Merge pull request #10985 from dabingnn/v3_fixRenderTextureCrash

fix crash problem when switch to a new scene after call RenderTexture::s...

cocos/2d/CCRenderTexture.h

@@ -107,6 +107,9 @@ public:
 
     /** saves the texture into a file. The format could be JPG or PNG. The file will be saved in the Documents folder.
         Returns true if the operation is successful.
+     Notes: since v3.x, saveToFile will generate a custum command, which will be called in the following render->render().
+     So if this function is called in a event handler, the actual save file will be called in the next frame. If we switch to a different scene, the game will crash.
+     To solve this, add Director::getInstance()->getRenderer()->render(); after this function.
      */
     bool saveToFile(const std::string& filename, Image::Format format, bool isRGBA = true, std::function<void (RenderTexture*, const std::string&)> callback = nullptr);
     

tests/cpp-tests/Classes/RenderTextureTest/RenderTextureTest.cpp

@@ -146,7 +146,8 @@ void RenderTextureSave::saveImage(cocos2d::Ref *sender)
     };
     
     _target->saveToFile(png, Image::Format::PNG, true, callback);
-
+    //Add this function to avoid crash if we switch to a new scene.
+    Director::getInstance()->getRenderer()->render();
     CCLOG("Image saved %s", png);
 
     counter++;