GunCon2-MiSTer

Resources for using the Namco GunCon 2 lightgun with the MiSTer FPGA

The official distributions of MiSTer's linux kernel (zImage_dtb) and main executable (MiSTer) now include special handling for CRT lightguns and driver support for the GunCon 2 and GunCon 3, so no custom files are needed - you just need the latest official distributions and the right hardware.

Setup instructions

You will need:

• a Namco GunCon 2 (compatibles/clones should work)
• a standard-definition CRT TV
• a means of tapping your GunCon's RCA cable into your MiSTer's video sync signal (see step 4 below)

Optionally, for calibration, you will also need:

• an installed copy of the 240p Test Suite for the core you will run
• a keyboard with a working F10 key

1. Run the downloader script on your MiSTer to keep its main executable and Linux kernel up to date.

2. Plug in the GunCon 2. The USB connector can be plugged into any of your data-capable USB ports (i.e., not the "POWER ONLY" one on the USB hub.) The yellow RCA connector needs to be connected to a composite sync signal. If you are using component video, you can tap into the Luma (green) cable. If you are using RGB, you need to be using composite sync, and the gun needs to be tapped into the composite sync signal. If you are using RGB with Sync on Green (SOG) enabled, the green line should also work.

You should now be able to use your GunCon 2 as a controller on the MiSTer. The ideal calibration settings for the gun will vary for each display, and for each core.

Calibration instructions

To calibrate the gun for a particular core, follow these steps:

4. Open a core (e.g., SNES), and load the 240p Test Suite.

5. Use the 240p Test Suite's "White and RGB Screen" pattern to display a full white screen.

6. Open the MiSTer OSD and press F10 on a keyboard. A lightgun calibration menu should appear.

7. Using the menu, aim at the extreme edges of the screen, then press A on the left side of the gun to calibrate that edge. (Note: The menu will prompt you to press "Trigger"; press "A" instead.) Your goal is to get the most extreme numbers you can without the gun losing sight of the screen. When doing this with the GunCon 2, BE CAREFUL not to calibrate the min and max of the same axis to the same value (e.g., both offscreen); if you do, your MiSTer will divide by zero when applying your calibration, and will crash. If this happens, just delete your calibration files from /config.

8. You should now be calibrated. To confirm, try enabling the core's lightgun crosshair (if it has one) and moving around the white screen. Note that calibration is per-core, so you'll need to calibrate separately in NES, PSX, the main menu, etc.

GunCon 2 Performance on MiSTer

Overall, the GunCon 2 is an accurate and precise lightgun with relatively little jitter. It requires a certain level of screen brightness in order to detect the CRT beam; some consoles' lightguns were designed for IR tracking or very tight CRT flash timing, which gives the GunCon 2 some trouble.

• NES (Zapper): Good. There are some issues with hit detection on black screens, such as the Duck Hunt menu, but in-game performance has tested mostly solid.

• Master System (Light Phaser): Okay. Works well for brighter games. Darker games, like certain sections of Shooting Gallery, have trouble.

• SNES (Super Scope, Justifier): Good. You may need to brighten your screen for some games, but most Super Scope games are already bright enough to work well. All SNES Justifier games have been thoroughly tested, except for Lethal Enforcers.

• Genesis (Menacer, Justifier): Okay. You may need to brighten your screen for some games.

• PSX: Performance is good overall, though there are some detection issues when shooting at dark areas of the screen.

  Note: The GunCon in the PSX core uses the following buttons from the standard gamepad:

  • Circle: maps to Trigger
  • Start: maps to A
  • Cross: maps to B

  So, map your GunCon 2's trigger to Circle, your A button to Start, and your B button to Cross. (For the other buttons, feel free to either map them as desired or skip them - they will be ignored when the core is emulating the GunCon 1.)

• Saturn (Stunner): Core is still in development and does not yet have lightgun support.

Notes on using the GunCon 2, and on this driver/setup

• Like the Wiimote, this gun can report its coordinates as a mouse (with throttling applied) and as a raw joystick. It will work much better as a raw joystick. Hence, when setting up specific cores, choose the "Joy" options for aiming.

• The self-compiled kernel here works fine for the most part, but it may not work properly with some devices (for example, some WiFi dongles.) These issues should no longer exist once the next official kernel release incorporates GunCon 2 support. In the meantime, be sure to keep your official kernel image available, so that you can swap back to it if needed.

• If you accidentally severely miscalibrate the gun for a core, the core may crash or not start up. If this happens, or if you want to retry calibration for another reason, look for the gun calibration files in /config on your SD card, and delete them.

• The GunCon 2 is capable of reading a 480p screen, but this driver is not yet capable of that, so it functions only with standard-definition CRTs. NTSC and PAL should both be fine.

Sinden Lightgun Support

If you have a Sinden Lightgun and are interested in using it on the MiSTer FPGA, this driver can make that possible with the following additional hardware:

• Raspberry Pi 4
• Arduino Micro
• Open-Source Scan Converter (OSSC)

Follow the instructions at https://sindenlightgun.miraheze.org/wiki/OG_Console_Setup_Guide to set your Sinden Lightgun up to emulate a GunCon 2 using the Raspberry Pi and Arduino. Use your MiSTer to output over analog or direct video, and use the OSSC to apply a Sinden-compatible white border to the screen.

Using the Sinden as an emulated GunCon 2 should give excellent performance on all lightgun-compatible cores, without any of the tracking issues or brightness dependence of the original GunCon 2, and without the need for a CRT.

Credits

This GunCon 2 driver was originally created by beardypig with the assistance of Rubén Tomás and the RGB-Pi development team. You can find the main version of the driver at https://github.com/beardypig/guncon2 . Many thanks to them for developing an excellent driver, and for making it open-source and publicly available so that as many people as possible can enjoy some good CRT shooting.

Thanks to sonik_br, Freddo, wickerwaka, and alanswx for testing, technical advice, and encouragement.