Copyright © 2022 W3C® (MIT, ERCIM, Keio, Beihang). W3C liability, trademark and permissive document license rules apply.
The Gamepad specification defines a low-level interface that represents gamepad devices.
This section describes the status of this document at the time of its publication. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at https://www.w3.org/TR/.
This is a work in progress.
This document was published by the Web Applications Working Group as a Working Draft using the Recommendation track.
Publication as a Working Draft does not imply endorsement by W3C and its Members.
This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
This document was produced by a group operating under the W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
This document is governed by the 2 November 2021 W3C Process Document.
This section is non-normative.
Some user agents have connected gamepad devices. These devices are desirable and suited to input for gaming applications, and for "10 foot" user interfaces (presentations, media viewers).
Currently, the only way for a gamepad to be used as input would be to emulate mouse or keyboard events, however this would lose information and require additional software outside of the user agent to accomplish emulation.
Meanwhile, native applications are capable of accessing these devices via system APIs.
The Gamepad API provides a solution to this problem by specifying interfaces that allow web applications to directly act on gamepad data.
Interfacing with external devices designed to control games has the potential to become large and intractable if approached in full generality. In this specification we explicitly choose to narrow scope to provide a useful subset of functionality that can be widely implemented and broadly useful.
Specifically, we choose to only support the functionality required to support gamepads. Support for gamepads requires two input types: buttons and axes. Both buttons and axes are reported as analog values, buttons ranging from [0..1], and axes ranging from [-1..1].
While the primary goal is support for gamepad devices, supporting these two types of analog inputs allows support for other similar devices common to current gaming systems including joysticks, driving wheels, pedals, and accelerometers. As such, the name "gamepad" is exemplary rather than trying to be a generic name for the entire set of devices addressed by this specification.
We specifically exclude support for more complex devices that may also be used in some gaming contexts, including those that that do motion sensing, depth sensing, video analysis, gesture recognition, and so on.
This interface defines an individual gamepad device.
WebIDL[Exposed=Window, SecureContext]
interface Gamepad {
  readonly attribute DOMString id;
  readonly attribute long index;
  readonly attribute boolean connected;
  readonly attribute DOMHighResTimeStamp timestamp;
  readonly attribute GamepadMappingType mapping;
  readonly attribute FrozenArray<double> axes;
  readonly attribute FrozenArray<GamepadButton> buttons;
};
      The algorithms used to communicate with the system typically complete asynchronously, queuing work on the gamepad task source.
        Instances of Gamepad are created with the internal slots described
        in the following table:
      
| Internal slot | Initial value | Description (non-normative) | 
|---|---|---|
| [[connected]] | false | A flag indicating that the device is connected to the system | 
| [[timestamp]] | undefined | The last time data for this Gamepadwas updated | 
| [[axes]] | An empty sequence | A sequence of doublevalues representing the current state
            of axes exposed by this device | 
| [[buttons]] | An empty sequence | A sequence of GamepadButtonobjects representing the
            current state of buttons exposed by this device | 
| [[exposed]] | false | A flag indicating that the Gamepadobject has been exposed to
            script | 
| [[axisMapping]] | An empty ordered map | Mapping from unmapped axis index to an index in the axesarray | 
| [[axisMinimums]] | An empty list | A list containing the minimum logical value for each axis | 
| [[axisMaximums]] | An empty list | A list containing the maximum logical value for each axis | 
| [[buttonMapping]] | An empty ordered map | Mapping from unmapped button index to an index in the buttonsarray | 
| [[buttonMinimums]] | An empty list | A list containing the minimum logical value for each button. | 
| [[buttonMaximums]] | An empty list | A list containing the maximum logical value for each button | 
id attribute
        An identification string for the gamepad. This string identifies the brand or style of connected gamepad device.
            The exact format of the id string is left unspecified.
            It is RECOMMENDED that the user agent select a string that
            identifies the product without uniquely identifying the device. For
            example, a USB gamepad may be identified by its idVendor and
            idProduct values. Unique identifiers like serial numbers or
            Bluetooth device addresses MUST NOT be included in the
            id string.
          
index attribute
        Navigator. When multiple gamepads
          are connected to a user agent, indices MUST be assigned on a
          first-come, first-serve basis, starting at zero. If a gamepad is
          disconnected, previously assigned indices MUST NOT be reassigned to
          gamepads that continue to be connected. However, if a gamepad is
          disconnected, and subsequently the same or a different gamepad is
          then connected, the lowest previously used index MUST be reused.
        connected attribute
        
            Indicates whether the physical device represented by this object is
            still connected to the system. When a gamepad becomes unavailable,
            whether by being physically disconnected, powered off or otherwise
            unusable, the connected attribute MUST be set to
            false.
          
