internal/atlas: bug fix: ReadPixels crashed when inFrame was false

This change fixes the issue by letting ReadPixels return a channel
and executing this asynchronously when needed.

Closes #2815
This commit is contained in:
Hajime Hoshi 2023-10-19 03:56:24 +09:00
parent 7a921e03da
commit ad51e22252
5 changed files with 104 additions and 15 deletions

View File

@ -539,18 +539,30 @@ func (i *Image) writePixels(pix []byte, region image.Rectangle) {
i.backend.restorable.WritePixels(pixb, r)
}
func (i *Image) ReadPixels(graphicsDriver graphicsdriver.Graphics, pixels []byte, region image.Rectangle) error {
func (i *Image) ReadPixels(graphicsDriver graphicsdriver.Graphics, pixels []byte, region image.Rectangle) chan error {
backendsM.Lock()
defer backendsM.Unlock()
if !inFrame {
panic("atlas: ReadPixels must be called in between BeginFrame and EndFrame")
ch := make(chan error)
deferredM.Lock()
deferred = append(deferred, func() {
ch <- i.readPixels(graphicsDriver, pixels, region)
})
deferredM.Unlock()
return ch
}
// In the tests, BeginFrame might not be called often and then images might not be disposed (#2292).
// To prevent memory leaks, flush the deferred functions here.
flushDeferred()
ch := make(chan error, 1)
ch <- i.readPixels(graphicsDriver, pixels, region)
return ch
}
func (i *Image) readPixels(graphicsDriver graphicsdriver.Graphics, pixels []byte, region image.Rectangle) error {
if i.backend == nil || i.backend.restorable == nil {
for i := range pixels {
pixels[i] = 0

View File

@ -117,7 +117,7 @@ func TestEnsureIsolatedFromSourceBackend(t *testing.T) {
}
pix = make([]byte, 4*size*size)
if err := img4.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, size, size)); err != nil {
if err := <-img4.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, size, size)); err != nil {
t.Fatal(err)
}
for j := 0; j < size; j++ {
@ -212,7 +212,7 @@ func TestReputOnSourceBackend(t *testing.T) {
atlas.PutImagesOnSourceBackendForTesting(ui.Get().GraphicsDriverForTesting())
pix = make([]byte, 4*size*size)
if err := img1.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, size, size)); err != nil {
if err := <-img1.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, size, size)); err != nil {
t.Fatal(err)
}
for j := 0; j < size; j++ {
@ -236,7 +236,7 @@ func TestReputOnSourceBackend(t *testing.T) {
}
pix = make([]byte, 4*size*size)
if err := img1.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, size, size)); err != nil {
if err := <-img1.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, size, size)); err != nil {
t.Fatal(err)
}
for j := 0; j < size; j++ {
@ -324,7 +324,7 @@ func TestExtend(t *testing.T) {
img1.WritePixels(p1, image.Rect(0, 0, w1, h1))
pix0 := make([]byte, 4*w0*h0)
if err := img0.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix0, image.Rect(0, 0, w0, h0)); err != nil {
if err := <-img0.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix0, image.Rect(0, 0, w0, h0)); err != nil {
t.Fatal(err)
}
for j := 0; j < h0; j++ {
@ -343,7 +343,7 @@ func TestExtend(t *testing.T) {
}
pix1 := make([]byte, 4*w1*h1)
if err := img1.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix1, image.Rect(0, 0, w1, h1)); err != nil {
if err := <-img1.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix1, image.Rect(0, 0, w1, h1)); err != nil {
t.Fatal(err)
}
for j := 0; j < h1; j++ {
@ -385,7 +385,7 @@ func TestWritePixelsAfterDrawTriangles(t *testing.T) {
dst.WritePixels(pix, image.Rect(0, 0, w, h))
pix = make([]byte, 4*w*h)
if err := dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
if err := <-dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
t.Fatal(err)
}
for j := 0; j < h; j++ {
@ -427,7 +427,7 @@ func TestSmallImages(t *testing.T) {
dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
pix = make([]byte, 4*w*h)
if err := dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
if err := <-dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
t.Fatal(err)
}
for j := 0; j < h; j++ {
@ -470,7 +470,7 @@ func TestLongImages(t *testing.T) {
dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
pix = make([]byte, 4*dstW*dstH)
if err := dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, dstW, dstH)); err != nil {
if err := <-dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, dstW, dstH)); err != nil {
t.Fatal(err)
}
for j := 0; j < h; j++ {
@ -684,7 +684,7 @@ func TestImageWritePixelsModify(t *testing.T) {
// Check the pixels are the original ones.
pix = make([]byte, 4*size*size)
if err := img.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, size, size)); err != nil {
if err := <-img.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, size, size)); err != nil {
t.Fatal(err)
}
for j := 0; j < size; j++ {

