ebiten: Introduce type GamepadID

Updates #604

examples/blocks/blocks/gamepad.go

@@ -47,7 +47,7 @@ type axis struct {
 }
 
 type gamepadConfig struct {
-	gamepadID            int
+	gamepadID            ebiten.GamepadID
 	gamepadIDInitialized bool
 
 	current         virtualGamepadButton
@@ -59,7 +59,7 @@ type gamepadConfig struct {
 	defaultAxesValues map[int]float64
 }
 
-func (c *gamepadConfig) SetGamepadID(id int) {
+func (c *gamepadConfig) SetGamepadID(id ebiten.GamepadID) {
 	c.gamepadID = id
 	c.gamepadIDInitialized = true
 }

examples/blocks/blocks/gamepadscene.go

@@ -24,7 +24,7 @@ import (
 )
 
 type GamepadScene struct {
-	gamepadID         int
+	gamepadID         ebiten.GamepadID
 	currentIndex      int
 	countAfterSetting int
 	buttonStates      []string

examples/blocks/blocks/input.go

@@ -27,7 +27,7 @@ type Input struct {
 
 // GamepadIDButtonPressed returns a gamepad ID where at least one button is pressed.
 // If no button is pressed, GamepadIDButtonPressed returns -1.
-func (i *Input) GamepadIDButtonPressed() int {
+func (i *Input) GamepadIDButtonPressed() ebiten.GamepadID {
 	for _, id := range ebiten.GamepadIDs() {
 		for b := ebiten.GamepadButton(0); b <= ebiten.GamepadButtonMax; b++ {
 			if ebiten.IsGamepadButtonPressed(id, b) {

examples/gamepad/main.go

@@ -34,14 +34,14 @@ const (
 )
 
 type Game struct {
-	gamepadIDs     map[int]struct{}
+	gamepadIDs     map[ebiten.GamepadID]struct{}
-	axes           map[int][]string
+	axes           map[ebiten.GamepadID][]string
-	pressedButtons map[int][]string
+	pressedButtons map[ebiten.GamepadID][]string
 }
 
 func (g *Game) Update() error {
 	if g.gamepadIDs == nil {
-		g.gamepadIDs = map[int]struct{}{}
+		g.gamepadIDs = map[ebiten.GamepadID]struct{}{}
 	}
 
 	// Log the gamepad connection events.
@@ -56,8 +56,8 @@ func (g *Game) Update() error {
 		}
 	}
 
-	g.axes = map[int][]string{}
+	g.axes = map[ebiten.GamepadID][]string{}
-	g.pressedButtons = map[int][]string{}
+	g.pressedButtons = map[ebiten.GamepadID][]string{}
 	for id := range g.gamepadIDs {
 		maxAxis := ebiten.GamepadAxisNum(id)
 		for a := 0; a < maxAxis; a++ {
@@ -86,11 +86,13 @@ func (g *Game) Draw(screen *ebiten.Image) {
 	// Draw the current gamepad status.
 	str := ""
 	if len(g.gamepadIDs) > 0 {
-		ids := make([]int, 0, len(g.gamepadIDs))
+		ids := make([]ebiten.GamepadID, 0, len(g.gamepadIDs))
 		for id := range g.gamepadIDs {
 			ids = append(ids, id)
 		}
-		sort.Ints(ids)
+		sort.Slice(ids, func(a, b int) bool {
+			return ids[a] < ids[b]
+		})
 		for _, id := range ids {
 			str += fmt.Sprintf("Gamepad (ID: %d, SDL ID: %s):\n", id, ebiten.GamepadSDLID(id))
 			str += fmt.Sprintf("  Axes:    %s\n", strings.Join(g.axes[id], ", "))

input.go

@@ -103,18 +103,21 @@ func IsMouseButtonPressed(mouseButton MouseButton) bool {
 	return uiDriver().Input().IsMouseButtonPressed(driver.MouseButton(mouseButton))
 }
 
+// GamepadID represents a gamepad's identifier.
+type GamepadID = driver.GamepadID
+
 // GamepadSDLID returns a string with the GUID generated in the same way as SDL.
 // To detect devices, see also the community project of gamepad devices database: https://github.com/gabomdq/SDL_GameControllerDB
 //
 // GamepadSDLID always returns an empty string on browsers and mobiles.
 //
 // GamepadSDLID is concurrent-safe.
-func GamepadSDLID(id int) string {
+func GamepadSDLID(id GamepadID) string {
 	return uiDriver().Input().GamepadSDLID(id)
 }
 
