From 24e20306f2e522a5204cc9849453c27eefd47f56 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Thu, 5 Apr 2018 11:15:24 +0900
Subject: [PATCH] restorable: Move 'putting random-colored dot' to restorable

---
 internal/restorable/image.go    | 25 +++++++++++++++++++++++++
 internal/shareable/shareable.go | 24 ------------------------
 2 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/internal/restorable/image.go b/internal/restorable/image.go
index d99a0149f..ee1698e1b 100644
--- a/internal/restorable/image.go
+++ b/internal/restorable/image.go
@@ -72,6 +72,20 @@ type Image struct {
 	screen bool
 }
 
+type rand struct {
+	x, y, z, w uint32
+}
+
+func (r *rand) next() uint32 {
+	// Xorshift: http://en.wikipedia.org/wiki/Xorshift
+	t := r.x ^ (r.x << 11)
+	r.x, r.y, r.z = r.y, r.z, r.w
+	r.w = (r.w ^ (r.w >> 19)) ^ (t ^ (t >> 8))
+	return r.w
+}
+
+var theRand = &rand{12345678, 4185243, 776511, 45411}
+
 // NewImage creates an empty image with the given size.
 func NewImage(width, height int, volatile bool) *Image {
 	i := &Image{
@@ -80,6 +94,17 @@ func NewImage(width, height int, volatile bool) *Image {
 	}
 	theImages.add(i)
 	runtime.SetFinalizer(i, (*Image).Dispose)
+
+	// Put a random color pixel on newImg to make tests reliable
+	// (e.g. shareable_test.TestEnsureNotShared. This test might pass
+	// without this ReplacePixels even when the next DrawImage has a bug).
+	// This avoids to use remaining GPU memory state unexpectedly.
+	//
+	// TODO: Is it better clearing the image? How about the cost?
+	v := theRand.next()
+	r, g, b := uint8(v>>24), uint8(v>>16), uint8(v>>8)
+	i.ReplacePixels([]byte{r, g, b, 0xff}, 0, 0, 1, 1)
+
 	return i
 }
 
diff --git a/internal/shareable/shareable.go b/internal/shareable/shareable.go
index a4b79789e..953e31ce8 100644
--- a/internal/shareable/shareable.go
+++ b/internal/shareable/shareable.go
@@ -87,20 +87,6 @@ type Image struct {
 	node *packing.Node
 }
 
-type rand struct {
-	x, y, z, w uint32
-}
-
-func (r *rand) next() uint32 {
-	// Xorshift: http://en.wikipedia.org/wiki/Xorshift
-	t := r.x ^ (r.x << 11)
-	r.x, r.y, r.z = r.y, r.z, r.w
-	r.w = (r.w ^ (r.w >> 19)) ^ (t ^ (t >> 8))
-	return r.w
-}
-
-var theRand = &rand{12345678, 4185243, 776511, 45411}
-
 func (s *Image) ensureNotShared() {
 	if s.node == nil {
 		return
@@ -108,16 +94,6 @@ func (s *Image) ensureNotShared() {
 
 	x, y, w, h := s.region()
 	newImg := restorable.NewImage(w, h, false)
-
-	// Put a random color pixel on newImg to make tests reliable.
-	//
-	// Of course this function works without this ReplacePixels,
-	// but the tests might pass without this even if there is a bug
-	// in DrawImage because of previous GPU memory state.
-	v := theRand.next()
-	r, g, b := uint8(v>>24), uint8(v>>16), uint8(v>>8)
-	newImg.ReplacePixels([]byte{r, g, b, 0xff}, 0, 0, 1, 1)
-
 	newImg.DrawImage(s.backend.restorable, x, y, x+w, y+h, nil, nil, opengl.CompositeModeCopy, graphics.FilterNearest)
 
 	s.dispose()