View File

@ -44,7 +44,7 @@ func TestShaderFillTwice(t *testing.T) {
dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, s1, nil, false)
pix := make([]byte, 4*w*h)
if err := dst.ReadPixels(g, pix, image.Rect(0, 0, w, h)); err != nil {
if err := <-dst.ReadPixels(g, pix, image.Rect(0, 0, w, h)); err != nil {
t.Error(err)
}
if got, want := (color.RGBA{R: pix[0], G: pix[1], B: pix[2], A: pix[3]}), (color.RGBA{R: 0x80, G: 0x80, B: 0x80, A: 0xff}); got != want {
@ -71,7 +71,7 @@ func TestImageDrawTwice(t *testing.T) {
dst.DrawTriangles([graphics.ShaderImageCount]*atlas.Image{src1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, false)
pix := make([]byte, 4*w*h)
if err := dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
if err := <-dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
t.Error(err)
}
if got, want := (color.RGBA{R: pix[0], G: pix[1], B: pix[2], A: pix[3]}), (color.RGBA{R: 0x80, G: 0x80, B: 0x80, A: 0xff}); got != want {

View File

@ -58,9 +58,14 @@ func (i *Image) MarkDisposed() {
}
func (i *Image) ReadPixels(graphicsDriver graphicsdriver.Graphics, pixels []byte, region image.Rectangle) error {
// If this function is called from the game (Update/Draw) goroutine, and after EndFrame and before BeginFrame,
// (*atlas.Image).ReadPixels's channel never returns a value and causes a dead lock.
// It is assumed that this never happens so far, but if handling inputs after EndFrame is implemented,
// this might be possible (#1704).
// If restorable.AlwaysReadPixelsFromGPU() returns false, the pixel data is cached in the restorable package.
if !restorable.AlwaysReadPixelsFromGPU() {
if err := i.img.ReadPixels(graphicsDriver, pixels, region); err != nil {
if err := <-i.img.ReadPixels(graphicsDriver, pixels, region); err != nil {
return err
}
return nil
@ -68,7 +73,7 @@ func (i *Image) ReadPixels(graphicsDriver graphicsdriver.Graphics, pixels []byte
if i.pixels == nil {
pix := make([]byte, 4*i.width*i.height)
if err := i.img.ReadPixels(graphicsDriver, pix, image.Rect(0, 0, i.width, i.height)); err != nil {
if err := <-i.img.ReadPixels(graphicsDriver, pix, image.Rect(0, 0, i.width, i.height)); err != nil {
return err
}
i.pixels = pix

View File

@ -0,0 +1,72 @@
// Copyright 2023 The Ebitengine Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//go:build ignore
package main
import (
"time"
"github.com/hajimehoshi/ebiten/v2"
)
type Game struct {
init bool
count int
end0 chan struct{}
end1 chan struct{}
}
func (g *Game) Update() error {
if !g.init {
g.end0 = make(chan struct{})
g.end1 = make(chan struct{})
img := ebiten.NewImage(1, 1)
go func() {
t := time.Tick(time.Microsecond)
loop:
for {
select {
case <-t:
img.At(0, 0)
case <-g.end0:
close(g.end1)
break loop
}
}
}()
g.init = true
}
g.count++
if g.count >= 60 {
close(g.end0)
<-g.end1
return ebiten.Termination
}
return nil
}
func (g *Game) Draw(screen *ebiten.Image) {
}
func (g *Game) Layout(w, h int) (int, int) {
return 320, 240
}
func main() {
if err := ebiten.RunGame(&Game{}); err != nil {
panic(err)
}
}