internal/gamepad: port the implementation for Android

internal/gamepad/extern_android.go

@@ -0,0 +1,167 @@
+// Copyright 2022 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package gamepad
+
+import (
+	"fmt"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/driver"
+)
+
+type AndroidHatDirection int
+
+const (
+	AndroidHatDirectionX AndroidHatDirection = iota
+	AndroidHatDirectionY
+)
+
+func AddAndroidGamepad(androidDeviceID int, name, sdlID string, axisCount, buttonCount, hatCount int) {
+	theGamepads.addAndroidGamepad(androidDeviceID, name, sdlID, axisCount, buttonCount, hatCount)
+}
+
+func RemoveAndroidGamepad(androidDeviceID int) {
+	theGamepads.removeAndroidGamepad(androidDeviceID)
+}
+
+func UpdateAndroidGamepadAxis(androidDeviceID int, axis int, value float64) {
+	theGamepads.updateAndroidGamepadAxis(androidDeviceID, axis, value)
+}
+
+func UpdateAndroidGamepadButton(androidDeviceID int, button driver.GamepadButton, pressed bool) {
+	theGamepads.updateAndroidGamepadButton(androidDeviceID, button, pressed)
+}
+
+func UpdateAndroidGamepadHat(androidDeviceID int, hat int, dir AndroidHatDirection, value int) {
+	theGamepads.updateAndroidGamepadHat(androidDeviceID, hat, dir, value)
+}
+
+func (g *gamepads) addAndroidGamepad(androidDeviceID int, name, sdlID string, axisCount, buttonCount, hatCount int) {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	gp := g.add(name, sdlID)
+	gp.androidDeviceID = androidDeviceID
+	gp.axisCount_ = axisCount
+	gp.buttonCount_ = buttonCount
+	gp.hatCount_ = hatCount
+	gp.axes = make([]float64, axisCount)
+	gp.buttons = make([]bool, buttonCount)
+	gp.hats = make([]int, hatCount)
+}
+
+func (g *gamepads) removeAndroidGamepad(androidDeviceID int) {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	g.remove(func(gamepad *Gamepad) bool {
+		return gamepad.androidDeviceID == androidDeviceID
+	})
+}
+
+func (g *gamepads) updateAndroidGamepadAxis(androidDeviceID int, axis int, value float64) {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	gp := g.find(func(gamepad *Gamepad) bool {
+		return gamepad.androidDeviceID == androidDeviceID
+	})
+	if gp == nil {
+		return
+	}
+	gp.updateAndroidGamepadAxis(axis, value)
+}
+
+func (g *gamepads) updateAndroidGamepadButton(androidDeviceID int, button driver.GamepadButton, pressed bool) {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	gp := g.find(func(gamepad *Gamepad) bool {
+		return gamepad.androidDeviceID == androidDeviceID
+	})
+	if gp == nil {
+		return
+	}
+	gp.updateAndroidGamepadButton(button, pressed)
+}
+
+func (g *gamepads) updateAndroidGamepadHat(androidDeviceID int, hat int, dir AndroidHatDirection, value int) {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	gp := g.find(func(gamepad *Gamepad) bool {
+		return gamepad.androidDeviceID == androidDeviceID
+	})
+	if gp == nil {
+		return
+	}
+	gp.updateAndroidGamepadHat(hat, dir, value)
+}
+
+func (g *Gamepad) updateAndroidGamepadAxis(axis int, value float64) {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	if axis < 0 || axis >= g.axisCount_ {
+		return
+	}
+	g.axes[axis] = value
+}
+
+func (g *Gamepad) updateAndroidGamepadButton(button driver.GamepadButton, pressed bool) {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	if button < 0 || int(button) >= g.buttonCount_ {
+		return
+	}
+	g.buttons[button] = pressed
+}
+
+func (g *Gamepad) updateAndroidGamepadHat(hat int, dir AndroidHatDirection, value int) {
+	g.m.Lock()
+	defer g.m.Unlock()
+
+	if hat < 0 || hat >= g.hatCount_ {
+		return
+	}
+	v := g.hats[hat]
+	switch dir {
+	case AndroidHatDirectionX:
+		switch {
+		case value < 0:
+			v |= hatLeft
+			v &^= hatRight
+		case value > 0:
+			v &^= hatLeft
+			v |= hatRight
+		default:
+			v &^= (hatLeft | hatRight)
+		}
+	case AndroidHatDirectionY:
+		switch {
+		case value < 0:
+			v |= hatUp
+			v &^= hatDown
+		case value > 0:
+			v &^= hatUp
+			v |= hatDown
+		default:
+			v &^= (hatUp | hatDown)
+		}
+	default:
+		panic(fmt.Sprintf("gamepad: invalid direction: %d", dir))
+	}
+	g.hats[hat] = v
+}

