lr-mame2010 lightgun instructions

[StormedBubbles]

The master branch of this fork of the lr-mame2010 core allows lightgun usage (i.e., Sinden lightguns) for up to 4 players. The method of achieving this is credited to Mr. Lightgun in his lr-mame2016 fork. I also added the same features to my fork of lr-mame2015.

I picked lr-mame2010 and lr-mame2015 to focus on because there are some lightgun games that work best in these cores within the libretro framework (on an overclocked Raspberry Pi 4B):

2010:

• Ghoul Panic (sound issues; investigating possible solutions)
• Golgo 13 (sound issues; investigating possible solutions)
• Golgo 13 Kiseki no Dandou (sound issues; investigating possible solutions)
• Point Blank 2

2015:

• Judge Dredd (a Raspberry Pi 4B seems to need to be overclocked to get full speed in this game)
• Rapid Fire
• Great Guns

Here is the way it works:

• The lightgun coordinates are mapped to each player's RIGHT analog axes
• In the MAME Tab menu's input section, the user sets the lightgun axes to the corresponding user's RIGHT analog axes. You may find it easier to directly edit a per-game MAME config file. For example, the X axis of lightgun input for player 1 would be input as JOYCODE_1_RXAXIS
• In the mame.ini, which resides in your rompath/mame2010/ini folder, you MUST set joystick_deadzone 0 and joystick_saturation 1 in order to get fluid and accurate gun tracking
• Button 1 for each player is usually the trigger (Great Guns is an exception. Player 2's trigger is Player 1's Button 2)
• Games that require you to shoot while pointing away from the screen to reload should work properly when you fire while the cursor (which can be disabled in the MAME Tab menu) is on the edge of the game screen

This is a roundabout way of getting multiple mice to work in lr-mame2010, so only one MAME input's worth of mouse buttons is recognized. You will have to map triggers and other buttons for other players to non-mouse buttons. The code by Mr. Lightgun for lr-mame2016 was set up as such specifically for Sinden lightguns, which allow the user to remap buttons as desired.

As part of getting all of this to work, I had to add analog controls for 4 players. If that is useful, I can submit a pull request upstream to add analog controls. The lightgun portions are probably best left here since they rely on stealing an analog stick from each controller. I suppose these same principles can be used to add support for multiple trackballs & spinners in the same way that the lightgun inputs were added. I could create a branch of my fork specific to mouse inputs for multiple mice, if anyone would find that useful.

I am an amateur with coding, but I hope that this allows users on Raspberry Pi and other, similar computers to enjoy games they otherwise thought they couldn't play properly 😃