ebiten: Add VibrateGamepad and implement this on browsers

Updates #1452

examples/vibrate/main.go

@@ -33,6 +33,7 @@ const (
 
 type Game struct {
 	touchIDs   []ebiten.TouchID
+	gamepadIDs []ebiten.GamepadID
 }
 
 func (g *Game) Update() error {
@@ -42,11 +43,33 @@ func (g *Game) Update() error {
 		ebiten.Vibrate(200 * time.Millisecond)
 	}
 
+	g.gamepadIDs = g.gamepadIDs[:0]
+	g.gamepadIDs = ebiten.AppendGamepadIDs(g.gamepadIDs)
+	for _, id := range g.gamepadIDs {
+		for b := ebiten.GamepadButton0; b <= ebiten.GamepadButtonMax; b++ {
+			if !inpututil.IsGamepadButtonJustPressed(id, b) {
+				continue
+			}
+			// TODO: Test weak-magnitude.
+			op := &ebiten.VibrateGamepadOptions{
+				Duration:        200 * time.Millisecond,
+				StrongMagnitude: 1,
+				WeakMagnitude:   0,
+			}
+			ebiten.VibrateGamepad(id, op)
+			break
+		}
+	}
+
 	return nil
 }
 
 func (g *Game) Draw(screen *ebiten.Image) {
-	ebitenutil.DebugPrint(screen, "Touch the screen to vibrate the screen.")
+	msg := "Touch the screen to vibrate the screen."
+	if len(g.gamepadIDs) > 0 {
+		msg += "\nPress a gamepad button to vibrate the gamepad."
+	}
+	ebitenutil.DebugPrint(screen, msg)
 }
 
 func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {

internal/driver/input.go

@@ -14,6 +14,10 @@
 
 package driver
 
+import (
+	"time"
+)
+
 type GamepadID int
 
 type TouchID int
@@ -36,5 +40,6 @@ type Input interface {
 	StandardGamepadAxisValue(id GamepadID, button StandardGamepadAxis) float64
 	StandardGamepadButtonValue(id GamepadID, button StandardGamepadButton) float64
 	TouchPosition(id TouchID) (x, y int)
+	VibrateGamepad(id GamepadID, duration time.Duration, strongMagnitude float64, weakMagnitude float64)
 	Wheel() (xoff, yoff float64)
 }

internal/uidriver/glfw/input.go

@@ -23,6 +23,7 @@ package glfw
 import (
 	"math"
 	"sync"
+	"time"
 	"unicode"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/driver"
@@ -409,6 +410,10 @@ func (i *Input) IsStandardGamepadButtonPressed(id driver.GamepadID, button drive
 	return gamepaddb.IsButtonPressed(g.guid, button, gamepadState{&g})
 }
 
+func (i *Input) VibrateGamepad(id driver.GamepadID, duration time.Duration, strongMagnitude float64, weakMagnitude float64) {
+	// TODO: Implement this (#1452)
+}
+
 func init() {
 	// Confirm that all the hat state values are the same.
 	if gamepaddb.HatUp != glfw.HatUp {

internal/uidriver/js/input_js.go

@@ -17,11 +17,14 @@ package js
 import (
 	"encoding/hex"
 	"syscall/js"
+	"time"
 	"unicode"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/driver"
 )
 
+var object = js.Global().Get("Object")
+
 var (
 	stringKeydown    = js.ValueOf("keydown")
 	stringKeypress   = js.ValueOf("keypress")
@@ -60,6 +63,8 @@ type pos struct {
 }
 
 type gamepad struct {
+	value js.Value
+
 	name          string
 	mapping       string
 	axisNum       int
@@ -310,7 +315,9 @@ func (i *Input) updateGamepads() {
 		}
 
 		id := driver.GamepadID(gp.Get("index").Int())
-		g := gamepad{}
+		g := gamepad{
+			value: gp,
+		}
 		g.name = gp.Get("id").String()
 		g.mapping = gp.Get("mapping").String()
 
@@ -506,3 +513,37 @@ func (i *Input) IsStandardGamepadButtonPressed(id driver.GamepadID, button drive
 	}
 	return g.standardButtonPressed[button]
 }
+
+func (i *Input) VibrateGamepad(id driver.GamepadID, duration time.Duration, strongMagnitude float64, weakMagnitude float64) {
+	g, ok := i.gamepads[id]
+	if !ok {
+		return
+	}
+
+	// vibrationActuator is avaialble on Chrome.
+	if va := g.value.Get("vibrationActuator"); va.Truthy() {
+		if !va.Get("playEffect").Truthy() {
+			return
+		}
+
+		prop := object.New()
+		prop.Set("startDelay", 0)
+		prop.Set("duration", float64(duration/time.Millisecond))
+		prop.Set("strongMagnitude", strongMagnitude)
+		prop.Set("weakMagnitude", weakMagnitude)
+		va.Call("playEffect", "dual-rumble", prop)
+		return
+	}
+
+	// hapticActuators is available on Firefox.
+	if ha := g.value.Get("hapticActuators"); ha.Truthy() {
+		// TODO: Is this order correct?
+		if ha.Length() > 0 {
+			ha.Index(0).Call("pulse", strongMagnitude, float64(duration/time.Millisecond))
+		}
+		if ha.Length() > 1 {
+			ha.Index(1).Call("pulse", weakMagnitude, float64(duration/time.Millisecond))
+		}
+		return
+	}
+}

internal/uidriver/mobile/input.go

@@ -191,6 +191,10 @@ func (i *Input) IsMouseButtonPressed(key driver.MouseButton) bool {
 	return false
 }
 
+func (i *Input) VibrateGamepad(id driver.GamepadID, duration time.Duration, strongMagnitude float64, weakMagnitude float64) {
+	// TODO: Implement this (#1452)
+}
+
 func (i *Input) update(keys map[driver.Key]struct{}, runes []rune, touches []Touch) {
 	i.ui.m.Lock()
 	defer i.ui.m.Unlock()

vibrate.go

@@ -28,8 +28,8 @@ func Vibrate(duration time.Duration) {
 	uiDriver().Vibrate(duration)
 }
 
-// GamepadVibrateOptions represents the options to vibrate a gamepad.
+// VibrateGamepadOptions represents the options to vibrate a gamepad.
-type GamepadVibrateOptions struct {
+type VibrateGamepadOptions struct {
 	// Duration is the time duration of the effect.
 	Duration time.Duration
 
@@ -42,4 +42,9 @@ type GamepadVibrateOptions struct {
 	WeakMagnitude float64
 }
 
-// TODO: Add a function VibrateGamepad.
+// VibrateGamepad vibrates the specified gamepad with the specified options.
+//
+// VibrateGamepad is concurrent-safe.
+func VibrateGamepad(gamepadID GamepadID, options *VibrateGamepadOptions) {
+	uiDriver().Input().VibrateGamepad(gamepadID, options.Duration, options.StrongMagnitude, options.WeakMagnitude)
+}