From 3195ae32d83dc52dca5b45231823a4d109d17f7f Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Tue, 24 May 2016 00:00:54 +0900
Subject: [PATCH] mobile: Implement Pause/Resume

---
 examples/mobile/main_mobile.go |  2 +-
 graphicscontext.go             | 23 +++++++++++++++++++++++
 internal/graphics/draw.go      |  1 +
 internal/loop/run.go           | 10 ++++++++++
 internal/ui/event.go           | 12 +++++++++---
 internal/ui/ui_mobile.go       | 30 ++++++++++++++++++++++++------
 mobile/run.go                  | 10 ++++++++++
 7 files changed, 78 insertions(+), 10 deletions(-)

diff --git a/examples/mobile/main_mobile.go b/examples/mobile/main_mobile.go
index acd1d566a..4fe7d6def 100644
--- a/examples/mobile/main_mobile.go
+++ b/examples/mobile/main_mobile.go
@@ -29,7 +29,7 @@ import (
 	"github.com/hajimehoshi/ebiten/mobile"
 )
 
-// EventDispacher must be redeclared and exported so that this is available on the Java/Objective-C side.
+// EventDispacher must be redeclared and exported to be available on the Java/Objective-C side.
 
 type EventDispatcher mobile.EventDispatcher
 
diff --git a/graphicscontext.go b/graphicscontext.go
index 7dbf33718..3553755f7 100644
--- a/graphicscontext.go
+++ b/graphicscontext.go
@@ -87,3 +87,26 @@ func (c *graphicsContext) Update() error {
 	}
 	return nil
 }
+
+func (c *graphicsContext) Pause() error {
+	if err := theImages.evacuatePixels(); err != nil {
+		return err
+	}
+	if err := graphics.Finalize(ui.GLContext()); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (c *graphicsContext) Resume() error {
+	if !c.imageTasksDone {
+		return nil
+	}
+	if err := graphics.Initialize(ui.GLContext()); err != nil {
+		return err
+	}
+	if err := theImages.restorePixels(); err != nil {
+		return err
+	}
+	return nil
+}
diff --git a/internal/graphics/draw.go b/internal/graphics/draw.go
index 983f41f35..8dafe7d7b 100644
--- a/internal/graphics/draw.go
+++ b/internal/graphics/draw.go
@@ -17,6 +17,7 @@ package graphics
 import (
 	"errors"
 	"fmt"
+
 	"github.com/hajimehoshi/ebiten/internal/graphics/opengl"
 )
 
diff --git a/internal/loop/run.go b/internal/loop/run.go
index 7597d52bc..2863ec26a 100644
--- a/internal/loop/run.go
+++ b/internal/loop/run.go
@@ -95,6 +95,8 @@ func (c *runContext) setRunningSlowly(isRunningSlowly bool) {
 type GraphicsContext interface {
 	SetSize(width, height, scale int) error
 	Update() error
+	Pause() error
+	Resume() error
 }
 
 func Run(g GraphicsContext, width, height, scale int, title string, fps int) error {
@@ -160,6 +162,14 @@ func Run(g GraphicsContext, width, height, scale int, title string, fps int) err
 				beforeForFPS = n2
 				frames = 0
 			}
+		case ui.PauseEvent:
+			if err := g.Pause(); err != nil {
+				return err
+			}
+		case ui.ResumeEvent:
+			if err := g.Resume(); err != nil {
+				return err
+			}
 		default:
 			panic("not reach")
 		}
diff --git a/internal/ui/event.go b/internal/ui/event.go
index ffd6a0473..a5417c01f 100644
--- a/internal/ui/event.go
+++ b/internal/ui/event.go
@@ -17,12 +17,18 @@ package ui
 type CloseEvent struct {
 }
 
-type RenderEvent struct {
-}
-
 type ScreenSizeEvent struct {
 	Width       int
 	Height      int
 	Scale       int
 	ActualScale int
 }
+
+type RenderEvent struct {
+}
+
+type PauseEvent struct {
+}
+
+type ResumeEvent struct {
+}
diff --git a/internal/ui/ui_mobile.go b/internal/ui/ui_mobile.go
index b6e90480e..35ed487dc 100644
--- a/internal/ui/ui_mobile.go
+++ b/internal/ui/ui_mobile.go
@@ -56,8 +56,10 @@ type userInterface struct {
 	height      int
 	scale       int
 	sizeChanged bool
-	render      chan struct{}
-	renderEnd   chan struct{}
+	chRender    chan struct{}
+	chRenderEnd chan struct{}
+	chPause     chan struct{}
+	chResume    chan struct{}
 }
 
 var (
@@ -65,8 +67,8 @@ var (
 	chRenderEnd = make(chan struct{})
 	currentUI   = &userInterface{
 		sizeChanged: true,
-		render:      chRender,
-		renderEnd:   chRenderEnd,
+		chRender:    chRender,
+		chRenderEnd: chRenderEnd,
 	}
 )
 
@@ -99,7 +101,11 @@ func (u *userInterface) Update() (interface{}, error) {
 		return e, nil
 	}
 	select {
-	case <-u.render:
+	case <-u.chPause:
+		return PauseEvent{}, nil
+	case <-u.chResume:
+		return ResumeEvent{}, nil
+	case <-u.chRender:
 		return RenderEvent{}, nil
 	}
 }
@@ -109,7 +115,7 @@ func (u *userInterface) SwapBuffers() error {
 }
 
 func (u *userInterface) FinishRendering() error {
-	u.renderEnd <- struct{}{}
+	u.chRenderEnd <- struct{}{}
 	return nil
 }
 
@@ -131,6 +137,18 @@ func (u *userInterface) actualScreenScale() int {
 	return u.scale
 }
 
+func Pause() {
+	go func() {
+		currentUI.chPause <- struct{}{}
+	}()
+}
+
+func Resume() {
+	go func() {
+		currentUI.chResume <- struct{}{}
+	}()
+}
+
 func TouchDown(x, y int) {
 	s := currentUI.actualScreenScale()
 	currentInput.touchDown(x/s, y/s)
diff --git a/mobile/run.go b/mobile/run.go
index 8ece510a9..4f69c66d7 100644
--- a/mobile/run.go
+++ b/mobile/run.go
@@ -30,6 +30,8 @@ type EventDispatcher interface {
 	SetScreenSize(width, height int)
 	SetScreenScale(scale int)
 	Render() error
+	Pause()
+	Resume()
 	TouchDown(x, y int)
 	TouchUp(x, y int)
 	TouchMove(x, y int)
@@ -64,6 +66,14 @@ func (e *eventDispatcher) Render() error {
 	return ui.Render(chError)
 }
 
+func (e *eventDispatcher) Pause() {
+	ui.Pause()
+}
+
+func (e *eventDispatcher) Resume() {
+	ui.Resume()
+}
+
 func (e *eventDispatcher) TouchDown(x, y int) {
 	ui.TouchDown(x, y)
 }