 // GamepadName returns a string with the name.
-// This function may vary in how it returns descriptions for the same device across platforms
+// This function may vary in how it returns descriptions for the same device across platforms.
 // for example the following drivers/platforms see a Xbox One controller as the following:
 //
 //   - Windows: "Xbox Controller"
@@ -124,7 +127,7 @@ func GamepadSDLID(id int) string {
 // GamepadName always returns an empty string on mobiles.
 //
 // GamepadName is concurrent-safe.
-func GamepadName(id int) string {
+func GamepadName(id GamepadID) string {
 	return uiDriver().Input().GamepadName(id)
 }
 
@@ -133,7 +136,7 @@ func GamepadName(id int) string {
 // GamepadIDs is concurrent-safe.
 //
 // GamepadIDs always returns an empty slice on mobiles.
-func GamepadIDs() []int {
+func GamepadIDs() []GamepadID {
 	return uiDriver().Input().GamepadIDs()
 }
 
@@ -142,7 +145,7 @@ func GamepadIDs() []int {
 // GamepadAxisNum is concurrent-safe.
 //
 // GamepadAxisNum always returns 0 on mobiles.
-func GamepadAxisNum(id int) int {
+func GamepadAxisNum(id GamepadID) int {
 	return uiDriver().Input().GamepadAxisNum(id)
 }
 
@@ -151,7 +154,7 @@ func GamepadAxisNum(id int) int {
 // GamepadAxis is concurrent-safe.
 //
 // GamepadAxis always returns 0 on mobiles.
-func GamepadAxis(id int, axis int) float64 {
+func GamepadAxis(id GamepadID, axis int) float64 {
 	return uiDriver().Input().GamepadAxis(id, axis)
 }
 
@@ -160,7 +163,7 @@ func GamepadAxis(id int, axis int) float64 {
 // GamepadButtonNum is concurrent-safe.
 //
 // GamepadButtonNum always returns 0 on mobiles.
-func GamepadButtonNum(id int) int {
+func GamepadButtonNum(id GamepadID) int {
 	return uiDriver().Input().GamepadButtonNum(id)
 }
 
@@ -175,7 +178,7 @@ func GamepadButtonNum(id int) int {
 // There can be differences even between Chrome and Firefox.
 //
 // IsGamepadButtonPressed always returns false on mobiles.
-func IsGamepadButtonPressed(id int, button GamepadButton) bool {
+func IsGamepadButtonPressed(id GamepadID, button GamepadButton) bool {
 	return uiDriver().Input().IsGamepadButtonPressed(id, driver.GamepadButton(button))
 }
 

inpututil/inpututil.go

@@ -30,11 +30,11 @@ type inputState struct {
 	mouseButtonDurations     map[ebiten.MouseButton]int
 	prevMouseButtonDurations map[ebiten.MouseButton]int
 
-	gamepadIDs     map[int]struct{}
+	gamepadIDs     map[ebiten.GamepadID]struct{}
-	prevGamepadIDs map[int]struct{}
+	prevGamepadIDs map[ebiten.GamepadID]struct{}
 
-	gamepadButtonDurations     map[int][]int
+	gamepadButtonDurations     map[ebiten.GamepadID][]int
-	prevGamepadButtonDurations map[int][]int
+	prevGamepadButtonDurations map[ebiten.GamepadID][]int
 
 	touchDurations     map[int]int
 	prevTouchDurations map[int]int
@@ -49,11 +49,11 @@ var theInputState = &inputState{
 	mouseButtonDurations:     map[ebiten.MouseButton]int{},
 	prevMouseButtonDurations: map[ebiten.MouseButton]int{},
 
-	gamepadIDs:     map[int]struct{}{},
+	gamepadIDs:     map[ebiten.GamepadID]struct{}{},
-	prevGamepadIDs: map[int]struct{}{},
+	prevGamepadIDs: map[ebiten.GamepadID]struct{}{},
 
-	gamepadButtonDurations:     map[int][]int{},
+	gamepadButtonDurations:     map[ebiten.GamepadID][]int{},
-	prevGamepadButtonDurations: map[int][]int{},
+	prevGamepadButtonDurations: map[ebiten.GamepadID][]int{},
 
 	touchDurations:     map[int]int{},
 	prevTouchDurations: map[int]int{},
@@ -97,18 +97,18 @@ func (i *inputState) update() {
 	// Gamepads
 
