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internal/restorable: reuse byte slices for restoring

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Updates #2375
This commit is contained in:
Hajime Hoshi 2022-10-06 14:52:16 +09:00
parent 85d8a5889a
commit e66bac5c3f
1 changed files with 27 additions and 4 deletions
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31
internal/restorable/image.go
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@ -122,6 +122,17 @@ type Image struct {
// staleRegion is valid only when stale is true.
staleRegion image.Rectangle
// pixelsForRestore is a cached byte slice for pixels.
// pixelsForRestore is just a cache to avoid allocations, and the data might not be reliable.
//
// pixelsForRestore might be shared by the records of basePixels.
// pixelsForRestore should not be modified until basePixels is invalidated.
//
// pixelsForRestore is an entire pixels of the image or nil.
//
// pixelsForRestore is for an optimization to reduce slice allocations (#2375).
pixelsForRestore []byte
imageType ImageType
// priority indicates whether the image is restored in high priority when context-lost happens.
@ -481,7 +492,16 @@ func (i *Image) readPixelsFromGPU(graphicsDriver graphicsdriver.Graphics) error
r = image.Rect(0, 0, i.width, i.height)
}
if !r.Empty() {
pix := make([]byte, 4*r.Dx()*r.Dy())
var pix []byte
if r == image.Rect(0, 0, i.width, i.height) {
// pixelsForRestore can be reused as basePixels was invalidated.
if i.pixelsForRestore == nil {
i.pixelsForRestore = make([]byte, 4*r.Dx()*r.Dy())
}
pix = i.pixelsForRestore
} else {
pix = make([]byte, 4*r.Dx()*r.Dy())
}
if err := i.image.ReadPixels(graphicsDriver, pix, r.Min.X, r.Min.Y, r.Dx(), r.Dy()); err != nil {
return err
}
@ -604,11 +624,14 @@ func (i *Image) restore(graphicsDriver graphicsdriver.Graphics) error {
if len(i.drawTrianglesHistory) > 0 {
i.basePixels = Pixels{}
pix := make([]byte, 4*w*h)
if err := gimg.ReadPixels(graphicsDriver, pix, 0, 0, w, h); err != nil {
// As basePixels was invalidated, pixelsForRestore can be reused.
if i.pixelsForRestore == nil {
i.pixelsForRestore = make([]byte, 4*w*h)
}
if err := gimg.ReadPixels(graphicsDriver, i.pixelsForRestore, 0, 0, w, h); err != nil {
return err
}
i.basePixels.AddOrReplace(pix, 0, 0, w, h)
i.basePixels.AddOrReplace(i.pixelsForRestore, 0, 0, w, h)
}
i.image = gimg