From e4ca01db31ce07602e0df0f4d43f18ff9fba9873 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 28 May 2016 23:15:28 +0900
Subject: [PATCH] mobile: Multitouches (#101)

---
 examples/mobile/mobile/update.go |  6 ++--
 internal/ui/input_mobile.go      | 24 +++++---------
 internal/ui/ui_mobile.go         | 15 ++-------
 mobile/run.go                    | 55 ++++++++++++++++++++++++++------
 4 files changed, 58 insertions(+), 42 deletions(-)

diff --git a/examples/mobile/mobile/update.go b/examples/mobile/mobile/update.go
index 71d28d5a1..688ba7c5c 100644
--- a/examples/mobile/mobile/update.go
+++ b/examples/mobile/mobile/update.go
@@ -131,9 +131,9 @@ func Update(screen *ebiten.Image) error {
 		return err
 	}
 	msg := ""
-	if ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
-		x, y := ebiten.CursorPosition()
-		msg = fmt.Sprintf("(%d, %d)", x, y)
+	for _, t := range ebiten.Touches() {
+		x, y := t.Position()
+		msg += fmt.Sprintf("ID: %d, (%d, %d)\n", t.ID(), x, y)
 	}
 	ebitenutil.DebugPrint(screen, msg)
 	return nil
diff --git a/internal/ui/input_mobile.go b/internal/ui/input_mobile.go
index dde327561..fc7799951 100644
--- a/internal/ui/input_mobile.go
+++ b/internal/ui/input_mobile.go
@@ -16,22 +16,14 @@
 
 package ui
 
-func (i *input) touchDown(x, y int) {
+func (i *input) updateTouches(touches []Touch) {
 	i.m.Lock()
 	defer i.m.Unlock()
-	i.mouseButtonPressed[MouseButtonLeft] = true
-	i.cursorX, i.cursorY = x, y
-}
-
-func (i *input) touchUp(x, y int) {
-	i.m.Lock()
-	defer i.m.Unlock()
-	i.mouseButtonPressed[MouseButtonLeft] = false
-	i.cursorX, i.cursorY = x, y
-}
-
-func (i *input) touchMove(x, y int) {
-	i.m.Lock()
-	defer i.m.Unlock()
-	i.cursorX, i.cursorY = x, y
+	ts := make([]touch, len(touches))
+	for i := 0; i < len(ts); i++ {
+		ts[i].id = touches[i].ID()
+		x, y := touches[i].Position()
+		ts[i].x, ts[i].y = x, y
+	}
+	i.touches = ts
 }
diff --git a/internal/ui/ui_mobile.go b/internal/ui/ui_mobile.go
index 35ed487dc..eeb448f48 100644
--- a/internal/ui/ui_mobile.go
+++ b/internal/ui/ui_mobile.go
@@ -149,17 +149,6 @@ func Resume() {
 	}()
 }
 
-func TouchDown(x, y int) {
-	s := currentUI.actualScreenScale()
-	currentInput.touchDown(x/s, y/s)
-}
-
-func TouchUp(x, y int) {
-	s := currentUI.actualScreenScale()
-	currentInput.touchUp(x/s, y/s)
-}
-
-func TouchMove(x, y int) {
-	s := currentUI.actualScreenScale()
-	currentInput.touchMove(x/s, y/s)
+func UpdateTouches(touches []Touch) {
+	currentInput.updateTouches(touches)
 }
diff --git a/mobile/run.go b/mobile/run.go
index 4f69c66d7..adfc961bd 100644
--- a/mobile/run.go
+++ b/mobile/run.go
@@ -32,9 +32,9 @@ type EventDispatcher interface {
 	Render() error
 	Pause()
 	Resume()
-	TouchDown(x, y int)
-	TouchUp(x, y int)
-	TouchMove(x, y int)
+	TouchDown(id int, x, y int)
+	TouchMove(id int, x, y int)
+	TouchUp(id int)
 }
 
 // Start starts the game and returns immediately.
@@ -42,10 +42,18 @@ type EventDispatcher interface {
 // Different from ebiten.Run, this invokes only the game loop and not the main (UI) loop.
 func Start(f func(*ebiten.Image) error, width, height, scale int, title string) (EventDispatcher, error) {
 	chError = ebiten.RunWithoutMainLoop(f, width, height, scale, title)
-	return &eventDispatcher{}, nil
+	return &eventDispatcher{
+		touches: map[int]position{},
+	}, nil
+}
+
+type position struct {
+	x int
+	y int
 }
 
 type eventDispatcher struct {
+	touches map[int]position
 }
 
 func (e *eventDispatcher) SetScreenSize(width, height int) {
@@ -74,14 +82,41 @@ func (e *eventDispatcher) Resume() {
 	ui.Resume()
 }
 
-func (e *eventDispatcher) TouchDown(x, y int) {
-	ui.TouchDown(x, y)
+// touch implements ui.Touch.
+type touch struct {
+	id       int
+	position position
 }
 
-func (e *eventDispatcher) TouchUp(x, y int) {
-	ui.TouchUp(x, y)
+func (t touch) ID() int {
+	return t.id
 }
 
-func (e *eventDispatcher) TouchMove(x, y int) {
-	ui.TouchMove(x, y)
+func (t touch) Position() (int, int) {
+	// TODO: Is this OK to adjust the position here?
+	return t.position.x / ui.CurrentUI().ScreenScale(),
+		t.position.y / ui.CurrentUI().ScreenScale()
+}
+
+func (e *eventDispatcher) TouchDown(id int, x, y int) {
+	e.touches[id] = position{x, y}
+	e.updateTouches()
+}
+
+func (e *eventDispatcher) TouchMove(id int, x, y int) {
+	e.touches[id] = position{x, y}
+	e.updateTouches()
+}
+
+func (e *eventDispatcher) TouchUp(id int) {
+	delete(e.touches, id)
+	e.updateTouches()
+}
+
+func (e *eventDispatcher) updateTouches() {
+	ts := []ui.Touch{}
+	for id, position := range e.touches {
+		ts = append(ts, touch{id, position})
+	}
+	ui.UpdateTouches(ts)
 }