restorable: Reland: Refactoring

internal/restorable/image.go

@@ -301,7 +301,7 @@ func (i *Image) ReplacePixels(pixels []byte, x, y, width, height int) {
 	}
 	i.image.ReplacePixels(pixels, x, y, width, height)
 
-	if !NeedsRestoring() {
+	if !needsRestoring() {
 		i.makeStale()
 		return
 	}
@@ -362,7 +362,7 @@ func (i *Image) DrawTriangles(img *Image, vertices []float32, indices []uint16,
 	}
 	theImages.makeStaleIfDependingOn(i)
 
-	if img.stale || img.volatile || i.screen || !NeedsRestoring() || i.volatile {
+	if img.stale || img.volatile || i.screen || !needsRestoring() || i.volatile {
 		i.makeStale()
 	} else {
 		i.appendDrawTrianglesHistory(img, vertices, indices, colorm, mode, filter, address)
@@ -447,7 +447,7 @@ func (i *Image) readPixelsFromGPU() {
 
 // resolveStale resolves the image's 'stale' state.
 func (i *Image) resolveStale() {
-	if !NeedsRestoring() {
+	if !needsRestoring() {
 		return
 	}
 
@@ -551,15 +551,11 @@ func (i *Image) Dispose() {
 	i.stale = false
 }
 
-// IsInvalidated returns a boolean value indicating whether the image is invalidated.
+// isInvalidated returns a boolean value indicating whether the image is invalidated.
 //
 // If an image is invalidated, GL context is lost and all the images should be restored asap.
-func (i *Image) IsInvalidated() (bool, error) {
+func (i *Image) isInvalidated() bool {
 	// FlushCommands is required because c.offscreen.impl might not have an actual texture.
 	graphicscommand.FlushCommands()
-	if !NeedsRestoring() {
+	return i.image.IsInvalidated()
-		return false, nil
-	}
-
-	return i.image.IsInvalidated(), nil
 }

internal/restorable/images.go

@@ -23,8 +23,8 @@ import (
 // forceRestoring reports whether restoring forcely happens or not.
 var forceRestoring = false
 
-// NeedsRestoring reports whether restoring process works or not.
+// needsRestoring reports whether restoring process works or not.
-func NeedsRestoring() bool {
+func needsRestoring() bool {
 	if forceRestoring {
 		return true
 	}
@@ -53,16 +53,33 @@ var theImages = &images{
 // ResolveStaleImages is intended to be called at the end of a frame.
 func ResolveStaleImages() {
 	graphicscommand.FlushCommands()
-	if !NeedsRestoring() {
+	if !needsRestoring() {
 		return
 	}
 	theImages.resolveStaleImages()
 }
 
-// Restore restores the images.
+// RestoreIfNeeded restores the images.
 //
 // Restoring means to make all *graphicscommand.Image objects have their textures and framebuffers.
-func Restore() error {
+func RestoreIfNeeded() error {
+	if !needsRestoring() {
+		return nil
+	}
+
+	if !forceRestoring {
+		r := false
+		// As isInvalidated() is expensive, call this only for one image.
+		// This assumes that if there is one image that is invalidated, all images are invalidated.
+		for img := range theImages.images {
+			r = img.isInvalidated()
+			break
+		}
+		if !r {
+			return nil
+		}
+	}
+
 	if err := graphicscommand.ResetGraphicsDriverState(); err != nil {
 		return err
 	}
@@ -144,7 +161,7 @@ func (i *images) makeStaleIfDependingOnImpl(target *Image) {
 //
 // Restoring means to make all *graphicscommand.Image objects have their textures and framebuffers.
 func (i *images) restore() error {
-	if !NeedsRestoring() {
+	if !needsRestoring() {
 		panic("restorable: restore cannot be called when restoring is disabled")
 	}
 

internal/restorable/images_test.go

@@ -75,7 +75,7 @@ func TestRestore(t *testing.T) {
 	clr0 := color.RGBA{0x00, 0x00, 0x00, 0xff}
 	img0.Fill(clr0.R, clr0.G, clr0.B, clr0.A)
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	want := clr0
@@ -92,7 +92,7 @@ func TestRestoreWithoutDraw(t *testing.T) {
 	// If there is no drawing command on img0, img0 is cleared when restored.
 
