forked from hybridgroup/gobot
/
joystick_driver.go
192 lines (171 loc) · 4.6 KB
/
joystick_driver.go
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package joystick
import (
"encoding/json"
"fmt"
"io/ioutil"
"time"
"github.com/hybridgroup/go-sdl2/sdl"
"github.com/hybridgroup/gobot"
)
var _ gobot.Driver = (*JoystickDriver)(nil)
// JoystickDriver represents a joystick
type JoystickDriver struct {
name string
interval time.Duration
connection gobot.Connection
configPath string
config joystickConfig
poll func() sdl.Event
halt chan bool
gobot.Eventer
}
// pair is a JSON representation of name and id
type pair struct {
Name string `json:"name"`
ID int `json:"id"`
}
// hat is a JSON representation of hat, name and id
type hat struct {
Hat int `json:"hat"`
Name string `json:"name"`
ID int `json:"id"`
}
// joystickConfig is a JSON representation of configuration values
type joystickConfig struct {
Name string `json:"name"`
GUID string `json:"guid"`
Axis []pair `json:"axis"`
Buttons []pair `json:"buttons"`
Hats []hat `json:"Hats"`
}
// NewJoystickDriver returns a new JoystickDriver with a polling interval of
// 10 Milliseconds given a JoystickAdaptor, name and json button configuration
// file location.
//
// Optinally accepts:
// time.Duration: Interval at which the JoystickDriver is polled for new information
func NewJoystickDriver(a *JoystickAdaptor, name string, config string, v ...time.Duration) *JoystickDriver {
d := &JoystickDriver{
name: name,
connection: a,
Eventer: gobot.NewEventer(),
configPath: config,
poll: func() sdl.Event {
return sdl.PollEvent()
},
interval: 10 * time.Millisecond,
halt: make(chan bool, 0),
}
if len(v) > 0 {
d.interval = v[0]
}
d.AddEvent("error")
return d
}
// Name returns the JoystickDrivers name
func (j *JoystickDriver) Name() string { return j.name }
// Connection returns the JoystickDrivers connection
func (j *JoystickDriver) Connection() gobot.Connection { return j.connection }
// adaptor returns joystick adaptor
func (j *JoystickDriver) adaptor() *JoystickAdaptor {
return j.Connection().(*JoystickAdaptor)
}
// Start and polls the state of the joystick at the given interval.
//
// Emits the Events:
// Error error - On button error
// Events defined in the json button configuration file.
// They will have the format:
// [button]_press
// [button]_release
// [axis]
func (j *JoystickDriver) Start() (errs []error) {
file, err := ioutil.ReadFile(j.configPath)
if err != nil {
return []error{err}
}
var jsontype joystickConfig
json.Unmarshal(file, &jsontype)
j.config = jsontype
for _, value := range j.config.Buttons {
j.AddEvent(fmt.Sprintf("%s_press", value.Name))
j.AddEvent(fmt.Sprintf("%s_release", value.Name))
}
for _, value := range j.config.Axis {
j.AddEvent(value.Name)
}
for _, value := range j.config.Hats {
j.AddEvent(value.Name)
}
go func() {
for {
event := j.poll()
if event != nil {
if err = j.handleEvent(event); err != nil {
gobot.Publish(j.Event("error"), err)
}
}
select {
case <-time.After(j.interval):
case <-j.halt:
return
}
}
}()
return
}
// Halt stops joystick driver
func (j *JoystickDriver) Halt() (errs []error) {
j.halt <- true
return
}
// HandleEvent publishes an specific event according to data received
func (j *JoystickDriver) handleEvent(event sdl.Event) error {
switch data := event.(type) {
case *sdl.JoyAxisEvent:
if data.Which == j.adaptor().joystick.InstanceID() {
axis := j.findName(data.Axis, j.config.Axis)
if axis == "" {
return fmt.Errorf("Unknown Axis: %v", data.Axis)
}
gobot.Publish(j.Event(axis), data.Value)
}
case *sdl.JoyButtonEvent:
if data.Which == j.adaptor().joystick.InstanceID() {
button := j.findName(data.Button, j.config.Buttons)
if button == "" {
return fmt.Errorf("Unknown Button: %v", data.Button)
}
if data.State == 1 {
gobot.Publish(j.Event(fmt.Sprintf("%s_press", button)), nil)
}
gobot.Publish(j.Event(fmt.Sprintf("%s_release", button)), nil)
}
case *sdl.JoyHatEvent:
if data.Which == j.adaptor().joystick.InstanceID() {
hat := j.findHatName(data.Value, data.Hat, j.config.Hats)
if hat == "" {
return fmt.Errorf("Unknown Hat: %v %v", data.Hat, data.Value)
}
gobot.Publish(j.Event(hat), true)
}
}
return nil
}
func (j *JoystickDriver) findName(id uint8, list []pair) string {
for _, value := range list {
if int(id) == value.ID {
return value.Name
}
}
return ""
}
// findHatName returns name from hat found by id in provided list
func (j *JoystickDriver) findHatName(id uint8, hat uint8, list []hat) string {
for _, lHat := range list {
if int(id) == lHat.ID && int(hat) == lHat.Hat {
return lHat.Name
}
}
return ""
}