This is not a major issue, but it definitely impacts user experience. It has been noticed while playing the USA locale of both Quake for Saturn and Sonic Jam collection.
Prerequisites:
1. SSF emulator
Official website (Japanese): http://www.geocities.jp/mj3kj8o5/ssf/index.html
Official website translated in English: https://translate.google.com/translate?sl=ja&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.geocities.jp%2Fmj3kj8o5%2Fssf%2Findex.html&edit-text=&act=url
The issue is reproducible with both Ver0.12 beta R4 and test version.
2. DirectX End-User Runtime Web Installer: Download DirectX End-User Runtime Web Installer from Official Microsoft Download Center
3. Quake and Sonic Jam for Sega Saturn.
4. A disk image mounting software. SSF can only read from real CDs. This is needed only if have game as disk image.
I will not enter in large details about the issue since I attached 2 videos. I'll just list the issues to easily spot them while watching the video:
Issues on Quake 1:
-strange lines over weapon and sky that repeatedly appear and disappear;
-if you pause game while looking at the sky a parallelepiped-shaped figure is drawned. It should be invisible.
Issues on Sonic Jam:
-strange lines appear when browsing the digital manual. Reproducible with any game in collection.
-strange lines also appear for a split second when entering Sonic World, when sky is visible (smaller video).
Notes:
-In the videos I used a batch file I created to automatically and quickly switch games;
-I tested this issue with a large number of drivers: 9.17.10.2867, 9,17.10.3071, 9.17.10.3347, 10.18.10.3621, 10.18.10.3945, 10.18.10.3958 and latest 10.18.10.4061.
-This issue does not occur on 2nd generation Intel Core processors for example.
-SSF is not open-source unfortunately.
Getting started with SSF:
-Open SSF and navigate in menu to Option - Option;
-In Peripheral tab
1. select CD Drive where the game is inserted (changes take effect after SSF restart);
2. select the Area code matching the games locales;
3. Data cartridge is not needed.
-In controller tab:
1. Hit redefine under Player 1:A. This maps keyboard keys to Saturn buttons. These mappings can be adjusted per game, if that game is running when redefine is initiated.
Buttons effects in-game:
1,Quake 1:
Dpad Up: Walk forward (field) / previous option (menu)
Dpad Down: Backpedal (field) / next option (menu)
Dpad left: Turn left (field) / adjust selected option to previous value (menu)
Dpad right: Turn right (field) / adjust selected option to next value (menu)
Button A: Fire (field) / Confirm selection (menu)
Button B: Jump (field) / Cancel selection or back (menu)
Button C: unused
Button X: Center View (field) / unused (menu)
Button Y: Previous weapon (field) / unused (menu)
Button Z: Next weapon (field) / unused (menu)
L trigger: Lateral step left (field) / unused (menu)
R trigger: Lateral step right (field) / unused (menu)
Button Start: Open / close menu, pause / resume
-Buttons combinations. Only apply on field
Button X+Dpad Down=Look Up
Button X+Dpad Up=Look Down
Don't ask me why they are switched like this.
2.Sonic Jam (Sonic games)
Dpad Up: Walk forward (field) / previous option (menu)
Dpad Down: Backpedal (field) / next option (menu)
Dpad left: Turn left (field) / adjust selected option to previous value (menu) / previous game (game selection screen)
Dpad right: Turn right (field) / adjust selected option to next value (menu) / next game (game selection screen)
Button A: Jump (field) / Confirm selection (menu)
Button B: Jump (field) / Cancel selection (menu)
Button C: Jump (field)
Button A|
Dpad Down+Button B|(repeated press)=Spin Dash
Button C|
There are a few more but they are not relevant for this issue report anyway.
3. Sonic Jam (Sonic World)
Press Start to enter Sonic World.