 	// Copy the gamepad IDs.
-	i.prevGamepadIDs = map[int]struct{}{}
+	i.prevGamepadIDs = map[ebiten.GamepadID]struct{}{}
 	for id := range i.gamepadIDs {
 		i.prevGamepadIDs[id] = struct{}{}
 	}
 
 	// Copy the gamepad button durations.
-	i.prevGamepadButtonDurations = map[int][]int{}
+	i.prevGamepadButtonDurations = map[ebiten.GamepadID][]int{}
 	for id, ds := range i.gamepadButtonDurations {
 		i.prevGamepadButtonDurations[id] = append([]int{}, ds...)
 	}
 
-	i.gamepadIDs = map[int]struct{}{}
+	i.gamepadIDs = map[ebiten.GamepadID]struct{}{}
 	for _, id := range ebiten.GamepadIDs() {
 		i.gamepadIDs[id] = struct{}{}
 		if _, ok := i.gamepadButtonDurations[id]; !ok {
@@ -123,13 +123,13 @@ func (i *inputState) update() {
 			}
 		}
 	}
-	idsToDelete := []int{}
+	gamepadIDsToDelete := []ebiten.GamepadID{}
 	for id := range i.gamepadButtonDurations {
 		if _, ok := i.gamepadIDs[id]; !ok {
-			idsToDelete = append(idsToDelete, id)
+			gamepadIDsToDelete = append(gamepadIDsToDelete, id)
 		}
 	}
-	for _, id := range idsToDelete {
+	for _, id := range gamepadIDsToDelete {
 		delete(i.gamepadButtonDurations, id)
 	}
 
@@ -146,13 +146,13 @@ func (i *inputState) update() {
 		ids[id] = struct{}{}
 		i.touchDurations[id]++
 	}
-	idsToDelete = []int{}
+	touchIDsToDelete := []int{}
 	for id := range i.touchDurations {
 		if _, ok := ids[id]; !ok {
-			idsToDelete = append(idsToDelete, id)
+			touchIDsToDelete = append(touchIDsToDelete, id)
 		}
 	}
-	for _, id := range idsToDelete {
+	for _, id := range touchIDsToDelete {
 		delete(i.touchDurations, id)
 	}
 }
@@ -221,8 +221,8 @@ func MouseButtonPressDuration(button ebiten.MouseButton) int {
 // JustConnectedGamepadIDs might return nil when there is no connected gamepad.
 //
 // JustConnectedGamepadIDs is concurrent safe.
-func JustConnectedGamepadIDs() []int {
+func JustConnectedGamepadIDs() []ebiten.GamepadID {
-	var ids []int
+	var ids []ebiten.GamepadID
 	theInputState.m.RLock()
 	for id := range theInputState.gamepadIDs {
 		if _, ok := theInputState.prevGamepadIDs[id]; !ok {
@@ -230,7 +230,9 @@ func JustConnectedGamepadIDs() []int {
 		}
 	}
 	theInputState.m.RUnlock()
-	sort.Ints(ids)
+	sort.Slice(ids, func(a, b int) bool {
+		return ids[a] < ids[b]
+	})
 	return ids
 }
 
@@ -238,7 +240,7 @@ func JustConnectedGamepadIDs() []int {
 // whether the gamepad of the given id is released just in the current frame.
 //
 // IsGamepadJustDisconnected is concurrent safe.
-func IsGamepadJustDisconnected(id int) bool {
+func IsGamepadJustDisconnected(id ebiten.GamepadID) bool {
 	theInputState.m.RLock()
 	_, prev := theInputState.prevGamepadIDs[id]
 	_, current := theInputState.gamepadIDs[id]
@@ -250,7 +252,7 @@ func IsGamepadJustDisconnected(id int) bool {
 // whether the given gamepad button of the gamepad id is pressed just in the current frame.
 //
 // IsGamepadButtonJustPressed is concurrent safe.
-func IsGamepadButtonJustPressed(id int, button ebiten.GamepadButton) bool {
+func IsGamepadButtonJustPressed(id ebiten.GamepadID, button ebiten.GamepadButton) bool {
 	return GamepadButtonPressDuration(id, button) == 1
 }
 