            The connected getter steps are:
          
[[connected]].
            timestamp attribute
        
            The timestamp allows the author to determine the last
            time the axes or buttons attribute for this
            gamepad was updated. The value MUST be set to the current high resolution time each time the system receives new button or axis input values from the device. If no data has been received
            from the hardware, timestamp MUST be the current high resolution time at the time when the Gamepad was first made
            available to script.
          
            User agents SHOULD set a minimum resolution of gamepad's
            timestamp attribute to 5 microseconds, following
            [HR-TIME]'s clock resolution recommendation.
          
            The timestamp getter steps are:
          
[[timestamp]].
            mapping attribute
        
            The mapping in use for this device. If the user agent has knowledge
            of the layout of the device, then it SHOULD indicate that a mapping
            is in use by setting mapping to the corresponding
            GamepadMappingType value.
          
To select a mapping for a gamepad device, run the following steps:
standard".
            axes attribute
        Array of values for all axes of the gamepad. All axis values MUST be linearly normalized to the range [-1.0 .. 1.0]. If the controller is perpendicular to the ground with the directional stick pointing up, -1.0 SHOULD correspond to "forward" or "left", and 1.0 SHOULD correspond to "backward" or "right". Axes that are drawn from a 2D input device SHOULD appear next to each other in the axes array, X then Y. It is RECOMMENDED that axes appear in decreasing order of importance, such that element 0 and 1 typically represent the X and Y axis of a directional stick. The same object MUST be returned until the user agent needs to return different values (or values in a different order).
            The axes getter steps are:
          
buttons attribute
        Array of button states for all buttons of the gamepad. It is RECOMMENDED that buttons appear in decreasing importance such that the primary button, secondary button, tertiary button, and so on appear as elements 0, 1, 2, ... in the buttons array. The same object MUST be returned until the user agent needs to return different values (or values in a different order).
            The buttons getter steps are:
          
[[buttons]].
            When the system receives new button or axis input values, run the following steps:
Gamepad object representing the
          device that received new button or axis input values.
          To update gamepad state for gamepad, run the following steps:
[[timestamp]] to now.
          Navigator object.
          [[hasGamepadGesture]] is false and
          gamepad contains a gamepad user gesture:
            [[hasGamepadGesture]] to
              true.
              [[gamepads]]:
                null:
                    [[exposed]] to
                      true.
                      [[timestamp]] to
                      now.
                      Document; otherwise
                      null.
                      null and is fully active, then queue a task on the gamepad task source to fire an event named gamepadconnected
                      at gamepad's relevant global object using
                      GamepadEvent with its gamepad
                      attribute initialized to connectedGamepad.
                      To map and normalize axes for gamepad, run the following steps:
unsigned long values
          representing the most recent logical axis input values for each axis
          input of the device represented by gamepad.
          [[axisMapping]][rawAxisIndex].
              [[axisMinimums]][rawAxisIndex].
              [[axisMaximums]][rawAxisIndex].
              [[axes]][axisIndex] to be
              normalizedValue.
              To map and normalize buttons for gamepad, run the following steps:
unsigned long values
          representing the most recent logical button input values for each
          button input of the device represented by gamepad.
          [[buttonMapping]][rawButtonIndex].
              [[buttonMinimums]][rawButtonIndex].
              [[buttonMaximums]][rawButtonIndex].
              [[buttons]][mappedIndex].
              [[value]] to
              normalizedValue.
              
                  If the button has a digital switch to indicate a pure pressed
                  or released state, set button.[[pressed]]
                  to true if the button is pressed or false if it is not
                  pressed.
                
                  Otherwise, set button.[[pressed]] to
                  true if the value is above the button press threshold
                  or false if it is not above the threshold.
                
                  If the button is capable of detecting touch, set
                  button.[[touched]] to true if the
                  button is currently being touched.
                
                  Otherwise, set button.[[touched]] to
                  button.[[pressed]].
                
