joystick

Documentation

Overview

Package joystick provides utilities for querying and reacting to joystick or gamepad inputs.

Index

• Constants
• func Init() error
• func WaitForJoysticks(pollRate time.Duration) (joyCh <-chan *Joystick, cancel func())
• type Joystick
  • func GetJoysticks() []*Joystick
  • func (j *Joystick) Close() error
  • func (j *Joystick) GetState() (*State, error)
  • func (j *Joystick) ID() uint32
  • func (j *Joystick) Listen(opts *ListenOptions) (cancel func())
  • func (j *Joystick) Prepare() error
  • func (j *Joystick) Vibrate(left, right uint16) error
• type ListenOptions
• type State
• type Triggerer

Constants

const (
	Change          = "JoystickChange"
	ButtonDown      = "ButtonDown"
	ButtonUp        = "ButtonUp"
	RtTriggerChange = "RtTriggerChange"
	LtTriggerChange = "LtTriggerChange"
	RtStickChange   = "RtStickChange"
	LtStickChange   = "LtStickChange"
	Disconnected    = "JoystickDisconnected"
)

Events

Functions

func Init

func Init() error

Init calls any os functions necessary to detect joysticks

func WaitForJoysticks

func WaitForJoysticks(pollRate time.Duration) (joyCh <-chan *Joystick, cancel func())

WaitForJoysticks will regularly call GetJoysticks so to send signals on the output channel when new joysticks are connected to the system. Call `cancel' to close the channel and stop polling.

Types

type Joystick

type Joystick struct {
	Handler  Triggerer
	PollRate time.Duration
	// contains filtered or unexported fields
}

A Joystick represents a (usually) physical controller connected to the machine. It can be listened to to obtain button / trigger states of the controller and propagate changes through an event handler.

func GetJoysticks

func GetJoysticks() []*Joystick

GetJoysticks returns all known active joysticks.

func (*Joystick) Close

func (j *Joystick) Close() error

Close closes any operating system resources backing this joystick's signals

func (*Joystick) GetState

func (j *Joystick) GetState() (*State, error)

GetState returns the current button, trigger, and analog stick state of the joystick

func (*Joystick) ID

func (j *Joystick) ID() uint32

ID returns which player this joystick is associated with

func (*Joystick) Listen

func (j *Joystick) Listen(opts *ListenOptions) (cancel func())

Listen causes the joystick to send its inputs to its Handler, by regularly querying GetState. The type of events returned can be specified by options. If the options are nil, only JoystickChange events will be sent.

func (*Joystick) Prepare

func (j *Joystick) Prepare() error

Prepare allocates any operating system resources needed to read signals for the joystick.

func (*Joystick) Vibrate

func (j *Joystick) Vibrate(left, right uint16) error

Vibrate triggers vibration on a joystick (if it is supported).

type ListenOptions

type ListenOptions struct {
	// Each boolean dictates given event type(s) will be sent during Listen
	// "JoystickChange": *State
	JoystickChanges bool
	// Whenever any button is changed:
	// "ButtonDown": *State
	// "ButtonUp": *State
	GenericButtonPresses bool
	// "($buttonName)Up/Down": *State
	// e.g.
	// "AButtonUp": *State
	// "XButtonDown:" *State
	ButtonPresses bool
	// "RtTriggerChange": *State
	// "LtTriggerChange": *State
	TriggerChanges bool
	// "RtStickChange": *State
	// "LtStickChange": *State
	StickChanges bool
}

ListenOptions can be passed into a joystick's Listen method to change what events will be propagated out.

type State

type State struct {
	// Frame advances every time the State changes,
	// Making it easier to tell if the state has not changed
	// since the last poll.
	Frame uint32
	// ID is the joystick ID this state is associated with
	ID uint32
	// There isn't a canonical list of buttons (yet), because
	// this can be so dependent on controller type. To get a list of expected
	// buttons for a joystick, this map can be checked after a single GetState().
	// The package will ensure that the keyset of this map will never change for
	// a given joystick variable. True = Pressed/Down. False = Released/Up.
	// Todo: ensure the above guarantee
	Buttons  map[string]bool
	TriggerL uint8
	TriggerR uint8
	StickLX  int16
	StickLY  int16
	StickRX  int16
	StickRY  int16
}

State represents a snapshot of a joystick's inputs

type Triggerer

type Triggerer interface {
	Trigger(string, interface{})
}

A Triggerer can either be an event bus or event CID, allowing joystick triggers to be listened to globally or sent to particular entities.