Optimised, high-performance, multi-threaded rendering pipeline

Felix Bembrick felix.bembrick at gmail.com
Fri Nov 11 11:01:23 UTC 2016

Hi Tobi,

Thanks for the input.

In answer to your first question, not all toolkits use as much parallelisation as HPR but are indeed more performant than JavaFX for a few reasons:

1. They are "closer to the metal". The more layers of architecture you add, there is almost an inevitable performance hit associated with them. There's an OpenGL toolkit named Visualization Library which is very low-level and  the performance is outstanding (and is basically single threaded).

2. The structure of the scene graph. The more cumbersome or memory-hogging the scene graph along with the actual "scene graph model" used can seriously impair the ability to optimise the rendering  pipeline. That's why it was necessary for us to restructure the JavaFX scene graph itself.

3. Significant performance improvements can be achieved (even in a single threaded pipeline) simply by batching GPU commands or using various forms of "caching" them on the GPU (as both OpenGL and Direct3D support). JavaFX is particularly poor in this area of CPU-to-GPU communication.

Now, as for testing HPR with DemoFX, the answer is no.

There are 2 main reasons:

1. HPR currently only works with Java/JavaFX 9 (and that is unlikely to change).

2. Given that DemoFX is mostly Canvas based (along with some 3D scene overlays), I doubt it would have much impact (although I expect the 3D parts would perform better).

I hope these answers are helpful.



> On 11 Nov. 2016, at 21:27, Tobi <tobi at ultramixer.com> wrote:
> Hi,
> thanks Felix, Laurent and Chris for sharing your stuff with the community!
> I am happy to see starting a discussion about boosting up the JavaFX rendering performance. I can confirm that the performance of JavaFX scene graph is not there where it should be. So multithreading would be an excellent, but difficult approach.
> Felix, concerning your research of other toolkits: Do they all use multithreading or are there any toolkits which use single threading but are faster than JavaFX?
> So maybe there are other points than multithreading where we can boost the performance?
> 2) your HPR sounds great. Did you already try DemoFX (part 3) benchmark with your HPR? 
> Best regards,
> Tobi
>> Am 10.11.2016 um 19:11 schrieb Felix Bembrick <felix.bembrick at gmail.com>:
>> (Thanks to Kevin for lifting my "awaiting moderation" impasse).
>> So, with all the recent discussions regarding the great contribution by
>> Laurent Bourgès of MarlinFX, it was suggested that a separate thread be
>> started to discuss parallelisation of the JavaFX rendering pipeline in
>> general.
>> As has been correctly pointed-out, converting or modifying the existing
>> rendering pipeline into a fully multi-threaded and performant beast is
>> indeed quite a complex task.
>> But, that's exactly what myself and my colleagues have been working on for
>> about 2 years.
>> The result is what we call the Hyper Rendering Pipeline (HPR).
>> Work on HPR started when we developed FXMark and were (bitterly)
>> disappointed with the performance of the JavaFX scene graph.  Many JavaFX
>> developers have blogged about the need to dramatically minimise the number
>> of nodes (especially on embedded devices) in order to achieve even
>> "acceptable" performance.  Often it is the case that most (if not all
>> rendering) is eventually done in a single Canvas node.
>> Now, as well already know, the JavaFX Canvas does perform very well and the
>> recent awesome work (DemoFX) by Chris Newland, just for example, shows what
>> can be done with this one node.
>> But, the majority of the animation plumbing in JavaFX is related to the
>> scene graph itself and is designed to make use of multiple nodes and node
>> types.  At the moment, the performance of this scene graph is the Achilles
>> Heel of JavaFX (or at least one of them).
>> Enter HPR.
>> I personally have worked with a number of hardware-accelerated toolkits
>> over the years and am astounded by just how sluggish the rendering pipeline
>> for JavaFX is. When I am animating just a couple of hundred nodes using
>> JavaFX and transitions, I am lucky to get more than about 30 FPS, but on
>> the same (very powerful) machine, I can use other toolkits to render
>> thousands of "objects" and achieve frame rates well over 1000 FPS.
>> So, we refactored the entire scene graph rendering pipeline with the
>> following goals and principles:
>> 1. It is written using JavaFX 9 and Java 9 (but could theoretically be
>> back-ported to JavaFX 8 though I see no reason to).
>> 2. We analysed how other toolkits had optimised their own rendering
>> pipelines (especially Qt which has made some significant advances in this
>> area in recent years).  We also analysed recent examples of multi-threaded
>> rendering using the new Vulkan API.
>> 3. We carefully analysed and determined which parts of the pipeline should
>> best utilise the CPU and which parts should best utilise the GPU.
>> 4. For those parts most suited to the CPU, we use the advanced concurrency
>> features of Java 8/9 to maximise parallelisation and throughput by
>> utilising multiple cores & threads in as an efficient manner as possible.
>> 5. We devoted a large amount of time to optimising the "communication"
>> between the CPU and GPU to be far less "chatty" and this alone led to some
>> huge performance gains.
>> 6. We also looked at the structure of the scene graph itself and after
>> studying products such as OpenSceneGraph, we refactored the JavaFX scene
>> graph in such a way that it lends itself to optimised rendering much more
>> easily.
>> 7. This is clearly not a "small" patch.  In fact to refer to it as a
>> "patch" is probably rather inappropriate.
>> The end result is that we now have a fully-functional prototype of HPR and,
>> already, we are seeing very significant performance improvements.
>> At the minimum, scene graph rendering performance has improved by 500% and,
>> with judicious and sometimes "tricky" use of caching, we have seen
>> improvements in performance of 10x or more.
>> And... we are only just *starting* with the performance optimisation phase.
>> The potential for HPR is massive as it opens-up the possibility for the
>> JavaFX scene graph and the animation/transition infrastructure to be used
>> for a whole new class of applications including games, advanced
>> visualisations etc., without having to rely on imperative programming of a
>> single Canvas node.
>> I believe that HPR, along with tremendous recent developments like JPro and
>> the outstanding work by Gluon on mobiles and embedded devices, could
>> position JavaFX to be the best graphics toolkit of any kind in any language
>> and, be the ONLY *truly* cross-platform graphics technology available.
>> WORA for graphics and UIs is finally within reach!
>> Blessings,
>> Felix

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