          A new Gamepad representing a connected gamepad device is
          constructed by performing the following steps:
        
Gamepad instance:
            id attribute to an
              identification string for the gamepad.
              index attribute to the
              result of selecting an unused gamepad index for gamepad.
              mapping attribute to the
              result of selecting a mapping for the gamepad device.
              [[connected]] to true.
              [[timestamp]] to the
              current high resolution time.
              [[axes]] to the result of
              initializing axes for gamepad.
              [[buttons]] to the result of
              initializing buttons for gamepad.
              To select an unused gamepad index for gamepad, run the following steps:
Navigator object.
          [[gamepads]] − 1.
          [[gamepads]][gamepadIndex] is
              null, then return gamepadIndex.
              null to navigator.[[gamepads]].
          [[gamepads]] − 1.
          To initialize axes for gamepad, run the following steps:
[[axisMinimums]] to a list of
          unsigned long values with size equal to inputCount
          containing minimum logical values for each of the axis inputs.
          [[axisMaximums]] to a list of
          unsigned long values with size equal to inputCount
          containing maximum logical values for each of the axis inputs.
          Otherwise:
[[axisMapping]][rawInputIndex] to
                      canonicalIndex.
                      Otherwise, append rawInputIndex to unmappedInputList.
[[axisMapping]][rawInputIndex] to
              axisIndex.
              To initialize buttons for a gamepad, run the following steps:
[[buttonMinimums]] to be a list of
          unsigned long values with size equal to inputCount
          containing minimum logical values for each of the button inputs.
          [[buttonMaximums]] to be a list of
          unsigned long values with size equal to inputCount
          containing maximum logical values for each of the button inputs.
          Otherwise:
[[buttonMapping]][rawInputIndex]
                      to canonicalIndex.
                      Otherwise, append rawInputIndex to unmappedInputList.
[[buttonMapping]][rawInputIndex]
              to buttonIndex.
              GamepadButton to
          buttons.
          This enum defines the set of known mappings for a Gamepad.
WebIDLenum GamepadMappingType {
  "standard",
  "xr-standard",
};
      ""
        "standard"
        "xr-standard"
        getGamepads() MUST NOT report a mapping of
          "xr-standard".
        WebIDL[Exposed=Window, SecureContext]
interface GamepadEvent: Event {
  constructor(DOMString type, GamepadEventInit eventInitDict);
  [SameObject] readonly attribute Gamepad gamepad;
};
      gamepad
        gamepad attribute provides access to the
          associated gamepad data for this event.
        WebIDLdictionary GamepadEventInit : EventInit {
  required Gamepad gamepad;
};
        gamepad member
          Gamepad associated with this event.
          Each device manufacturer creates many different products and each has unique styles and layouts of buttons and axes. It is intended that the user agent support as many of these as possible.
Additionally there are de facto standard layouts that have been made popular by game consoles. When the user agent recognizes the attached device, it is RECOMMENDED that it be remapped to a canonical ordering when possible. Devices that are not recognized should still be exposed in their raw form.
        There is currently one canonical layout, the Standard
        Gamepad. When remapping, the indices in axes and
        buttons should correspond as closely as possible to the
        physical locations in the diagram below. Additionally,
        mapping SHOULD be set to "standard".
      
The Standard Gamepad buttons are laid out in a left cluster of four buttons, a right cluster of four buttons, a center cluster of three buttons, and a pair of front facing buttons on the left and right side of the gamepad. The four axes of the "Standard Gamepad" are associated with a pair of analog sticks, one on the left and one on the right. The following table describes the buttons/axes and their physical locations.
An axis input represents a Standard Gamepad axis if it reports the input value for a thumbstick axis, the thumbstick is located in approximately the same location as the corresponding Standard Gamepad thumbstick, and the orientation of the axis (up-down or left-right) matches the orientation of the Standard Gamepad axis. If there are multiple axes that represent the same Standard Gamepad axis, then the user agent SHOULD select one to be the Standard Gamepad axis and assign a different index to the other axis.
A button input represents a Standard Gamepad button if it reports the input value for a button or trigger, and the button or trigger is located in approximately the same location as the corresponding Standard Gamepad button.
If an axis or button input represents a Standard Gamepad axis or button, then its canonical index is the index of the corresponding Standard Gamepad axis or button.
| Button/Axis | Location | 
|---|---|
| buttons[0] | Bottom button in right cluster | 
| buttons[1] | Right button in right cluster | 
| buttons[2] | Left button in right cluster | 
| buttons[3] | Top button in right cluster | 
| buttons[4] | Top left front button | 
| buttons[5] | Top right front button | 
| buttons[6] | Bottom left front button | 
| buttons[7] | Bottom right front button | 
| buttons[8] | Left button in center cluster | 
| buttons[9] | Right button in center cluster | 
| buttons[10] | Left stick pressed button | 
| buttons[11] | Right stick pressed button | 
| buttons[12] | Top button in left cluster | 
| buttons[13] | Bottom button in left cluster | 
| buttons[14] | Left button in left cluster | 
| buttons[15] | Right button in left cluster | 
| buttons[16] | Center button in center cluster | 
| axes[0] | Horizontal axis for left stick (negative left/positive right) | 
| axes[1] | Vertical axis for left stick (negative up/positive down) | 
| axes[2] | Horizontal axis for right stick (negative left/positive right) | 
| axes[3] | Vertical axis for right stick (negative up/positive down) | 
This section is non-normative.
        The example below demonstrates typical access to gamepads. Note the
        relationship with the
        requestAnimationFrame() method.
      
