Categories: Firefox

Mozilla Games Technology Roadmap

In furthering the advantages and appeal of the Web as a platform for games and game technologies, Mozilla is publishing its games-focused roadmap. In short, it’s all about high-performance, plugin-free games on the Web. We have made incredible progress over the last few years; to continue this trend, Mozilla has been working with game developers and tool makers to identify additional enhancements that will further empower the community. The following roadmap outlines both the feedback we received and the solutions we are currently pursuing in response to this feedback. This roadmap may be subject to change.

With the unveiling of WebAssembly, browsers have taken another common step towards native levels of performance on the Web. This roadmap outlines the wider view of additional Web platform functionality needed to allow game developers to provide the best possible experiences. Games are often a great catalyst for driving technology forward due to their demanding nature. To maximize the benefit to the Web, care has been taken to ensure that solutions will benefit the widest possible range of applications.

There are two levels to this document. The first is the Roadmap section which contains areas that are currently in development and we have a reasonable level of confidence we can address in the next year. The second is the Under Consideration section which contains topics that are under active investigation.


  • Allow developers to better exploit hardware parallelism.
    • Developers are struggling to get multi-threaded games running efficiently on the Web:
      • Standardize, implement and ship SharedArrayBuffer [1,2].
      • Add pthreads support to Emscripten [1,2].
      • Expose performance-sensitive Web APIs to Web Workers: WebGL, WebSockets, IndexedDB, WebAudio, WebRTC, WebVR.
      • Share compiled code (asm.js and WebAssembly) between workers [1].
    • Developers want to take advantage of SIMD hardware to optimize their code:
      • Standardize, implement and ship SIMD.js [1,2].
      • Include SIMD in WebAssembly [1].
      • Add SIMD support to Emscripten [1].
  • Improve cold load time of large compiled codebases.
    • Developers want to see reduced download, compilation and startup time for multi-million line compiled codebases.
      • WebAssembly will provide significant download size reductions (even before native support, through the polyfill) [1].
      • Natively decoding WebAssembly will be significantly faster than parsing JavaScript/asm.js [1].
      • Add a fast WebAssembly/asm.js compiler that allows an app to start quickly while a fully-optimizing compilation proceeds in a background thread [1].
      • Off-main-thread, streaming parsing/compilation [1].
    • Developers want to avoid depending on HTTP Content-Encoding:gzip for generic compression.
      • Add Emscripten support to perform decompression in asm.js / WebAssembly while downloading (allowing more aggressive algorithms than gzip).
  • Improve browser storage capabilities.
    • Developers seeking to avoid the permission prompt associated with persistent storage hit limitations of temporary storage as currently implemented in browsers.
      • Improve temporary quota limits to take into account factors like frecency.
      • Provide more information on quota usage and allowance [1].
      • Propose, standardize and implement finer-granularity units of evictable storage [1].
      • Allow cross-origin storage usage [1].
    • Developers that need persistent storage guarantees hit limitations of persistent storage as currently implemented in browsers.
      • Standardize persistent storage so that other browsers implement [1].
      • Reduce UI friction associated with the persistent permission prompt [1].
      • Improve storage management/eviction UI for browser users.
  • Improve browser graphics capabilities.
    • Ship WebGL2 [1].
    • Standardize and implement streaming WebGL canvas via WebRTC [1,2].
    • Run WebGL on discrete hardware for systems with integrated+discrete (e.g. nVidia Optimus).
  • Allow developers to better avoid 32-bit browser Out-of-Memory conditions.
    • Ship 64-bit Firefox on 64-bit Windows.
    • Avoid Emscripten in-memory Virtual File System for asset storage by leveraging pthreads and FileReaderSync to provide synchronous file I/O in workers.
  • Continue investment in performance across the platform.
    • Significantly optimize WebAudio performance [1].
    • Reduce WebGL shader compile times [1,2].
    • Reduce latency and jitter in the browser’s rendering pipeline [1,2,3,4].
    • Continue investments in the performance of JS, DOM, WebGL, WebRTC, codec, layout, rendering, compositing, animation, etc.
  • Continue investment in Emscripten.
    • Add support for pthreads, SIMD, and WebAssembly, as mentioned above.
    • Further improve compilation speed.
  • Continue investment in Firefox developer tooling to better support game developers.
    • Improve Web Worker support [1].
    • Allow developers to break on various asm.js/WebAssembly error conditions [1].

Under Consideration

  • Developers are having trouble identifying how many Web Workers they should create to distribute their workload. Benchmarking methods often prove unreliable.
  • Developers are hitting the 20-per-origin limit on web workers in Firefox and are requesting a much higher limit.
  • Leverage multi-process browser architecture to guarantee a fresh address space for games with large contiguous heaps allocated early in process startup.
  • Investigate Out-of-Memory error reporting mechanism to send safe/sanitized triage information back to Web app developers.
  • Collaborate on new standards to improve IME capabilities [1,2].
  • Add hardware cursor API [1].
  • Improve Gamepad API [1].
  • Add Pointer Clipping extension to Pointer Lock API [1].
  • Add Emscripten tooling for memory use/leak debugging.
  • Standardize (as part of WebAssembly or more generally) a more scalable form of source maps suitable for large compiled codes.