internal/gamepad/gamepad_android.go

@@ -0,0 +1,91 @@
+// Copyright 2022 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package gamepad
+
+import (
+	"time"
+)
+
+type nativeGamepads struct{}
+
+func (*nativeGamepads) init(gamepads *gamepads) error {
+	return nil
+}
+
+func (*nativeGamepads) update(gamepads *gamepads) error {
+	return nil
+}
+
+type nativeGamepad struct {
+	androidDeviceID int
+
+	axisCount_   int
+	buttonCount_ int
+	hatCount_    int
+
+	axes    []float64
+	buttons []bool
+	hats    []int
+}
+
+func (*nativeGamepad) update(gamepad *gamepads) error {
+	// Do nothing. The state of gamepads are given via APIs in extern_android.go.
+	return nil
+}
+
+func (*nativeGamepad) hasOwnStandardLayoutMapping() bool {
+	return false
+}
+
+func (g *nativeGamepad) axisCount() int {
+	return g.axisCount_
+}
+
+func (g *nativeGamepad) buttonCount() int {
+	return g.buttonCount_
+}
+
+func (g *nativeGamepad) hatCount() int {
+	return g.hatCount_
+}
+
+func (g *nativeGamepad) axisValue(axis int) float64 {
+	if axis < 0 || axis >= len(g.axes) {
+		return 0
+	}
+	return g.axes[axis]
+}
+
+func (g *nativeGamepad) isButtonPressed(button int) bool {
+	if button < 0 || button >= len(g.buttons) {
+		return false
+	}
+	return g.buttons[button]
+}
+
+func (*nativeGamepad) buttonValue(button int) float64 {
+	panic("gamepad: buttonValue is not implemented")
+}
+
+func (g *nativeGamepad) hatState(hat int) int {
+	if hat < 0 || hat >= len(g.hats) {
+		return 0
+	}
+	return g.hats[hat]
+}
+
+func (g *nativeGamepad) vibrate(duration time.Duration, strongMagnitude float64, weakMagnitude float64) {
+	// TODO: Implement this (#1452)
+}

internal/gamepad/gamepad_null.go

@@ -12,10 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build (!darwin || ios) && !js && (!linux || android) && !windows
+//go:build (!darwin || ios) && !js && !linux && !windows
 // +build !darwin ios
 // +build !js
-// +build !linux android
+// +build !linux
 // +build !windows
 
 package gamepad

internal/uidriver/mobile/gamepad.go

@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build android || ios
-// +build android ios
+//go:build android
+// +build android
 
 package mobile
 
@@ -21,186 +21,104 @@ import (
 	"time"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/driver"
-	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepad"
 )
 
-type Gamepad struct {
-	ID        driver.GamepadID
-	SDLID     string
-	Name      string
-	Buttons   [driver.GamepadButtonNum]bool
-	ButtonNum int
-	Axes      [32]float32
-	AxisNum   int
-	Hats      [16]int
-	HatNum    int
-}
-
-type gamepadState struct {
-	g *Gamepad
-}
-
-func (s gamepadState) Axis(index int) float64 {
-	return float64(s.g.Axes[index])
-}
-
-func (s gamepadState) Button(index int) bool {
-	return s.g.Buttons[index]
-}
-
-func (s gamepadState) Hat(index int) int {
-	return s.g.Hats[index]
-}
-
 func (i *Input) AppendGamepadIDs(gamepadIDs []driver.GamepadID) []driver.GamepadID {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		gamepadIDs = append(gamepadIDs, g.ID)
-	}
-	return gamepadIDs
+	return gamepad.AppendGamepadIDs(gamepadIDs)
 }
 
 func (i *Input) GamepadSDLID(id driver.GamepadID) string {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		return g.SDLID
+	g := gamepad.Get(id)
+	if g == nil {
+		return ""
 	}
-	return ""
+	return g.SDLID()
 }
 
