From 613b9bc02a71a730c7781f9670dbc06bce5caed8 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Mon, 12 Aug 2019 17:45:43 +0900
Subject: [PATCH] restorable: Panic if an image is stale when restoring

---
 internal/restorable/image.go  | 11 ++++-------
 internal/restorable/images.go | 10 ++++------
 2 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/internal/restorable/image.go b/internal/restorable/image.go
index 8aa9dc73a..cc50b0d85 100644
--- a/internal/restorable/image.go
+++ b/internal/restorable/image.go
@@ -15,7 +15,6 @@
 package restorable
 
 import (
-	"errors"
 	"fmt"
 
 	"github.com/hajimehoshi/ebiten/internal/affine"
@@ -525,7 +524,7 @@ func (i *Image) hasDependency() bool {
 }
 
 // Restore restores *graphicscommand.Image from the pixels using its state.
-func (i *Image) restore() error {
+func (i *Image) restore() {
 	w, h := i.Size()
 
 	// Dispose the internal image after getting its size for safety.
@@ -538,16 +537,15 @@ func (i *Image) restore() error {
 		i.basePixels = Pixels{}
 		i.drawTrianglesHistory = nil
 		i.stale = false
-		return nil
+		return
 	}
 	if i.volatile {
 		i.image = graphicscommand.NewImage(w, h)
 		i.clear()
-		return nil
+		return
 	}
 	if i.stale {
-		// TODO: panic here?
-		return errors.New("restorable: pixels must not be stale when restoring")
+		panic("restorable: pixels must not be stale when restoring")
 	}
 
 	gimg := graphicscommand.NewImage(w, h)
@@ -570,7 +568,6 @@ func (i *Image) restore() error {
 	i.image = gimg
 	i.drawTrianglesHistory = nil
 	i.stale = false
-	return nil
 }
 
 // Dispose disposes the image.
diff --git a/internal/restorable/images.go b/internal/restorable/images.go
index 5711eaeea..c26eb7288 100644
--- a/internal/restorable/images.go
+++ b/internal/restorable/images.go
@@ -119,7 +119,8 @@ func RestoreIfNeeded() error {
 	if err := graphicscommand.ResetGraphicsDriverState(); err != nil {
 		return err
 	}
-	return theImages.restore()
+	theImages.restore()
+	return nil
 }
 
 // DumpImages dumps all the current images to the specified directory.
@@ -194,7 +195,7 @@ func (i *images) makeStaleIfDependingOnImpl(target *Image) {
 // restore restores the images.
 //
 // Restoring means to make all *graphicscommand.Image objects have their textures and framebuffers.
-func (i *images) restore() error {
+func (i *images) restore() {
 	if !needsRestoring() {
 		panic("restorable: restore cannot be called when restoring is disabled")
 	}
@@ -251,11 +252,8 @@ func (i *images) restore() error {
 	}
 
 	for _, img := range sorted {
-		if err := img.restore(); err != nil {
-			return err
-		}
+		img.restore()
 	}
-	return nil
 }
 
 // InitializeGraphicsDriverState initializes the graphics driver state.