pixels: Add 'stale' member

imageimpl.go

@@ -113,9 +113,6 @@ func (i *imageImpl) Fill(clr color.Color) error {
 	if i.disposed {
 		return errors.New("ebiten: image is already disposed")
 	}
-	if i.pixels == nil {
-		i.pixels = pixels.NewPixels(i.image)
-	}
 	i.pixels.Fill(clr)
 	return i.image.Fill(clr)
 }
@@ -129,9 +126,6 @@ func (i *imageImpl) clearIfVolatile() error {
 	if !i.volatile {
 		return nil
 	}
-	if i.pixels == nil {
-		i.pixels = pixels.NewPixels(i.image)
-	}
 	i.pixels.Clear()
 	return i.image.Fill(color.Transparent)
 }
@@ -170,9 +164,7 @@ func (i *imageImpl) DrawImage(image *Image, options *DrawImageOptions) error {
 	geom := options.GeoM
 	colorm := options.ColorM
 	mode := opengl.CompositeMode(options.CompositeMode)
-	if i.pixels != nil {
-		i.pixels.AppendDrawImageHistory(image.impl.image, vertices, &geom, &colorm, mode)
-	}
+	i.pixels.AppendDrawImageHistory(image.impl.image, vertices, &geom, &colorm, mode)
 	if err := i.image.DrawImage(image.impl.image, vertices, &geom, &colorm, mode); err != nil {
 		return err
 	}
@@ -202,10 +194,9 @@ func (i *imageImpl) ensurePixels(context *opengl.Context) error {
 	if i.disposed {
 		return nil
 	}
-	if i.pixels != nil {
+	if !i.pixels.IsStale() {
 		return nil
 	}
-	i.pixels = pixels.NewPixels(i.image)
 	if err := i.pixels.Reset(context); err != nil {
 		return err
 	}
@@ -224,9 +215,6 @@ func (i *imageImpl) resetPixelsIfDependingOn(target *imageImpl, context *opengl.
 	if target.isDisposed() {
 		return errors.New("ebiten: target is already disposed")
 	}
-	if i.pixels == nil {
-		return nil
-	}
 	// target is an image begin tried to mutate.
 	// If pixels object is related to that image, the pixels must be reset.
 	if !i.pixels.DependsOn(target.image) {
@@ -234,7 +222,7 @@ func (i *imageImpl) resetPixelsIfDependingOn(target *imageImpl, context *opengl.
 	}
 	if context == nil {
 		// context is nil when this is not initialized yet.
-		i.pixels = nil
+		i.pixels.MakeStale()
 		return nil
 	}
 	if err := i.pixels.Reset(context); err != nil {
@@ -246,9 +234,6 @@ func (i *imageImpl) resetPixelsIfDependingOn(target *imageImpl, context *opengl.
 func (i *imageImpl) hasDependency() bool {
 	i.m.Lock()
 	defer i.m.Unlock()
-	if i.pixels == nil {
-		return false
-	}
 	return i.pixels.HasDependency()
 }
 
@@ -308,9 +293,6 @@ func (i *imageImpl) ReplacePixels(p []uint8) error {
 	}
 	i.m.Lock()
 	defer i.m.Unlock()
-	if i.pixels == nil {
-		i.pixels = pixels.NewPixels(i.image)
-	}
 	i.pixels.ReplacePixels(p)
 	if i.disposed {
 		return errors.New("ebiten: image is already disposed")

internal/pixels/pixels.go

@@ -38,6 +38,7 @@ type Pixels struct {
 	basePixels       []uint8
 	baseColor        color.Color
 	drawImageHistory []*drawImageHistoryItem
+	stale            bool
 }
 
 func NewPixels(image *graphics.Image) *Pixels {
@@ -46,16 +47,29 @@ func NewPixels(image *graphics.Image) *Pixels {
 	}
 }
 
+func (p *Pixels) IsStale() bool {
+	return p.stale
+}
+
+func (p *Pixels) MakeStale() {
+	p.basePixels = nil
+	p.baseColor = nil
+	p.drawImageHistory = nil
+	p.stale = true
+}
+
 func (p *Pixels) Clear() {
 	p.basePixels = nil
 	p.baseColor = nil
 	p.drawImageHistory = nil
+	p.stale = false
 }
 
 func (p *Pixels) Fill(clr color.Color) {
 	p.basePixels = nil
 	p.baseColor = clr
 	p.drawImageHistory = nil
+	p.stale = false
 }
 
 func (p *Pixels) ReplacePixels(pixels []uint8) {
@@ -65,9 +79,13 @@ func (p *Pixels) ReplacePixels(pixels []uint8) {
 	copy(p.basePixels, pixels)
 	p.baseColor = nil
 	p.drawImageHistory = nil
+	p.stale = false
 }
 
 func (p *Pixels) AppendDrawImageHistory(image *graphics.Image, vertices []int16, geom graphics.Matrix, colorm graphics.Matrix, mode opengl.CompositeMode) {
+	if p.stale {
+		return
+	}
 	item := &drawImageHistoryItem{
 		image:    image,
 		vertices: vertices,
@@ -83,7 +101,7 @@ func (p *Pixels) AppendDrawImageHistory(image *graphics.Image, vertices []int16,
 // Note that this must not be called until context is available.
 // This means Pixels members must match with acutal state in GPU.
 func (p *Pixels) At(idx int, context *opengl.Context) (color.Color, error) {
-	if p.basePixels == nil || p.drawImageHistory != nil {
+	if p.basePixels == nil || p.drawImageHistory != nil || p.stale {
 		if err := p.Reset(context); err != nil {
 			return nil, err
 		}
@@ -93,6 +111,9 @@ func (p *Pixels) At(idx int, context *opengl.Context) (color.Color, error) {
 }
 
 func (p *Pixels) DependsOn(target *graphics.Image) bool {
+	if p.stale {
+		return false
+	}
 	for _, c := range p.drawImageHistory {
 		if c.image == target {
 			return true
@@ -109,10 +130,14 @@ func (p *Pixels) Reset(context *opengl.Context) error {
 	}
 	p.baseColor = nil
 	p.drawImageHistory = nil
+	p.stale = false
 	return nil
 }
 
 func (p *Pixels) HasDependency() bool {
+	if p.stale {
+		return false
+	}
 	return p.drawImageHistory != nil
 }
 
@@ -153,5 +178,6 @@ func (p *Pixels) Restore(context *opengl.Context, width, height int, filter open
 	}
 	p.baseColor = nil
 	p.drawImageHistory = nil
+	p.stale = false
 	return gimg, nil
 }