 func (i *Input) GamepadName(id driver.GamepadID) string {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		if name := gamepaddb.Name(g.SDLID); name != "" {
-			return name
-		}
-		return g.Name
+	g := gamepad.Get(id)
+	if g == nil {
+		return ""
 	}
-	return ""
+	return g.Name()
 }
 
 func (i *Input) GamepadAxisNum(id driver.GamepadID) int {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		return g.AxisNum
+	g := gamepad.Get(id)
+	if g == nil {
+		return 0
 	}
-	return 0
+	return g.AxisCount()
 }
 
 func (i *Input) GamepadAxisValue(id driver.GamepadID, axis int) float64 {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		if g.AxisNum <= int(axis) {
-			return 0
-		}
-		return float64(g.Axes[axis])
+	g := gamepad.Get(id)
+	if g == nil {
+		return 0
 	}
-	return 0
+	return g.Axis(axis)
 }
 
 func (i *Input) GamepadButtonNum(id driver.GamepadID) int {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		return g.ButtonNum
+	g := gamepad.Get(id)
+	if g == nil {
+		return 0
 	}
-	return 0
+	return g.ButtonCount()
 }
 
 func (i *Input) IsGamepadButtonPressed(id driver.GamepadID, button driver.GamepadButton) bool {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		if g.ButtonNum <= int(button) {
-			return false
-		}
-		return g.Buttons[button]
+	g := gamepad.Get(id)
+	if g == nil {
+		return false
 	}
-	return false
+	return g.Button(int(button))
 }
 
 func (i *Input) IsStandardGamepadLayoutAvailable(id driver.GamepadID) bool {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		return gamepaddb.HasStandardLayoutMapping(g.SDLID)
+	g := gamepad.Get(id)
+	if g == nil {
+		return false
 	}
-	return false
+	return g.IsStandardLayoutAvailable()
 }
 
 func (i *Input) IsStandardGamepadButtonPressed(id driver.GamepadID, button driver.StandardGamepadButton) bool {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		return gamepaddb.IsButtonPressed(g.SDLID, button, gamepadState{&g})
+	g := gamepad.Get(id)
+	if g == nil {
+		return false
 	}
-	return false
+	return g.IsStandardButtonPressed(button)
 }
 
 func (i *Input) StandardGamepadButtonValue(id driver.GamepadID, button driver.StandardGamepadButton) float64 {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		return gamepaddb.ButtonValue(g.SDLID, button, gamepadState{&g})
+	g := gamepad.Get(id)
+	if g == nil {
+		return 0
 	}
-	return 0
+	return g.StandardButtonValue(button)
 }
 
 func (i *Input) StandardGamepadAxisValue(id driver.GamepadID, axis driver.StandardGamepadAxis) float64 {
-	i.ui.m.RLock()
-	defer i.ui.m.RUnlock()
-
-	for _, g := range i.gamepads {
-		if g.ID != id {
-			continue
-		}
-		return gamepaddb.AxisValue(g.SDLID, axis, gamepadState{&g})
+	g := gamepad.Get(id)
+	if g == nil {
+		return 0
 	}
-	return 0
+	return g.StandardAxisValue(axis)
 }
 
 func (i *Input) VibrateGamepad(id driver.GamepadID, duration time.Duration, strongMagnitude float64, weakMagnitude float64) {
-	// TODO: Implement this (#1452)
+	g := gamepad.Get(id)
+	if g == nil {
+		return
+	}
+	g.Vibrate(duration, strongMagnitude, weakMagnitude)
+}
+
+// TODO: Remove this struct after porting the gamepad part of iOS to internal/gamepad.
+type Gamepad struct{}
+
+// TODO: Remove this function after porting the gamepad part of iOS to internal/gamepad.
+func (i *Input) updateGamepads() {
 }

internal/uidriver/mobile/gamepad_android.go

@@ -1,34 +0,0 @@
-// Copyright 2021 The Ebiten Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package mobile
-
-import (
-	"github.com/hajimehoshi/ebiten/v2/internal/driver"
-)
-
-// UpdateGamepads updates the gamepad states.
-// UpdateGamepads is called when the gamepad states are given from outside like Android.
-func (u *UserInterface) UpdateGamepads(gamepads []Gamepad) {
-	u.input.updateGamepadsFromOutside(gamepads)
-}
-
-func (i *Input) updateGamepadsFromOutside(gamepads []Gamepad) {
-	i.gamepads = i.gamepads[:0]
-	i.gamepads = append(i.gamepads, gamepads...)
-}
-
-func (i *Input) updateGamepads() {
-	// Do nothing.
-}

