From 93f052de8c10ffa9678eded561443b6df6de9cc6 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sun, 3 Jul 2016 16:18:29 +0900
Subject: [PATCH] graphics: Refactoring

---
 graphicscontext.go   | 18 +++++++++---------
 internal/loop/run.go | 31 +++----------------------------
 run.go               | 16 +++++++++++++++-
 3 files changed, 27 insertions(+), 38 deletions(-)

diff --git a/graphicscontext.go b/graphicscontext.go
index 6593b2c1b..1db531207 100644
--- a/graphicscontext.go
+++ b/graphicscontext.go
@@ -132,18 +132,18 @@ func (c *graphicsContext) drawToDefaultRenderTarget(context *opengl.Context) err
 	return nil
 }
 
-func (c *graphicsContext) UpdateAndDraw() error {
+func (c *graphicsContext) UpdateAndDraw(updateCount int) error {
 	if err := c.initializeIfNeeded(ui.GLContext()); err != nil {
 		return err
 	}
-	if err := c.offscreen.Clear(); err != nil {
-		return err
-	}
-	if err := c.f(c.offscreen); err != nil {
-		return err
-	}
-	if IsRunningSlowly() {
-		return nil
+	for i := 0; i < updateCount; i++ {
+		if err := c.offscreen.Clear(); err != nil {
+			return err
+		}
+		setRunningSlowly(i < updateCount-1)
+		if err := c.f(c.offscreen); err != nil {
+			return err
+		}
 	}
 	if err := c.offscreen2.Clear(); err != nil {
 		return err
diff --git a/internal/loop/run.go b/internal/loop/run.go
index dfb7513d8..89941acfe 100644
--- a/internal/loop/run.go
+++ b/internal/loop/run.go
@@ -30,10 +30,6 @@ func IsRunning() bool {
 	return currentRunContext.isRunning()
 }
 
-func IsRunningSlowly() bool {
-	return currentRunContext.isRunningSlowly()
-}
-
 type runContext struct {
 	running        bool
 	fps            int
@@ -81,25 +77,9 @@ func (c *runContext) updateFPS(fps float64) {
 	c.currentFPS = fps
 }
 
-func (c *runContext) isRunningSlowly() bool {
-	c.m.RLock()
-	defer c.m.RUnlock()
-	if !c.running {
-		// TODO: Should panic here?
-		return false
-	}
-	return c.runningSlowly
-}
-
-func (c *runContext) setRunningSlowly(isRunningSlowly bool) {
-	c.m.Lock()
-	defer c.m.Unlock()
-	c.runningSlowly = isRunningSlowly
-}
-
 type GraphicsContext interface {
 	SetSize(width, height int, scale float64) error
-	UpdateAndDraw() error
+	UpdateAndDraw(updateCount int) error
 	Draw() error
 }
 
@@ -161,7 +141,6 @@ func (c *runContext) render(g GraphicsContext) error {
 
 	// If lastUpdated is too old, we assume that screen is not shown.
 	if 5*int64(time.Second)/int64(fps) < n-c.lastUpdated {
-		c.setRunningSlowly(false)
 		c.lastUpdated = n
 		return nil
 	}
@@ -176,12 +155,8 @@ func (c *runContext) render(g GraphicsContext) error {
 		tt = 1
 	}
 	if 1 <= tt {
-		for i := 0; i < tt; i++ {
-			slow := i < tt-1
-			c.setRunningSlowly(slow)
-			if err := g.UpdateAndDraw(); err != nil {
-				return err
-			}
+		if err := g.UpdateAndDraw(tt); err != nil {
+			return err
 		}
 	} else {
 		if err := g.Draw(); err != nil {
diff --git a/run.go b/run.go
index 1830978c4..75eb49840 100644
--- a/run.go
+++ b/run.go
@@ -15,6 +15,8 @@
 package ebiten
 
 import (
+	"sync/atomic"
+
 	"github.com/hajimehoshi/ebiten/internal/loop"
 	"github.com/hajimehoshi/ebiten/internal/ui"
 )
@@ -34,13 +36,25 @@ func CurrentFPS() float64 {
 	return loop.CurrentFPS()
 }
 
+var (
+	isRunningSlowly = int32(0)
+)
+
+func setRunningSlowly(slow bool) {
+	v := int32(0)
+	if slow {
+		v = 1
+	}
+	atomic.StoreInt32(&isRunningSlowly, v)
+}
+
 // IsRunningSlowly returns true if the game is running too slowly to keep 60 FPS of rendering.
 // The game screen is not updated when IsRunningSlowly is true.
 // It is recommended to skip heavy processing, especially drawing, when IsRunningSlowly is true.
 //
 // This function is concurrent-safe.
 func IsRunningSlowly() bool {
-	return loop.IsRunningSlowly()
+	return atomic.LoadInt32(&isRunningSlowly) != 0
 }
 
 // Run runs the game.