======= TRACK BALL =======

<fc #ff0000>**THIS WAS THE HARDEST PART OF GETTING EVERYTHING RUNNING AND I SPENT  3+ DAYS WORKING THE ISSUE**</fc>

<fc #ffa500>**YOU WILL NEED A KEYBOARD**</fc>

  * NOTE 1: we're going to do everything command line, but if you need retroarch menu, 
    * it's <SCROLL + F1>
  * NOTE 2: We need these instructions because by default, Missile Command and Tempest are looking for LIGHTGUN, not mouse, so we need to enable the mouse.

Score 1 for Gemini.. ChatGPT just fell apart.

Before we start, and before firing up the game, 
  * we bring up the game in our MAME menu, 
  * then long press Button 1 to bring up a menu. 
  * Move down to "Advanced Game Options". 
    * Emulator will be LIBRETRO:MAME for Phoenix and Missle Command, 
    * and LIBRETRO: MAME078PLUS for Centipede.

==== Step 1: Identifying the Hardware ====

The system sees every USB device (Keyboard, PS3 controller, Xinmotec, Trackball) and gives it a "Mouse Index" number.

  * Command: cat /proc/bus/input/devices
  * Discovery: You found the Cypress Semiconductor (the trackball) and saw Handlers=mouse0.
  * Result: This told us your magic number is Index 0.

==== Step 2: Enabling the "Engine" (.opt file) ====

The Emulator Core (MAME) has to be told that it is allowed to use a mouse at all.


  * Location: /userdata/system/configs/retroarch/config/MAME/missile.opt
  * Key Setting: mame_mouse_enable = "enabled"
  * Result: This turned on the "ears" of the emulator so it could hear mouse signals.


<code>
[root@BATOCERA /userdata/…troarch/config/MAME]# tail missile.opt
mame_media_type = "rom"
mame_mouse_enable = "enabled"
mame_read_config = "enabled" 
</code>
==== Step 3: Mapping the "Plumbing" (.cfg file) ====

Because the menu wasn't saving, we manually created a "Game Override" file. This tells RetroArch exactly which hardware to plug into the "Player 1" slot.

  *  Creation: We created a new text file at: /userdata/system/configs/retroarch/config/MAME/missile.cfg
  *  The Code: You added these two critical lines:
    * input_player1_mouse_index = "0" (Points to the Trackball)
    * input_libretro_device_p1 = "3" (Tells MAME to treat Player 1 as a "Mouse" device)

<code>
[root@BATOCERA ~]# tail /userdata/system/configs/retroarch/config/MAME/missile.cfg
input_player1_mouse_index = "0"
input_libretro_device_p1 = "3"
</code>
==== Step 4: Applying this to Tempest (The Spinner) ====

Tempest uses a spinner, but in MAME, a spinner is just the X-axis (left/right) of a mouse. To fix Tempest without doing all that work again:

  *  Navigate to the same folder: /userdata/system/configs/retroarch/config/MAME/
    * Copy missile.cfg and Paste it as tempest.cfg.
    * Copy missile.opt and Paste it as tempest.opt.

 Launch Tempest. It will now use the same "Index 0" logic.

Summary Table for Future Reference
|File Type	|Purpose	|Key Setting |
|.opt	| Core Options	| mame_mouse_enable = "enabled" |
|.cfg	| Input Mapping	| input_player1_mouse_index = "0" |
|.cfg	| Device Type	| input_libretro_device_p1 = "3" |


<code>
[root@BATOCERA /userdata/…troarch/config/MAME]# ls -al
total 36
drwxr-xr-x 2 root root  4096 Jan 29 14:01 .
drwxr-xr-x 4 root root  4096 Jan 28 18:01 ..
-rw-r--r-- 1 root root 11402 Jan 29 13:42 MAME.cfg
-rw-r--r-- 1 root root    63 Jan 29 13:50 missile.cfg
-rw-r--r-- 1 root root   817 Jan 29 09:15 missile.opt
-rw-r--r-- 1 root root    63 Jan 29 14:01 tempest.cfg
-rw-r--r-- 1 root root   817 Jan 29 14:01 tempest.opt
</code>

==== Step 5: Map the keys in the game ====

  * Using the keyboard, press "Tab" and a menu will pop up.
  * You will use the arrow keys to navigate
  * Press 'Z' to choose a menu item, in this case, "Input Assignments (this system)"
  * "Del"  anything for P1 Button 1,2,3  and P2 Button 1,2,3 and TrackBall Analog
  * Press 'Z' for Button 1. When presented with '< >' press the button on your console that you want
  * Repeat for buttons 2 and 3
  * Move down to "Trackball X Analog" and press 'Z'
  * Move your trackball in the X axis
  * Repeat for "Trackball Y Analog" moving along the Y axis
  * Move down to "Return to Previous Menu" and choose "Analog Input Adjustments"
  * Currently (subject to change or change as needed), all values are 30. Only "Trackball X Reverse" is set to <fc #ff0000>off.</fc>
  * Back out of each menu when you're done. The settings will automatically save. Do the above for each game using LIBRETRO (in my case, Missile Command and Tempest)