internal/uidriver/mobile/input.go

@@ -22,11 +22,13 @@ import (
 )
 
 type Input struct {
-	keys     map[driver.Key]struct{}
-	runes    []rune
-	touches  []Touch
+	keys    map[driver.Key]struct{}
+	runes   []rune
+	touches []Touch
+	ui      *UserInterface
+
+	// gamepads is used only on iOS.
 	gamepads []Gamepad
-	ui       *UserInterface
 }
 
 func (i *Input) CursorPosition() (x, y int) {

internal/uidriver/mobile/inputgamepad_ios.go

@@ -0,0 +1,206 @@
+// Copyright 2022 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build ios
+// +build ios
+
+package mobile
+
+import (
+	"time"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/driver"
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepaddb"
+)
+
+type Gamepad struct {
+	ID        driver.GamepadID
+	SDLID     string
+	Name      string
+	Buttons   [driver.GamepadButtonNum]bool
+	ButtonNum int
+	Axes      [32]float32
+	AxisNum   int
+	Hats      [16]int
+	HatNum    int
+}
+
+type gamepadState struct {
+	g *Gamepad
+}
+
+func (s gamepadState) Axis(index int) float64 {
+	return float64(s.g.Axes[index])
+}
+
+func (s gamepadState) Button(index int) bool {
+	return s.g.Buttons[index]
+}
+
+func (s gamepadState) Hat(index int) int {
+	return s.g.Hats[index]
+}
+
+func (i *Input) AppendGamepadIDs(gamepadIDs []driver.GamepadID) []driver.GamepadID {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		gamepadIDs = append(gamepadIDs, g.ID)
+	}
+	return gamepadIDs
+}
+
+func (i *Input) GamepadSDLID(id driver.GamepadID) string {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		return g.SDLID
+	}
+	return ""
+}
+
+func (i *Input) GamepadName(id driver.GamepadID) string {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		if name := gamepaddb.Name(g.SDLID); name != "" {
+			return name
+		}
+		return g.Name
+	}
+	return ""
+}
+
+func (i *Input) GamepadAxisNum(id driver.GamepadID) int {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		return g.AxisNum
+	}
+	return 0
+}
+
+func (i *Input) GamepadAxisValue(id driver.GamepadID, axis int) float64 {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		if g.AxisNum <= int(axis) {
+			return 0
+		}
+		return float64(g.Axes[axis])
+	}
+	return 0
+}
+
+func (i *Input) GamepadButtonNum(id driver.GamepadID) int {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		return g.ButtonNum
+	}
+	return 0
+}
+
+func (i *Input) IsGamepadButtonPressed(id driver.GamepadID, button driver.GamepadButton) bool {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		if g.ButtonNum <= int(button) {
+			return false
+		}
+		return g.Buttons[button]
+	}
+	return false
+}
+
+func (i *Input) IsStandardGamepadLayoutAvailable(id driver.GamepadID) bool {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		return gamepaddb.HasStandardLayoutMapping(g.SDLID)
+	}
+	return false
+}
+
+func (i *Input) IsStandardGamepadButtonPressed(id driver.GamepadID, button driver.StandardGamepadButton) bool {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		return gamepaddb.IsButtonPressed(g.SDLID, button, gamepadState{&g})
+	}
+	return false
+}
+
+func (i *Input) StandardGamepadButtonValue(id driver.GamepadID, button driver.StandardGamepadButton) float64 {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		return gamepaddb.ButtonValue(g.SDLID, button, gamepadState{&g})
+	}
+	return 0
+}
+
+func (i *Input) StandardGamepadAxisValue(id driver.GamepadID, axis driver.StandardGamepadAxis) float64 {
+	i.ui.m.RLock()
+	defer i.ui.m.RUnlock()
+
+	for _, g := range i.gamepads {
+		if g.ID != id {
+			continue
+		}
+		return gamepaddb.AxisValue(g.SDLID, axis, gamepadState{&g})
+	}
+	return 0
+}
+
+func (i *Input) VibrateGamepad(id driver.GamepadID, duration time.Duration, strongMagnitude float64, weakMagnitude float64) {
+	// TODO: Implement this (#1452)
+}

internal/uidriver/mobile/ui.go

@@ -34,6 +34,7 @@ import (
 
 	"github.com/hajimehoshi/ebiten/v2/internal/devicescale"
 	"github.com/hajimehoshi/ebiten/v2/internal/driver"
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepad"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicscommand"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/opengl"
 	"github.com/hajimehoshi/ebiten/v2/internal/hooks"
@@ -83,7 +84,9 @@ func (u *UserInterface) Update() error {
 		return nil
 	}
 
