Gamepad: buttons property

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The Gamepad.buttons property of the Gamepad interface returns an array of gamepadButton objects representing the buttons present on the device.

Each entry in the array is 0 if the button is not pressed, and non-zero (typically 1.0) if the button is pressed. Each gamepadButton object has two properties: pressed and value:

  • The pressed property is a boolean indicating whether the button is currently pressed (true) or unpressed (false).
  • The value property is a floating point value used to enable representing analog buttons, such as the triggers on many modern gamepads. The values are normalized to the range 0.0 – 1.0, with 0.0 representing a button that is not pressed, and 1.0 representing a button that is fully pressed.

Value

An array of gamepadButton objects.

Examples

The following code is taken from my Gamepad API button demo (you can view the demo live, and find the source code on GitHub.) Note the code fork — in Chrome Navigator.getGamepads needs a webkit prefix and the button values are stores as an array of double values, whereas in Firefox Navigator.getGamepads doesn't need a prefix, and the button values are stored as an array of GamepadButton objects; it is the GamepadButton.value or GamepadButton.pressed properties of these we need to access, depending on what type of buttons they are. In this simple example I've just allowed either.

js
function gameLoop() {
  let a = 0;
  let b = 0;
  if (navigator.webkitGetGamepads) {
    const gp = navigator.webkitGetGamepads()[0];

    if (gp.buttons[0] === 1) {
      b--;
    } else if (gp.buttons[1] === 1) {
      a++;
    } else if (gp.buttons[2] === 1) {
      b++;
    } else if (gp.buttons[3] === 1) {
      a--;
    }
  } else {
    const gp = navigator.getGamepads()[0];

    if (gp.buttons[0].value > 0 || gp.buttons[0].pressed) {
      b--;
    } else if (gp.buttons[1].value > 0 || gp.buttons[1].pressed) {
      a++;
    } else if (gp.buttons[2].value > 0 || gp.buttons[2].pressed) {
      b++;
    } else if (gp.buttons[3].value > 0 || gp.buttons[3].pressed) {
      a--;
    }
  }

  ball.style.left = `${a * 2}px`;
  ball.style.top = `${b * 2}px`;

  const start = rAF(gameLoop);
}

Specifications

Specification
Gamepad
# dom-gamepad-buttons

Browser compatibility

BCD tables only load in the browser

See also

Using the Gamepad API