@@ -258,7 +260,7 @@ func IsGamepadButtonJustPressed(id int, button ebiten.GamepadButton) bool {
 // whether the given gamepad button of the gamepad id is released just in the current frame.
 //
 // IsGamepadButtonJustReleased is concurrent safe.
-func IsGamepadButtonJustReleased(id int, button ebiten.GamepadButton) bool {
+func IsGamepadButtonJustReleased(id ebiten.GamepadID, button ebiten.GamepadButton) bool {
 	theInputState.m.RLock()
 	prev := 0
 	if _, ok := theInputState.prevGamepadButtonDurations[id]; ok {
@@ -275,7 +277,7 @@ func IsGamepadButtonJustReleased(id int, button ebiten.GamepadButton) bool {
 // GamepadButtonPressDuration returns how long the gamepad button of the gamepad id is pressed in frames.
 //
 // GamepadButtonPressDuration is concurrent safe.
-func GamepadButtonPressDuration(id int, button ebiten.GamepadButton) int {
+func GamepadButtonPressDuration(id ebiten.GamepadID, button ebiten.GamepadButton) int {
 	theInputState.m.RLock()
 	s := 0
 	if _, ok := theInputState.gamepadButtonDurations[id]; ok {

internal/driver/input.go

@@ -14,15 +14,17 @@
 
 package driver
 
+type GamepadID int
+
 type Input interface {
 	CursorPosition() (x, y int)
-	GamepadSDLID(id int) string
+	GamepadSDLID(id GamepadID) string
-	GamepadName(id int) string
+	GamepadName(id GamepadID) string
-	GamepadAxis(id int, axis int) float64
+	GamepadAxis(id GamepadID, axis int) float64
-	GamepadAxisNum(id int) int
+	GamepadAxisNum(id GamepadID) int
-	GamepadButtonNum(id int) int
+	GamepadButtonNum(id GamepadID) int
-	GamepadIDs() []int
+	GamepadIDs() []GamepadID
-	IsGamepadButtonPressed(id int, button GamepadButton) bool
+	IsGamepadButtonPressed(id GamepadID, button GamepadButton) bool
 	IsKeyPressed(key Key) bool
 	IsMouseButtonPressed(button MouseButton) bool
 	RuneBuffer() []rune

internal/uidriver/glfw/input.go

@@ -67,15 +67,15 @@ func (i *Input) CursorPosition() (x, y int) {
 	return cx, cy
 }
 
-func (i *Input) GamepadIDs() []int {
+func (i *Input) GamepadIDs() []driver.GamepadID {
 	if !i.ui.isRunning() {
 		return nil
 	}
-	var r []int
+	var r []driver.GamepadID
 	_ = i.ui.t.Call(func() error {
 		for id, g := range i.gamepads {
 			if g.valid {
-				r = append(r, id)
+				r = append(r, driver.GamepadID(id))
 			}
 		}
 		return nil
@@ -83,13 +83,13 @@ func (i *Input) GamepadIDs() []int {
 	return r
 }
 
-func (i *Input) GamepadSDLID(id int) string {
+func (i *Input) GamepadSDLID(id driver.GamepadID) string {
 	if !i.ui.isRunning() {
 		return ""
 	}
 	var r string
 	_ = i.ui.t.Call(func() error {
-		if len(i.gamepads) <= id {
+		if len(i.gamepads) <= int(id) {
 			return nil
 		}
 		r = i.gamepads[id].guid
@@ -98,13 +98,13 @@ func (i *Input) GamepadSDLID(id int) string {
 	return r
 }
 
-func (i *Input) GamepadName(id int) string {
+func (i *Input) GamepadName(id driver.GamepadID) string {
 	if !i.ui.isRunning() {
 		return ""
 	}
 	var r string
 	_ = i.ui.t.Call(func() error {
-		if len(i.gamepads) <= id {
+		if len(i.gamepads) <= int(id) {
 			return nil
 		}
 		r = i.gamepads[id].name
@@ -113,13 +113,13 @@ func (i *Input) GamepadName(id int) string {
 	return r
 }
 
-func (i *Input) GamepadAxisNum(id int) int {
+func (i *Input) GamepadAxisNum(id driver.GamepadID) int {
 	if !i.ui.isRunning() {
 		return 0
 	}
 	var r int
 	_ = i.ui.t.Call(func() error {
-		if len(i.gamepads) <= id {
+		if len(i.gamepads) <= int(id) {
 			return nil
 		}
 		r = i.gamepads[id].axisNum
@@ -128,13 +128,13 @@ func (i *Input) GamepadAxisNum(id int) int {
 	return r
 }
 
-func (i *Input) GamepadAxis(id int, axis int) float64 {
+func (i *Input) GamepadAxis(id driver.GamepadID, axis int) float64 {
 	if !i.ui.isRunning() {
 		return 0
 	}
 	var r float64
 	_ = i.ui.t.Call(func() error {
-		if len(i.gamepads) <= id {
+		if len(i.gamepads) <= int(id) {
 			return nil
 		}
 		r = i.gamepads[id].axes[axis]
@@ -143,13 +143,13 @@ func (i *Input) GamepadAxis(id int, axis int) float64 {
 	return r
 }
 