+	// TODO: Remove this call after porting the gamepad part of iOS to internal/gamepad.
 	u.input.updateGamepads()
+	gamepad.Update()
 
 	renderCh <- struct{}{}
 	go func() {

mobile/ebitenmobileview/input_android.go

@@ -21,7 +21,7 @@ import (
 	"unicode"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/driver"
-	"github.com/hajimehoshi/ebiten/v2/internal/uidriver/mobile"
+	"github.com/hajimehoshi/ebiten/v2/internal/gamepad"
 )
 
 // https://developer.android.com/reference/android/view/KeyEvent
@@ -180,30 +180,6 @@ var androidAxisIDToHatID2 = map[int]int{
 	axisHatY: 1,
 }
 
-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]driver.GamepadID{}
-)
-
-func gamepadIDFromDeviceID(deviceID int) driver.GamepadID {
-	if id, ok := deviceIDToGamepadID[deviceID]; ok {
-		return id
-	}
-	ids := map[driver.GamepadID]struct{}{}
-	for _, id := range deviceIDToGamepadID {
-		ids[id] = struct{}{}
-	}
-	for i := driver.GamepadID(0); ; i++ {
-		if _, ok := ids[i]; ok {
-			continue
-		}
-		deviceIDToGamepadID[deviceID] = i
-		return i
-	}
-	panic("ebitenmobileview: a gamepad ID cannot be determined")
-}
-
 func UpdateTouchesOnAndroid(action int, id int, x, y int) {
 	switch action {
 	case 0x00, 0x05, 0x02: // ACTION_DOWN, ACTION_POINTER_DOWN, ACTION_MOVE
@@ -215,27 +191,12 @@ func UpdateTouchesOnAndroid(action int, id int, x, y int) {
 	}
 }
 
-func gamepadFromGamepadID(id driver.GamepadID) *mobile.Gamepad {
-	for i, g := range gamepads {
-		if g.ID == id {
-			return &gamepads[i]
-		}
-	}
-	return nil
-}
-
 func OnKeyDownOnAndroid(keyCode int, unicodeChar int, source int, deviceID int) {
 	switch {
 	case source&sourceGamepad == sourceGamepad:
 		// A gamepad can be detected as a keyboard. Detect the device as a gamepad first.
 		if button, ok := androidKeyToGamepadButton[keyCode]; ok {
-			id := gamepadIDFromDeviceID(deviceID)
-			g := gamepadFromGamepadID(id)
-			if g == nil {
-				return
-			}
-			g.Buttons[button] = true
-			updateGamepads()
+			gamepad.UpdateAndroidGamepadButton(deviceID, button, true)
 		}
 	case source&sourceJoystick == sourceJoystick:
 		// DPAD keys can come here, but they are also treated as an axis at a motion event. Ignore them.
@@ -255,13 +216,7 @@ func OnKeyUpOnAndroid(keyCode int, source int, deviceID int) {
 	case source&sourceGamepad == sourceGamepad:
 		// A gamepad can be detected as a keyboard. Detect the device as a gamepad first.
 		if button, ok := androidKeyToGamepadButton[keyCode]; ok {
-			id := gamepadIDFromDeviceID(deviceID)
-			g := gamepadFromGamepadID(id)
-			if g == nil {
-				return
-			}
-			g.Buttons[button] = false
-			updateGamepads()
+			gamepad.UpdateAndroidGamepadButton(deviceID, button, false)
 		}
 	case source&sourceJoystick == sourceJoystick:
 		// DPAD keys can come here, but they are also treated as an axis at a motion event. Ignore them.
@@ -274,15 +229,8 @@ func OnKeyUpOnAndroid(keyCode int, source int, deviceID int) {
 }
 
 func OnGamepadAxesOrHatsChanged(deviceID int, axisID int, value float32) {
-	id := gamepadIDFromDeviceID(deviceID)
-	g := gamepadFromGamepadID(id)
-	if g == nil {
-		return
-	}
-
-	if aid, ok := androidAxisIDToAxisID[axisID]; ok {
-		g.Axes[aid] = value
-		updateGamepads()
+	if axis, ok := androidAxisIDToAxisID[axisID]; ok {
+		gamepad.UpdateAndroidGamepadAxis(deviceID, axis, float64(value))
 		return
 	}
 
