What used to be wishful thinking is now reality, thanks to Joe, aka SEGARPGFAN, who is bringing more SEGA Saturn games online for those using NetLink and Xband modem cartridges.
Throughout the week he’s been sharing online beta builds for Touge King, Last Bronx, Die Hard Arcade and Herc’s Adventures in the SHIRO! Discord server. All four games can now connect to the latest matchmaking server through the modem, with Touge King even doing away with the two-player split-screen for a true dual screen experience.
“Thank Catapult for the Xband drivers and ChatGPT for being scary effective at doing what I ask,” Joe said.
Side-by-side Touge King. The time of day mismatch is being worked on.
The games are patched with a modified JP Xband interface, with the new drivers reducing latency. Profiles can now use real names — no longer needing to be named mp or sp — and save taunts, and also now have separate dial and wait commands. This makes connecting online easier than ever, with the games dialing out their unique three-digit codes automatically. Joe said that these games are really close to release quality but need more real world testing.
“The interface changes these games use for Xband can be ported to all the JP games, and the latency tolerance can be ported to both US and JP,” he said. “I’m mostly waiting on some really long-distance testing to call it good to go.”
He said the modified JP Xband driver can queue more inputs at the expense of higher input lag. “Controller inputs are always delayed, or buffered, to account for connection latency,” Joe said. “The games negotiate the lowest safe amount of buffer based on the connection. That’s why playing with someone closer to you feels better — you have lower input lag.
“If the latency exceeds what it can buffer however, the game will slow down to buy time. Previously, it didn’t take much to hit this point. The drivers have been modified to roughly double the available buffer. That means in the case of a higher latency connection, you can still get full speed gameplay, but with higher input lag instead of slowdown. I think most people will find that an acceptable tradeoff.”
Joe said startup polling also checks a sequence number which fixes a condition where the stock driver could fall back to its maximum queue depth.
“The startup buffer negotiation could sometimes fall back to the maximum with the stock code,” he said. “When I increased the buffer it exposed this behavior. Some test connections had really high input lag. The check now includes a sequence number check and allows some pings to fail without immediately setting things to the maximum.
“Games that use RNG have RNG drift checks that will halt the game if drift is detected. Some games use random number generation for certain things like item spawning, enemy movement etc. That needs to by synced or the games will quickly diverge. There’s a mechanism for syncing that and periodically checking for drift, halting the game if drift is detected.”
This is all a work in progress, but the results have been absolutely astonishing so far. New co-op experiences over the Saturn modem have been especially popular with the current testers. If you’d like to join in with the testing, head over to SHIRO! Discord’s saturn_online chat channel where you can find the downloads and share any issues you come across.
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