-func (i *Input) GamepadButtonNum(id int) int {
+func (i *Input) GamepadButtonNum(id driver.GamepadID) int {
 	if !i.ui.isRunning() {
 		return 0
 	}
 	var r int
 	_ = i.ui.t.Call(func() error {
-		if len(i.gamepads) <= id {
+		if len(i.gamepads) <= int(id) {
 			return nil
 		}
 		r = i.gamepads[id].buttonNum
@@ -158,13 +158,13 @@ func (i *Input) GamepadButtonNum(id int) int {
 	return r
 }
 
-func (i *Input) IsGamepadButtonPressed(id int, button driver.GamepadButton) bool {
+func (i *Input) IsGamepadButtonPressed(id driver.GamepadID, button driver.GamepadButton) bool {
 	if !i.ui.isRunning() {
 		return false
 	}
 	var r bool
 	_ = i.ui.t.Call(func() error {
-		if len(i.gamepads) <= id {
+		if len(i.gamepads) <= int(id) {
 			return nil
 		}
 		r = i.gamepads[id].buttonPressed[button]

internal/uidriver/js/input_js.go

@@ -56,10 +56,10 @@ func (i *Input) CursorPosition() (x, y int) {
 	return int(xf), int(yf)
 }
 
-func (i *Input) GamepadSDLID(id int) string {
+func (i *Input) GamepadSDLID(id driver.GamepadID) string {
 	// This emulates the implementation of EMSCRIPTEN_JoystickGetDeviceGUID.
 	// https://hg.libsdl.org/SDL/file/bc90ce38f1e2/src/joystick/emscripten/SDL_sysjoystick.c#l385
-	if len(i.gamepads) <= id {
+	if len(i.gamepads) <= int(id) {
 		return ""
 	}
 	var sdlid [16]byte
@@ -70,49 +70,49 @@ func (i *Input) GamepadSDLID(id int) string {
 // GamepadName returns a string containing some information about the controller.
 // A PS2 controller returned "810-3-USB Gamepad" on Firefox
 // A Xbox 360 controller returned "xinput" on Firefox and "Xbox 360 Controller (XInput STANDARD GAMEPAD)" on Chrome
-func (i *Input) GamepadName(id int) string {
+func (i *Input) GamepadName(id driver.GamepadID) string {
-	if len(i.gamepads) <= id {
+	if len(i.gamepads) <= int(id) {
 		return ""
 	}
 	return i.gamepads[id].name
 }
 
-func (i *Input) GamepadIDs() []int {
+func (i *Input) GamepadIDs() []driver.GamepadID {
 	if len(i.gamepads) == 0 {
 		return nil
 	}
-	r := []int{}
+	var r []driver.GamepadID
 	for id, g := range i.gamepads {
 		if g.valid {
-			r = append(r, id)
+			r = append(r, driver.GamepadID(id))
 		}
 	}
 	return r
 }
 
-func (i *Input) GamepadAxisNum(id int) int {
+func (i *Input) GamepadAxisNum(id driver.GamepadID) int {
-	if len(i.gamepads) <= id {
+	if len(i.gamepads) <= int(id) {
 		return 0
 	}
 	return i.gamepads[id].axisNum
 }
 
-func (i *Input) GamepadAxis(id int, axis int) float64 {
+func (i *Input) GamepadAxis(id driver.GamepadID, axis int) float64 {
-	if len(i.gamepads) <= id {
+	if len(i.gamepads) <= int(id) {
 		return 0
 	}
 	return i.gamepads[id].axes[axis]
 }
 
-func (i *Input) GamepadButtonNum(id int) int {
+func (i *Input) GamepadButtonNum(id driver.GamepadID) int {
-	if len(i.gamepads) <= id {
+	if len(i.gamepads) <= int(id) {
 		return 0
 	}
 	return i.gamepads[id].buttonNum
 }
 
-func (i *Input) IsGamepadButtonPressed(id int, button driver.GamepadButton) bool {
+func (i *Input) IsGamepadButtonPressed(id driver.GamepadID, button driver.GamepadButton) bool {
-	if len(i.gamepads) <= id {
+	if len(i.gamepads) <= int(id) {
 		return false
 	}
 	return i.gamepads[id].buttonPressed[button]

internal/uidriver/mobile/input.go

@@ -41,18 +41,18 @@ func (i *Input) CursorPosition() (x, y int) {
 	return i.ui.adjustPosition(i.cursorX, i.cursorY)
 }
 