@@ -293,38 +241,20 @@ func OnGamepadAxesOrHatsChanged(deviceID int, axisID int, value float32) {
 			hatDown  = 4
 			hatLeft  = 8
 		)
-		hid := hid2 / 2
-		v := g.Hats[hid]
-		if hid2%2 == 0 {
-			hatX := int(math.Round(float64(value)))
-			if hatX < 0 {
-				v |= hatLeft
-				v &^= hatRight
-			} else if hatX > 0 {
-				v &^= hatLeft
-				v |= hatRight
-			} else {
-				v &^= (hatLeft | hatRight)
-			}
-		} else {
-			hatY := int(math.Round(float64(value)))
-			if hatY < 0 {
-				v |= hatUp
-				v &^= hatDown
-			} else if hatY > 0 {
-				v &^= hatUp
-				v |= hatDown
-			} else {
-				v &^= (hatUp | hatDown)
-			}
+		hatID := hid2 / 2
+		var dir gamepad.AndroidHatDirection
+		switch hid2 % 2 {
+		case 0:
+			dir = gamepad.AndroidHatDirectionX
+		case 1:
+			dir = gamepad.AndroidHatDirectionY
 		}
-		g.Hats[hid] = v
-		updateGamepads()
+		gamepad.UpdateAndroidGamepadHat(deviceID, hatID, dir, int(math.Round(float64(value))))
 		return
 	}
 }
 
-func OnGamepadAdded(deviceID int, name string, buttonNum int, axisNum int, hatNum int, descriptor string, vendorID int, productID int, buttonMask int, axisMask int) {
+func OnGamepadAdded(deviceID int, name string, buttonCount int, axisCount int, hatCount int, descriptor string, vendorID int, productID int, buttonMask int, axisMask int) {
 	// This emulates the implementation of Android_AddJoystick.
 	// https://github.com/libsdl-org/SDL/blob/0e9560aea22818884921e5e5064953257bfe7fa7/src/joystick/android/SDL_sysjoystick.c#L386
 	const SDL_HARDWARE_BUS_BLUETOOTH = 0x05
@@ -350,39 +280,9 @@ func OnGamepadAdded(deviceID int, name string, buttonNum int, axisNum int, hatNu
 	sdlid[14] = byte(axisMask)
 	sdlid[15] = byte(axisMask >> 8)
 
-	id := gamepadIDFromDeviceID(deviceID)
-	gamepads = append(gamepads, mobile.Gamepad{
-		ID:        id,
-		SDLID:     hex.EncodeToString(sdlid[:]),
-		Name:      name,
-		ButtonNum: buttonNum,
-		AxisNum:   axisNum,
-		HatNum:    hatNum,
-	})
-	updateGamepads()
+	gamepad.AddAndroidGamepad(deviceID, name, hex.EncodeToString(sdlid[:]), axisCount, buttonCount, hatCount)
 }
 
 func OnInputDeviceRemoved(deviceID int) {
-	if id, ok := deviceIDToGamepadID[deviceID]; ok {
-		idx := -1
-		for i, g := range gamepads {
-			if g.ID == id {
-				idx = i
-				break
-			}
-		}
-		if idx >= 0 {
-			lastIdx := len(gamepads) - 1
-			gamepads[idx], gamepads[lastIdx] = gamepads[lastIdx], gamepads[idx]
-			gamepads = gamepads[:len(gamepads)-1]
-		}
-		delete(deviceIDToGamepadID, deviceID)
-	}
-	updateGamepads()
-}
-
-var gamepads []mobile.Gamepad
-
-func updateGamepads() {
-	mobile.Get().UpdateGamepads(gamepads)
+	gamepad.RemoveAndroidGamepad(deviceID)
 }