function runAnimation() {
    window.requestAnimationFrame(runAnimation);
    for (const pad of navigator.getGamepads()) {
      // todo; simple demo of displaying pad.axes and pad.buttons
      console.log(pad);
    }
}
window.requestAnimationFrame(runAnimation);requestAnimationFrame()
        
        
          Interactive applications will typically be using the
          requestAnimationFrame() method to drive
          animation, and will want coordinate animation with user gamepad
          input. As such, the gamepad data should be polled as closely as
          possible to immediately before the animation callbacks are executed,
          and with frequency matching that of the animation. That is, if the
          animation callbacks are running at 60Hz, the gamepad inputs should
          also be sampled at that rate.
        
When a gamepad becomes available on the system, run the following steps:
null.
        null and is not allowed to use the
        "gamepad" permission, then abort these steps.
        Gamepad representing the
            gamepad.
            Navigator object.
            [[gamepads]][gamepad.index]
            to gamepad.
            [[hasGamepadGesture]] is true:
              [[exposed]] to true.
                null and is fully active, then fire an event named gamepadconnected at
                gamepad's relevant global object using GamepadEvent
                with its gamepad attribute initialized to
                gamepad.
                
        User agents implementing this specification must provide a new DOM
        event, named gamepadconnected. The corresponding event MUST be of
        type GamepadEvent and MUST fire on the Window object.
      
        A user agent MUST dispatch this event type to indicate the user has
        connected a gamepad. If a gamepad was already connected when the page
        was loaded, the gamepadconnected event SHOULD be dispatched when
        the user presses a button or moves an axis.
      
When a gamepad becomes unavailable on the system, run the following steps:
Gamepad representing the
        unavailable device.
        [[connected]] to false.
            Document; otherwise null.
            [[exposed]] is true and document
            is not null and is fully active, then fire an event named gamepaddisconnected at gamepad's relevant global object using GamepadEvent with its
            gamepad attribute initialized to gamepad.
            Navigator object.
            [[gamepads]][gamepad.index]
            to null.
            [[gamepads]] is not empty and the last item of
            navigator.[[gamepads]] is null, remove
            the last item of navigator.[[gamepads]].
            
        User agents implementing this specification must provide a new DOM
        event, named gamepaddisconnected. The corresponding event MUST be
        of type GamepadEvent and MUST fire on the Window object.
      
        When a gamepad is disconnected from the user agent, if the user agent has previously dispatched a gamepadconnected event for that
        gamepad to a Window, a gamepaddisconnected event MUST be
        dispatched to that same Window.
      
        More discussion needed, on whether to include or exclude axis and
        button changed events, and whether to roll them more together
        ("gamepadchanged"?), separate somewhat ("gamepadaxischanged"?), or
        separate by individual axis and button.
      
        This specification extends the WindowEventHandlers interface mixin
        from HTML to add event handler IDL attributes to facilitate the
        event handler registration.
      
WebIDLpartial interface mixin WindowEventHandlers {
  attribute EventHandler ongamepadconnected;
  attribute EventHandler ongamepaddisconnected;
};
    
        This specification defines a policy-controlled feature identified by
        the string "gamepad". Its default allowlist is 'self'.
      
          A document’s permissions policy determines whether
          any content in that document is allowed to access
          getGamepads(). If disabled in any document, no content
          in the document will be allowed to use
          getGamepads(), nor will the gamepadconnected and
          gamepaddisconnected events fire.
        
As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.
The key words MUST, MUST NOT, RECOMMENDED, SHOULD, and SHOULD NOT in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
This section is non-normative.
The following people contributed to the development of this document.Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in:
Referenced in: