Saturn MiSTer Core Gets Mouse Support

The Saturn MiSTer core has seen a flurry of updates in the last week, partially thanks to an unexpected source — another developer.

Rattboi did a lot of work to add mouse support, and the core’s usual developer, Sergiy Dvodnenko, aka SRG320, merged his updates into the main unstable branch.

Earlier in the month and in late August, Dvodnenko fixed a background issue affecting Princess Crown and used a homebrew audio-testing tool to make improvements to emulating the Saturn’s sound chip.

The updated core must be manually applied after downloading it from the official MiSTer Discord server’s unstable nightlies channel.

The core’s GitHub lists the specific updates:

SCSP:

• fix the phase calculation (Bug! sounds)
• fix Alternative loop mode (Sakura Taisen 2 long counter sound)
• some fixes for accuracy (scsptest)
• fix Monitor register update (X-Men vs. Street Fighter,Sega Rally Championship regression)
• some fixes for accuracy (scsptest)
  SCU:
• fix IO access (Digital Monster Ver. S)
• cycle accurate B-BUS port to SCSP (scsptest)
  VDP1:
• fix update User clipping coordinate (Albert Odyssey)
• fix sprite rendering (Battle Garegga regression)
  VDP2:
• fix the Sprite window (Idol Janshi Suchie Pai II)
• fix NBG2/3 rendering when reduction mode is enabled for NBG0/1 (Princess Crown)
• fix Shadow priority (Legend of Oasis, Princess Crown)
• fix the Vertical Counter value (Senkutsu Katsuryu Taisen: Chaos Seed)
  SH7604 core
• fix TE flag clearing (Black Dawn crashes)
  Mouse support from Rattboi
• 3 buttons work, mapped as L->A, R->B, M->C
• The start button still only comes from the controller
• Use either the usb mouse or joystick mouse, and either one works — Swap between to your heart’s delight
• Small refactors to keep ps2 mouse code together
• More cleanup/retab
• Remove some refactor mess w/ mouse buttons

Mouse support brings new functionality to dozens of games , even some light gun games , which is particularly helpful considering MiSTers typically are played on HDTVs that aren’t compatibility with light gun controllers.

In fact, Rattboi said he worked on mouse support for the core for Policenauts, a game that has light gun shooter segments.

“[I] was playing Policenauts with my friend and he was like ‘[this seems like it should be a mouse game,'” Rattboi said on the MiSTer server.

Meanwhile, the sound chip testing tool was developed by Celeriyacon that Dvodnenko first used last month paid dividends almost immediately.

While the tool itself has increased how precisely it measures emulation of the SCSP chip, and the MiSTer core is not yet passing one of those new metrics, it’s nonetheless improved since last month.