan Mansfield ROM at Gaming Alexandria. The game in question, Nuclear fever, was one of four games announced for Sega VR, a headphone system designed to be included in the standard Genesis and Mega Drive consoles.
Not quite 72Hz …
Gamers of that era have probably heard of Sega VR, as the publisher’s PR pressure includes many mentions in gaming magazines, the public opening of Summer CES in 1993, and even a segment of ABC Nightline. But the ambitious device, which was supposed to hit the market for only $ 199, was quietly canceled, and former Sega president Tom Kalinske finally confirmed why: researchers found that the device made a huge percentage of testers suffer from headaches and dizziness.
Today’s finding partly explains where these symptoms of the disease probably come from. By breaking down and understanding the way Sega VR games communicate with Genesis and therefore Sega VR headphones, the Rich Whitehouse VGHF digital conservation head reveals the serious limitations of headphones: only 15 Hz refresh for stereoscopic images, as opposed to the 72 Hz minimum for Oculus Quest (not to mention the 90 Hz standard set by companies like HTC and Valve). In addition, Sega VR only translates the movement of the height and inclination of the users’ heads, not rolling – and this is on top of the system, which is already limited as a three-degree freedom (3DOF) system, requiring users to stay seated.
How did Whitehouse find out so much about Sega VR functionality so many years after the add-on disappeared? As it turns out, the daily search for a bug in the history of Mansfield games includes requests to various developers from the 90’s for any old prototypes or code that may have been stored in the drawer. In the case of Kenneth Hurley, who is working on Nuclear fever as part of Futurescape Productions, he went one up and sent to Mansfield a CD-ROM dated August 6, 1994 – which miraculously did not succumb to a little rot.
Whitehouse stepped in at this point to figure out how to compile the rest of the almost complete code (called “final” but not “final retail”), which required a combination of C and assembly. Among Whitehouse’s findings: the written code only works on some hardware revisions of Genesis and Mega Drive based on how it handles horizontal and vertical scrolling of sprites and assets, which requires minor adjustments. Also, the metadata in the code hinted at a winter CES 1994 showing Sega VR, which never materialized.
He could use SVP
Although the open CD-ROM lacks key Sega VR files (which Whitehouse says would be called VR.DOC and VR.TXT), Whitehouse still managed to figure out how the system would work with 16-bit consoles. The Sega VR IO would revolve around the second port of the console controller, although Whitehouse’s explanation does not clarify whether the console’s output port would be redirected to the Sega VR headphones or how this would work. In addition, the Sega VR headset would receive two 30Hz images that Nuclear fever it would then be further split with its 15fps refresh.
While figuring out how to do it Nuclear fever working as a VR experience in 2020, Whitehouse spoke with the game’s original lead programmer, Kevin McGrath, who confirmed that his team had done a lot of work on Sega VR without actually having test headphones – and they came up with a test that had the video output of the game flashes between two computer monitors to see how it can do the same with two images on headphones. Another VR-based game developer, Alex Smith, confirmed that the Outlaw Racing team never even got a prototype headset before its project was preserved.
The rest of Whitehouse’s work revolved around building OpenVR support in a working Genesis emulator, which included, among other things, making serious assumptions about how Sega VR panels were positioned and shaped, and then fixed the oddities of 1994. to work more efficiently on modern computers (partly to reduce the potential motion sickness of a Genesis-era game locked at 15fps). The resulting emulator and a pair are compiled Nuclear fever ROMs are available for download and testing from the VGHF article.
Ars Technica has tested this combination of emulator and ROM on a Windows 10 PC running the HP Reverb G2 headset, and I can confirm that the game plays as well as you might expect: it’s a basic 3D tank game, like the arcade classics of Atari Battle zone has been rebuilt with sprites and palettes from the Genesis era, but it’s all a sprite field scam, not the elementary polygonal stuff of the early ’90s Fox Star or Virtua Fighter. (Sega VR games obviously don’t accumulate with additional cassette chips like Sega’s SVP used in Genesis’s version of Virtual competitions.)
The resulting restored game is by no means a revolutionary experience. Still, the combined efforts of all of the above have brought life back to a game whose original version is likely to make you sick. Fortunately, modern hardware (and its enterprising users) can revive canceled games in ways that won’t make game history buffs throw their cookies, and this is a testament to the modern game-saving movement.
See the whole intriguing story, full of ridiculous technical information, at the Video Game History Foundation.