Add package inpututil (#415)

inpututil/inpututil.go

@@ -0,0 +1,160 @@
+// Copyright 2018 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 inpututil provides utility functions of input like keyboard or mouse.
+//
+// Note: This package is experimental and API might be changed.
+package inpututil
+
+import (
+	"github.com/hajimehoshi/ebiten"
+	"github.com/hajimehoshi/ebiten/internal/hooks"
+	"github.com/hajimehoshi/ebiten/internal/sync"
+)
+
+type inputState struct {
+	keyStates           map[ebiten.Key]int
+	mouseButtonStates   map[ebiten.MouseButton]int
+	gamepadButtonStates map[int]map[ebiten.GamepadButton]int
+	touchStates         map[int]int
+
+	m sync.RWMutex
+}
+
+var theInputState = &inputState{
+	keyStates:           map[ebiten.Key]int{},
+	mouseButtonStates:   map[ebiten.MouseButton]int{},
+	gamepadButtonStates: map[int]map[ebiten.GamepadButton]int{},
+	touchStates:         map[int]int{},
+}
+
+func init() {
+	hooks.AppendHookOnUpdate(func() error {
+		theInputState.update()
+		return nil
+	})
+}
+
+func (i *inputState) update() {
+	i.m.Lock()
+	defer i.m.Unlock()
+
+	for k := ebiten.Key(0); k < ebiten.KeyMax; k++ {
+		if ebiten.IsKeyPressed(k) {
+			i.keyStates[k]++
+		} else {
+			i.keyStates[k] = 0
+		}
+	}
+
+	for _, b := range []ebiten.MouseButton{
+		ebiten.MouseButtonLeft,
+		ebiten.MouseButtonRight,
+		ebiten.MouseButtonMiddle,
+	} {
+		if ebiten.IsMouseButtonPressed(b) {
+			i.mouseButtonStates[b]++
+		} else {
+			i.mouseButtonStates[b] = 0
+		}
+	}
+
+	for _, id := range ebiten.GamepadIDs() {
+		if _, ok := i.gamepadButtonStates[id]; !ok {
+			i.gamepadButtonStates[id] = map[ebiten.GamepadButton]int{}
+		}
+		n := ebiten.GamepadButtonNum(id)
+		for b := ebiten.GamepadButton(0); b < ebiten.GamepadButton(n); b++ {
+			if ebiten.IsGamepadButtonPressed(id, b) {
+				i.gamepadButtonStates[id][b]++
+			} else {
+				i.gamepadButtonStates[id][b] = 0
+			}
+		}
+	}
+
+	ids := map[int]struct{}{}
+	for _, t := range ebiten.Touches() {
+		ids[t.ID()] = struct{}{}
+		i.touchStates[t.ID()]++
+	}
+	idsToDelete := []int{}
+	for id := range i.touchStates {
+		if _, ok := ids[id]; !ok {
+			idsToDelete = append(idsToDelete, id)
+		}
+	}
+	for _, id := range idsToDelete {
+		delete(i.touchStates, id)
+	}
+}
+
+// IsKeyJustPressed returns a boolean value indicating
+// whether the given key is pressed just in the current frame.
+func IsKeyJustPressed(key ebiten.Key) bool {
+	return KeyPressDuration(key) == 1
+}
+
+// KeyPressDuration returns how long the key is pressed in frames.
+func KeyPressDuration(key ebiten.Key) int {
+	theInputState.m.RLock()
+	s := theInputState.keyStates[key]
+	theInputState.m.RUnlock()
+	return s
+}
+
+// IsMouseButtonJustPressed returns a boolean value indicating
+// whether the given mouse button is pressed just in the current frame.
+func IsMouseButtonJustPressed(button ebiten.MouseButton) bool {
+	return MouseButtonPressDuration(button) == 1
+}
+
+// MouseButtonPressDuration returns how long the mouse button is pressed in frames.
+func MouseButtonPressDuration(button ebiten.MouseButton) int {
+	theInputState.m.RLock()
+	s := theInputState.mouseButtonStates[button]
+	theInputState.m.RUnlock()
+	return s
+}
+
+// IsGamepadButtonJustPressed returns a boolean value indicating
+// whether the given gamepad button of the gamepad id is pressed just in the current frame.
+func IsGamepadButtonJustPressed(id int, button ebiten.GamepadButton) bool {
+	return GamepadButtonPressDuration(id, button) == 1
+}
+
+// GamepadButtonPressDuration returns how long the gamepad button of the gamepad id is pressed in frames.
+func GamepadButtonPressDuration(id int, button ebiten.GamepadButton) int {
+	theInputState.m.RLock()
+	s := 0
+	if _, ok := theInputState.gamepadButtonStates[id]; ok {
+		s = theInputState.gamepadButtonStates[id][button]
+	}
+	theInputState.m.RUnlock()
+	return s
+}
+
+// IsJustTouched returns a boolean value indicating
+// whether the given touch is pressed just in the current frame.
+func IsJustTouched(id int) bool {
+	return TouchDuration(id) == 1
+}
+
+// TouchDuration returns how long the touch remains in frames.
+func TouchDuration(id int) int {
+	theInputState.m.RLock()
+	s := theInputState.touchStates[id]
+	theInputState.m.RUnlock()
+	return s
+}