Stage3D APIs for GPU-accelerated graphics: Away3D: GPU-accelerated 3D graphics and animation engine Starling: GPU-accelerated 2D graphics that mimics the Flash display list API Feathers: GPU-accelerated skinnable GUI library built on top of Starling Dragon Bones: GPU-accelerated 2D skeletal animation library A few commercial game engines target Flash Player (Stage3D) as run-time environment, such as Unity 3D and Unreal Engine 3. Before the introduction of Stage3D, a number of older 2D engines or isometric engines like Flixel saw their heyday. Adobe also developed the CrossBridge toolkit which cross-compiles C/C++ code to run within the Flash Player, using LLVM and GCC as compiler backends, and high-performance memory-access opcodes in the Flash Player (termed "Domain Memory") to work with in-memory data quickly. CrossBridge is targeted toward the game development industry, and includes tools for building, testing, and debugging C/C++ projects in Flash Player. Notable online video games developed in Flash include Angry Birds, FarmVille, and AdventureQuest (started in 2002, and still active as of 2020). Availability Desktop platforms Adobe Flash Player is available in two major flavors: The plugin version for use in various web browsers The "projector" version is a standalone player that can open SWF files directly. On February 22, 2012, Adobe announced that it would no longer release new versions of NPAPI Flash plugins for Linux, although Flash Player 11.2 would continue to receive security updates. In August 2016 Adobe announced that, beginning with version 24, it will resume offering of Flash Player for Linux for other browsers. The Extended Support Release (ESR) of Flash Player on macOS and Windows was a version of Flash Player kept up to date with security updates, but none of the new features or bug fixes available in later versions. In August 2016, Adobe discontinued the ESR branch and instead focused solely on the standard release. Version 10 can be run under Windows 98/Me using KernelEx. HP offered Version 6 of the player for HP-UX, while Innotek GmbH offered versions 4 and 5 for OS/2. Other versions of the player have been available at some point for BeOS. Mobile platforms In 2011, Flash Player had emerged as the de facto standard for online video publishing on the desktop, with adaptive bitrate video streaming, DRM, and fullscreen support. On mobile devices, however, after Apple refused to allow the Flash Player within the inbuilt iOS web browser, Adobe changed strategy, enabling Flash content to be delivered