While I am working on a project with Urho3D, I have found there’s no built-in way to play animated gifs, so I write my own. Since this is a general problem, I’d like to share my work with the community.
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Overview
In the zip file, which can be found at the end of this post, there’re 5 files.
The AnimatedGif.h/cpp defines a new type of Resource. It uses hidefromkgb’s gif_load.h (public domain C library) to decode the gif.
The FrameAnimation.h/cpp defines a new type of component. It uses AnimatedGif to play the animation. -
Usage
(1) copy the files under the same folder and add to your project. If you want to place them separately, change the #include accordingly.
(2) register the types before use, for example in the constructor of your application, write
AnimatedGif::RegisterObject(context);
FrameAnimation::RegisterObject(context);
(3) code as if they are Urho3D built-in types. For example:
//Setup 2D Scene…
auto pPic = _gameScene->CreateChild(“test_gif”);
pPic->SetPosition2D(0, 0);
auto pFrAni = pPic->CreateComponent< FrameAnimation >();
auto pGif = GetSubsystem< ResourceCache >()->GetResource< AnimatedGif >(“Data/Urho2D/test.gif”);
pFrAni->SetGif(pGif);
Check this gif for result. Each time I click the button, a new gif will be created.
(browser may show the gif slower than normal)
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Notice
(1) if the gif is large, consider doing a backgroundloading with resource cache first.
(2) MSVC user: since it uses a C library, you may need to change IDE grammar check from C++ to C.
(3) MSVC user: there’re a lot of comments in CHINESE, which is my mother tongue. They are mostly about background knowledge on the media format, rationale and C library usage. If you just want to play a gif, don’t bother. But you need to change the encoding from UTF-8 to UTF-8 BOM, or else MSVC will output strange errors. Personally I think it’s a flaw in the compiler. Apple Clang and g++ don’t have this issue. Another way is to just remove all comments. -
Download
The forum doesn’t allow zip file uploading, so I have put the file on my website for your access.
https://dins.site/wp-content/uploads/2021/03/gif-addon.zip
The codes are released under MIT license.
Hope this can help some people in the future.
Cheers! 