-func (i *Input) GamepadIDs() []int {
+func (i *Input) GamepadIDs() []driver.GamepadID {
 	i.ui.m.RLock()
 	defer i.ui.m.RUnlock()
 
-	ids := make([]int, 0, len(i.gamepads))
+	ids := make([]driver.GamepadID, 0, len(i.gamepads))
 	for _, g := range i.gamepads {
 		ids = append(ids, g.ID)
 	}
 	return ids
 }
 
-func (i *Input) GamepadSDLID(id int) string {
+func (i *Input) GamepadSDLID(id driver.GamepadID) string {
 	i.ui.m.RLock()
 	defer i.ui.m.RUnlock()
 
@@ -65,7 +65,7 @@ func (i *Input) GamepadSDLID(id int) string {
 	return ""
 }
 
-func (i *Input) GamepadName(id int) string {
+func (i *Input) GamepadName(id driver.GamepadID) string {
 	i.ui.m.RLock()
 	defer i.ui.m.RUnlock()
 
@@ -78,7 +78,7 @@ func (i *Input) GamepadName(id int) string {
 	return ""
 }
 
-func (i *Input) GamepadAxisNum(id int) int {
+func (i *Input) GamepadAxisNum(id driver.GamepadID) int {
 	i.ui.m.RLock()
 	defer i.ui.m.RUnlock()
 
@@ -91,7 +91,7 @@ func (i *Input) GamepadAxisNum(id int) int {
 	return 0
 }
 
-func (i *Input) GamepadAxis(id int, axis int) float64 {
+func (i *Input) GamepadAxis(id driver.GamepadID, axis int) float64 {
 	i.ui.m.RLock()
 	defer i.ui.m.RUnlock()
 
@@ -107,7 +107,7 @@ func (i *Input) GamepadAxis(id int, axis int) float64 {
 	return 0
 }
 
-func (i *Input) GamepadButtonNum(id int) int {
+func (i *Input) GamepadButtonNum(id driver.GamepadID) int {
 	i.ui.m.RLock()
 	defer i.ui.m.RUnlock()
 
@@ -120,7 +120,7 @@ func (i *Input) GamepadButtonNum(id int) int {
 	return 0
 }
 
-func (i *Input) IsGamepadButtonPressed(id int, button driver.GamepadButton) bool {
+func (i *Input) IsGamepadButtonPressed(id driver.GamepadID, button driver.GamepadButton) bool {
 	i.ui.m.RLock()
 	defer i.ui.m.RUnlock()
 

internal/uidriver/mobile/ui.go

@@ -480,7 +480,7 @@ type Touch struct {
 }
 
 type Gamepad struct {
-	ID        int
+	ID        driver.GamepadID
 	SDLID     string
 	Name      string
 	Buttons   [driver.GamepadButtonNum]bool

mobile/ebitenmobileview/input.go

@@ -30,7 +30,7 @@ var (
 	keys     = map[driver.Key]struct{}{}
 	runes    []rune
 	touches  = map[int]position{}
-	gamepads = map[int]*mobile.Gamepad{}
+	gamepads = map[driver.GamepadID]*mobile.Gamepad{}
 )
 
 func updateInput() {

mobile/ebitenmobileview/input_android.go

@@ -177,18 +177,18 @@ var androidAxisIDToAxisID = map[int]int{
 var (
 	// deviceIDToGamepadID is a map from Android device IDs to Ebiten gamepad IDs.
 	// As convention, Ebiten gamepad IDs start with 0, and many applications depend on this fact.
-	deviceIDToGamepadID = map[int]int{}
+	deviceIDToGamepadID = map[int]driver.GamepadID{}
 )
 
-func gamepadIDFromDeviceID(deviceID int) int {
+func gamepadIDFromDeviceID(deviceID int) driver.GamepadID {
 	if id, ok := deviceIDToGamepadID[deviceID]; ok {
 		return id
 	}
-	ids := map[int]struct{}{}
+	ids := map[driver.GamepadID]struct{}{}
 	for _, id := range deviceIDToGamepadID {
 		ids[id] = struct{}{}
 	}
-	for i := 0; ; i++ {
+	for i := driver.GamepadID(0); ; i++ {
 		if _, ok := ids[i]; ok {
 			continue
 		}