diff --git a/example/blocks/game.go b/example/blocks/game.go
index 1ff719396..bdded8273 100644
--- a/example/blocks/game.go
+++ b/example/blocks/game.go
@@ -3,6 +3,7 @@ package blocks
 import (
 	"github.com/hajimehoshi/go-ebiten/graphics"
 	"github.com/hajimehoshi/go-ebiten/ui"
+	_ "image/png"
 )
 
 type Size struct {
diff --git a/example/blocks/textures.go b/example/blocks/textures.go
index d00eb35b2..9d06bede3 100644
--- a/example/blocks/textures.go
+++ b/example/blocks/textures.go
@@ -3,7 +3,6 @@ package blocks
 import (
 	"github.com/hajimehoshi/go-ebiten/graphics"
 	"image"
-	_ "image/png"
 	"os"
 	"sync"
 )
@@ -64,36 +63,30 @@ func (t *Textures) loop() {
 				if err != nil {
 					panic(err)
 				}
-				ch := t.textureFactory.CreateTexture(
+				id, err := t.textureFactory.CreateTexture(
 					img,
 					graphics.FilterNearest)
-				go func() {
-					e := <-ch
-					if e.Error != nil {
-						panic(e.Error)
-					}
-					t.Lock()
-					defer t.Unlock()
-					t.textures[name] = e.Id
-				}()
+				if err != nil {
+					panic(err)
+				}
+				t.Lock()
+				defer t.Unlock()
+				t.textures[name] = id
 			}()
 		case s := <-t.renderTargetSizes:
 			name := s.name
 			size := s.size
 			go func() {
-				ch := t.textureFactory.CreateRenderTarget(
+				id, err := t.textureFactory.CreateRenderTarget(
 					size.Width,
 					size.Height,
 					graphics.FilterNearest)
-				go func() {
-					e := <-ch
-					if e.Error != nil {
-						panic(e.Error)
-					}
-					t.Lock()
-					defer t.Unlock()
-					t.renderTargets[name] = e.Id
-				}()
+				if err != nil {
+					panic(err)
+				}
+				t.Lock()
+				defer t.Unlock()
+				t.renderTargets[name] = id
 			}()
 		}
 	}
diff --git a/graphics/texture_factory.go b/graphics/texture_factory.go
index bce414c64..40060429e 100644
--- a/graphics/texture_factory.go
+++ b/graphics/texture_factory.go
@@ -17,17 +17,7 @@ type TextureId int
 // all alpha of a render target is maximum.
 type RenderTargetId int
 
-type TextureCreatedEvent struct {
-	Id    TextureId
-	Error error
-}
-
-type RenderTargetCreatedEvent struct {
-	Id    RenderTargetId
-	Error error
-}
-
 type TextureFactory interface {
-	CreateRenderTarget(width, height int, filter Filter) <-chan RenderTargetCreatedEvent
-	CreateTexture(img image.Image, filter Filter) <-chan TextureCreatedEvent
+	CreateRenderTarget(width, height int, filter Filter) (RenderTargetId, error)
+	CreateTexture(img image.Image, filter Filter) (TextureId, error)
 }
diff --git a/ui/cocoa/shared_context.go b/ui/cocoa/shared_context.go
index 485fe6548..a56b0e407 100644
--- a/ui/cocoa/shared_context.go
+++ b/ui/cocoa/shared_context.go
@@ -73,40 +73,24 @@ func (t *sharedContext) createGameWindow(width, height, scale int, title string)
 
 func (t *sharedContext) CreateTexture(
 	img image.Image,
-	filter graphics.Filter) <-chan graphics.TextureCreatedEvent {
-	ch := make(chan graphics.TextureCreatedEvent)
-	go func() {
-		<-t.inited
-		var id graphics.TextureId
-		var err error
-		t.useGLContext(func() {
-			id, err = opengl.CreateTexture(img, filter)
-		})
-		ch <- graphics.TextureCreatedEvent{
-			Id:    id,
-			Error: err,
-		}
-		close(ch)
-	}()
-	return ch
+	filter graphics.Filter) (graphics.TextureId, error) {
+	<-t.inited
+	var id graphics.TextureId
+	var err error
+	t.useGLContext(func() {
+		id, err = opengl.CreateTexture(img, filter)
+	})
+	return id, err
 }
 
 func (t *sharedContext) CreateRenderTarget(
 	width, height int,
-	filter graphics.Filter) <-chan graphics.RenderTargetCreatedEvent {
-	ch := make(chan graphics.RenderTargetCreatedEvent)
-	go func() {
-		<-t.inited
-		var id graphics.RenderTargetId
-		var err error
-		t.useGLContext(func() {
-			id, err = opengl.CreateRenderTarget(width, height, filter)
-		})
-		ch <- graphics.RenderTargetCreatedEvent{
-			Id:    id,
-			Error: err,
-		}
-		close(ch)
-	}()
-	return ch
+	filter graphics.Filter) (graphics.RenderTargetId, error) {
+	<-t.inited
+	var id graphics.RenderTargetId
+	var err error
+	t.useGLContext(func() {
+		id, err = opengl.CreateRenderTarget(width, height, filter)
+	})
+	return id, err
 }