diff --git a/example/alphablending/main.go b/example/alphablending/main.go
index 9104c4e05..1bc3a3740 100644
--- a/example/alphablending/main.go
+++ b/example/alphablending/main.go
@@ -37,16 +37,19 @@ type Game struct {
 
 func (g *Game) Update(gr ebiten.GraphicsContext) error {
 	g.count++
-	g.count %= 120
-	diff := float64(g.count) * 0.5
-	if 60 < g.count {
-		diff = float64(120-g.count) * 0.5
+	g.count %= 600
+	diff := float64(g.count) * 0.2
+	switch {
+	case 480 < g.count:
+		diff = 0
+	case 240 < g.count:
+		diff = float64(480-g.count) * 0.2
 	}
 
 	gr.PushRenderTarget(g.tmpRenderTarget)
 	gr.Clear()
 	for i := 0; i < 10; i++ {
-		geo := ebiten.TranslateGeometry(15+float64(i)*(20+diff), 20)
+		geo := ebiten.TranslateGeometry(15+float64(i)*(diff), 20)
 		clr := ebiten.ScaleColor(color.RGBA{0xff, 0xff, 0xff, 0x80})
 		ebiten.DrawWholeTexture(gr, g.ebitenTexture, geo, clr)
 	}
@@ -54,7 +57,7 @@ func (g *Game) Update(gr ebiten.GraphicsContext) error {
 
 	gr.Fill(color.RGBA{0x00, 0x00, 0x80, 0xff})
 	for i := 0; i < 10; i++ {
-		geo := ebiten.TranslateGeometry(0, float64(i)*(10+diff))
+		geo := ebiten.TranslateGeometry(0, float64(i)*(diff))
 		clr := ebiten.ColorMatrixI()
 		ebiten.DrawWholeTexture(gr, g.tmpRenderTarget.Texture(), geo, clr)
 	}
diff --git a/graphicscontext.go b/graphicscontext.go
index a600d0f0b..2217df931 100644
--- a/graphicscontext.go
+++ b/graphicscontext.go
@@ -96,6 +96,8 @@ func (c *graphicsContext) preUpdate() {
 func (c *graphicsContext) postUpdate() {
 	c.PopRenderTarget()
 
+	// We don't need to clear the default render target (framebuffer).
+	// For the default framebuffer, a special shader is used.
 	scale := float64(c.screenScale)
 	geo := ScaleGeometry(scale, scale)
 	clr := ColorMatrixI()
diff --git a/internal/opengl/rendertarget.go b/internal/opengl/rendertarget.go
index 6534b3bfc..32c56b048 100644
--- a/internal/opengl/rendertarget.go
+++ b/internal/opengl/rendertarget.go
@@ -86,22 +86,15 @@ func createFramebuffer(nativeTexture gl.Texture) (gl.Framebuffer, error) {
 	framebuffer := gl.GenFramebuffer()
 	framebuffer.Bind()
 
-	if err := framebufferTexture(nativeTexture); err != nil {
-		return 0, err
-	}
-
-	return framebuffer, nil
-}
-
-func framebufferTexture(nativeTexture gl.Texture) error {
 	gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, nativeTexture, 0)
 	if gl.CheckFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE {
-		return errors.New("creating framebuffer failed")
+		return 0, errors.New("creating framebuffer failed")
 	}
 
 	gl.ClearColor(0, 0, 0, 0)
 	gl.Clear(gl.COLOR_BUFFER_BIT)
-	return nil
+
+	return framebuffer, nil
 }
 
 func (r *RenderTarget) SetAsViewport() error {