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 
@@ -131,7 +131,7 @@ func TestRestoreChain(t *testing.T) {
 		imgs[i+1].DrawTriangles(imgs[i], vs, is, nil, graphics.CompositeModeCopy, graphics.FilterNearest, graphics.AddressClampToZero)
 	}
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	want := clr
@@ -175,7 +175,7 @@ func TestRestoreChain2(t *testing.T) {
 	}
 
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	for i, img := range imgs {
@@ -214,7 +214,7 @@ func TestRestoreOverrideSource(t *testing.T) {
 	img0.Fill(clr1.R, clr1.G, clr1.B, clr1.A)
 	img1.DrawTriangles(img0, quadVertices(img0, w, h, 0, 0), is, nil, graphics.CompositeModeSourceOver, graphics.FilterNearest, graphics.AddressClampToZero)
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	testCases := []struct {
@@ -307,7 +307,7 @@ func TestRestoreComplexGraph(t *testing.T) {
 	vs = quadVertices(img3, w, h, 2, 0)
 	img7.DrawTriangles(img3, vs, is, nil, graphics.CompositeModeSourceOver, graphics.FilterNearest, graphics.AddressClampToZero)
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	testCases := []struct {
@@ -398,7 +398,7 @@ func TestRestoreRecursive(t *testing.T) {
 	img1.DrawTriangles(img0, quadVertices(img0, w, h, 1, 0), is, nil, graphics.CompositeModeSourceOver, graphics.FilterNearest, graphics.AddressClampToZero)
 	img0.DrawTriangles(img1, quadVertices(img1, w, h, 1, 0), is, nil, graphics.CompositeModeSourceOver, graphics.FilterNearest, graphics.AddressClampToZero)
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	testCases := []struct {
@@ -452,7 +452,7 @@ func TestReplacePixels(t *testing.T) {
 		}
 	}
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	for j := 7; j < 11; j++ {
@@ -484,7 +484,7 @@ func TestDrawTrianglesAndReplacePixels(t *testing.T) {
 	img1.ReplacePixels([]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, 0, 0, 2, 1)
 
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	r, g, b, a := img1.At(0, 0)
@@ -517,7 +517,7 @@ func TestDispose(t *testing.T) {
 	img1.Dispose()
 
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	r, g, b, a := img0.At(0, 0)
@@ -625,7 +625,7 @@ func TestReplacePixelsOnly(t *testing.T) {
 	}
 
 	ResolveStaleImages()
-	if err := Restore(); err != nil {
+	if err := RestoreIfNeeded(); err != nil {
 		t.Fatal(err)
 	}
 	want := color.RGBA{1, 2, 3, 4}

internal/shareable/shareable.go

@@ -404,13 +404,6 @@ func (i *Image) IsVolatile() bool {
 	return i.backend.restorable.IsVolatile()
 }
 
-func (i *Image) IsInvalidated() (bool, error) {
-	backendsM.Lock()
-	defer backendsM.Unlock()
-	v, err := i.backend.restorable.IsInvalidated()
-	return v, err
-}
-
 func NewImage(width, height int) *Image {
 	// Actual allocation is done lazily.
 	return &Image{
@@ -508,15 +501,10 @@ func ResolveStaleImages() {
 	restorable.ResolveStaleImages()
 }
 
-func NeedsRestoring() bool {
+func RestoreIfNeeded() error {
-	// As NeedsRestoring is an immutable state, no need to lock here.
-	return restorable.NeedsRestoring()
-}
-
-func Restore() error {
 	backendsM.Lock()
 	defer backendsM.Unlock()
-	return restorable.Restore()
+	return restorable.RestoreIfNeeded()
 }
 
 func Images() []image.Image {

uicontext.go

@@ -146,22 +146,8 @@ func (c *uiContext) Update(afterFrameUpdate func()) error {
 	return nil
 }
 
-func (c *uiContext) needsRestoring() (bool, error) {
-	return c.offscreen.mipmap.original().IsInvalidated()
-}
-
 func (c *uiContext) restoreIfNeeded() error {
-	if !shareable.NeedsRestoring() {
+	if err := shareable.RestoreIfNeeded(); err != nil {
-		return nil
-	}
-	r, err := c.needsRestoring()
-	if err != nil {
-		return err
-	}
-	if !r {
-		return nil
-	}
-	if err := shareable.Restore(); err != nil {
 		return err
 	}
 	return nil