From 58f5c9c1d08729505b4bd45be9f49f86f973316d Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 24 Feb 2018 23:51:05 +0900
Subject: [PATCH] graphics: Refactoring: clearing framebuffer

---
 graphicscontext.go           |  5 ++++-
 image.go                     |  4 ++--
 internal/restorable/image.go | 25 ++++++++++---------------
 3 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/graphicscontext.go b/graphicscontext.go
index 7799237ee..e316466a3 100644
--- a/graphicscontext.go
+++ b/graphicscontext.go
@@ -17,6 +17,7 @@ package ebiten
 import (
 	"github.com/hajimehoshi/ebiten/internal/clock"
 	"github.com/hajimehoshi/ebiten/internal/hooks"
+	"github.com/hajimehoshi/ebiten/internal/math"
 	"github.com/hajimehoshi/ebiten/internal/restorable"
 	"github.com/hajimehoshi/ebiten/internal/ui"
 	"github.com/hajimehoshi/ebiten/internal/web"
@@ -58,7 +59,9 @@ func (c *graphicsContext) SetSize(screenWidth, screenHeight int, screenScale flo
 	w := int(float64(screenWidth) * screenScale)
 	h := int(float64(screenHeight) * screenScale)
 	px0, py0, px1, py1 := ui.ScreenPadding()
-	c.screen = newImageWithScreenFramebuffer(w, h, px0, py0, px1, py1)
+	fw := math.NextPowerOf2Int(w + int(px0+px1))
+	fh := math.NextPowerOf2Int(h + int(py0+py1))
+	c.screen = newImageWithScreenFramebuffer(w, h, fw, fh)
 	_ = c.screen.Clear()
 
 	c.offscreen = offscreen
diff --git a/image.go b/image.go
index 43052df3e..ce174669c 100644
--- a/image.go
+++ b/image.go
@@ -382,9 +382,9 @@ func NewImageFromImage(source image.Image, filter Filter) (*Image, error) {
 	return i, nil
 }
 
-func newImageWithScreenFramebuffer(width, height int, paddingX0, paddingY0, paddingX1, paddingY1 float64) *Image {
+func newImageWithScreenFramebuffer(width, height, framebufferWidth, framebufferHeight int) *Image {
 	checkSize(width, height)
-	r := restorable.NewScreenFramebufferImage(width, height, paddingX0, paddingY0, paddingX1, paddingY1)
+	r := restorable.NewScreenFramebufferImage(width, height, framebufferWidth, framebufferHeight)
 	i := &Image{r, FilterDefault}
 	runtime.SetFinalizer(i, (*Image).Dispose)
 	return i
diff --git a/internal/restorable/image.go b/internal/restorable/image.go
index 89cd6cb9d..c8f28dd83 100644
--- a/internal/restorable/image.go
+++ b/internal/restorable/image.go
@@ -80,10 +80,8 @@ type Image struct {
 	// screen indicates whether the image is used as an actual screen.
 	screen bool
 
-	paddingX0 float64
-	paddingY0 float64
-	paddingX1 float64
-	paddingY1 float64
+	framebufferWidth  int
+	framebufferHeight int
 }
 
 // NewImage creates an empty image with the given size.
@@ -117,15 +115,13 @@ func NewImageFromImage(source image.Image) *Image {
 }
 
 // NewScreenFramebufferImage creates a special image that framebuffer is one for the screen.
-func NewScreenFramebufferImage(width, height int, paddingX0, paddingY0, paddingX1, paddingY1 float64) *Image {
+func NewScreenFramebufferImage(width, height, framebufferWidth, framebufferHeight int) *Image {
 	i := &Image{
-		image:     graphics.NewScreenFramebufferImage(width, height),
-		volatile:  true,
-		screen:    true,
-		paddingX0: paddingX0,
-		paddingY0: paddingY0,
-		paddingX1: paddingX1,
-		paddingY1: paddingY1,
+		image:             graphics.NewScreenFramebufferImage(width, height),
+		volatile:          true,
+		screen:            true,
+		framebufferWidth:  framebufferWidth,
+		framebufferHeight: framebufferHeight,
 	}
 	theImages.add(i)
 	runtime.SetFinalizer(i, (*Image).Dispose)
@@ -170,11 +166,10 @@ func (i *Image) clearIfVolatile() {
 		panic("not reached")
 	}
 
-	w, h := i.image.Size()
 	x0 := float32(0)
 	y0 := float32(0)
-	x1 := float32(w) + float32(i.paddingX0+i.paddingX1)
-	y1 := float32(h) + float32(i.paddingY0+i.paddingY1)
+	x1 := float32(i.framebufferWidth)
+	y1 := float32(i.framebufferHeight)
 	// For the rule of values, see vertices.go.
 	clearVertices := []float32{
 		x0, y0, 0, 0, 1, 1,