Autofire Plugin

Introduction

The autofire plugin allows you to simulate repeatedly pressing an emulated button by holding down a key or button combination. This can help people with certain disabilities or injuries play shooting games, and may help reduce the risk of repetitive strain injuries (or keyboard damage).

To configure the autofire plugin, activate the main menu (press Tab during emulation by default), select Plugin Options, and then select Autofire. Configured autofire buttons for the current system are listed, along with their repetition rates and activation hotkeys (initially there will be no autofire buttons configured). Select an autofire button to change settings, or choose Add autofire button to set up a new autofire button. See Autofire buttons settings for details on setting up an autofire button. You can delete an autofire button by highlighting it in the menu and pressing the UI Clear key (Del/Delete/Forward Delete on the keyboard by default).

Autofire settings are saved in the autofire folder in the plugin data folder (see the homepath option). A file is created for each system with autofire buttons configured, named according to the system’s short name (or ROM set name), with the extension .cfg. For example, autofire settings for Super-X will be saved in the file superx.cfg in the autofire folder in your plugin data folder. The autofire settings are stored in JSON format.

Autofire buttons settings

The options for adding a new autofire button or modifying an existing autofire button are the same.

Select Input to set the emulated button that you want to simulate pressing repeatedly. Currently, only player buttons are supported. Typically you’ll set this to the primary fire button for shooting games. This is most often P1 Button 1 or the equivalent for another player, but it might have have a different name. On Konami’s Gradius games, P1 Button 2 is the primary fire button.

Select Hotkey to set the input combination you’ll use to activate the autofire button. This can be any combination that MAME supports for activating a digital input.

On frames and Off frames are the number of consecutive emulated video frames that the emulated button will be held and released for, respectively. Adjust the value with the UI Left/Right keys, or click the arrows. Press the UI Clear key to reset the values to one frame. Lower values correspond to pressing the button at a faster rate. Depending on how fast the system reads inputs, you may need higher numbers than 1 for the system to recognise the button being released and pressed again (e.g. 2 on frames and 2 off frames works for Alcon). Experiment with different values to get the best effect.

When adding a new autofire button, there is a Cancel option that changes to Create after you set the input and hotkey. Select Create to finish creating the autofire button and return to the list of autofire buttons. The new autofire button will be added at the end of the list. Press the UI Cancel key (Escape/Esc on the keyboard by default), or select Cancel before setting the input/hotkey, to return to the previous menu without creating the new autofire button.

When modifying an existing autofire button, select Done or press the UI Cancel key to return to the list of autofire buttons. Changes take effect immediately.

Notes and potential pitfalls

Autofire buttons act as if they’re wired in parallel with MAME’s regular inputs. This means that if you set the activation hotkey for an autofire button to a button or key that’s also assigned to one of the emulated inputs directly, you may get unexpected results. Using Gradius as an example:

  • Suppose you set button 1 on your controller to fire, and set an autofire hotkey to button 1 as well. Holding the button down to shoot will not trigger the autofire effect: the button will never be released as you’re holding the non-autofire button 1 down. This will also happen if you set a different button as autofire (say, button 3 in this case), and hold button 1 down while also pressing button 3.

  • If you set button 3 on your controller to autofire and assign button 3 to powerup as well, you will trigger the powerup action every time you grab a powerup because the powerup button is also being held down along with the autofire button.

It is suggested you choose input combinations for autofire hotkeys that are not assigned to any other emulated inputs in the system.

Autofire is not necessarily desirable in all situations. For example using autofire in Super-X with the blue “lightning” weapon equipped at high power levels will only produce a single beam, greatly reducing the weapon’s effectiveness. The fire button must be held down to produce all beams. Some shooting games (e.g. Raiden Fighters) require the primary fire button to be held down for a charged special attack. This means it’s often necessary to have a non-autofire input for the primary fire button assigned to play effectively.