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Vehicle loading changes

Discussion in 'Microblogs' started by tdev, May 8, 2020.

  1. ByteGuy

    ByteGuy
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    Fantastic! I love seeing how the game engine works and I love seeing the improvements being made. Cleaner code is awesome! Like someone else said im wondering if this will allow dynamic traffic - i.e. instead of having a select number of a set type of vehicle will we see different models being dynamically loaded?
     
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  2. Dothero

    Dothero
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    Very interesting ! Show one more time that adding content is not necessarily the most difficult part. Optimisation takes longer, don't give a lot of changes in the next update (players will be more hype with a new car that if we say we change the way vehicles spawns) but it is essential to keep the game going forward. Great job devs !
     
  3. italy0047

    italy0047
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    Aaahh oh amazing:)
     
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  4. Dummiesman

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    Does this have any negative implications for custom vehicle lua? Could it possibly break some things?
     
  5. 77x5ghost

    77x5ghost
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    my i3 6300 approves of this
     
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  6. jwacker1

    jwacker1
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    I'm amazed by all the improvements this game keeps getting, even after 7 years since it's forked from Torque3D. Wonder if there's any new commits to Torque3D that would even benefit your fork with how far it's branched. Sounds like some fun coffee filled debugging days ahead! Good luck, and thanks for the updates
     
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  7. Bubbleawsome

    Bubbleawsome
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    Very cool to see! Thanks for the in depth post
     
  8. SajtistaPista

    SajtistaPista
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    Very nice work!!
     
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  9. tdev

    tdev
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    such_a_great_coffee.jpg
    Good morning for round two :)

    Thanks everyone for your feedback, i'll continue with what is happening in the last days then :)

    Generally speaking, this is optimizing the vehicle loading as a whole and some other parts of the game engine. I want to show you all the details and effort we are undertaking to optimize and improve the GE. Lets see what happened:
    First, some days ago, we optimized the serialize function that send that data to the vehicle Lua. A change like that looks like this: (Top: before optimization, bottom: after. Optimized from ~100 ms to 59 ms)
    opt1.png
    (note that the timing can vary a bit depending on the operating system load, etc at that time)
    Generally, you usually look at the graph, and see what elements could be optimized, work on that little block for a while and make it hopefully faster.
    Ok, then our amazing @LuisAntonRebollo found that we initialize the Materials for the car far too often. Top image: before optimization, bottom after.
    opt2.png
    It was happening at jbeam materials init and twice at the end. We only need two material inits: one for all flexbodies and one for all props.
    This change improved the overall frame time from 1762 ms to 1385.

    Lets see what followed after that. This was a lot of work (the whole weekend):
    opt3.png
    a) we optimized our Filesystem layer (we use a modified physFS btw) to have less calls to the operating system. I.e. fileExist was super slow because it actually tried to open the file - it now uses stat to figure that out a lot faster. We found that findFiles was really slow due to the way the data was handled, and we replaced the syscall FindFileFirstW with the faster version FindFileFirstExW. Temporary memory allocations usually kill the performance really badly. So if you want to write fast code, make sure you don't allocate in the critical path and allocate everything needed upfront - and big enough.
    b) our wizard @estama rewrote the complete serialize and deserialize functions. We initially tried various ways including going to the C++ side of things, but it turns out that the JIT of LuaJIT is a much better fit for this problem. Using it, we are faster in Lua than in C/C++. The serialize (packing of the data into a string) now takes 35 ms and the deserialize (unpacking from string into a lua table) around 48 ms.
    c) Our code master ninja @LuisAntonRebollo found out that the filesystem is really in the way of compiling the material shader permutations. He optimized it to preload the files and have less FS interaction in the critical path.

    These changes reduced the overall frame time from 1386 to 1264 ms :)

    Next up for today:
    d) optimizing the jbeam reading code. We are currently reading and parsing the jbeam of 2711 parts (see attached parts_loaded.json) and we end up using 90 in my testing pickup configuration. (see parts_used.txt)
    That is highly inefficient and calls for optimization. However, it's not as easy to optimize as one might think, as we need to keep the memory usage down to not overload the Lua garbage collector. Rule of thumb is, the more objects/memory lua has to manage, the slower the garbage collection gets to check if something is still in use.
    e) We want to see if we can remove the fmod .bank loading from blocking the main thread.

    Hope you enjoyed the read :)

    Feedback/Comments/Questions ? :)
     

    Attached Files:

    #29 tdev, May 12, 2020
    Last edited: May 12, 2020
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  10. tdev

    tdev
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    Hopefully not, however a lot of stuff is changing right now. If we forgot to add backward compatibility for something, let us know when something breaks and we'll try our best :)
     
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  11. kwai38

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    1. I have no idea what you're saying.
    2. It sounds really good. This is why I love the dev team so much
     
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  12. Wedel 25

    Wedel 25
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    You guys are the best.
    Not only are you trying your best to make everyone's experience better but you are doing it *WHILE* telling us all about your work. Making screenshots and writing a whole, detailed article; this is what I wish all game devs did to give people a little more clarity and a sneak peek behind the scenes of their favourite game. Even though most of us, me included, cannot understand everything you are trying to explain, it is still interesting how the game works besides what happens on the outside. Massive props to you for informing us about the progress. I am excited for the next one. :)
     
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  13. YellowRusty

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    I enjoyed the read, even though I didn't understand most of it on a technical/coding level.

    On another level, it's really good to see all of this work - otherwise it just looks like a single line in a changelog that, for all I know, took two minutes and moving around ten lines of code. Seeing this really increases my appreciation of what the technical side of the dev team does!

    On the side of questions, other than the reason why (All those 'interesting topics' mentioned in the OP, which I understand is probably still under wraps), the main thing I want to know is what impact (if any) this new system for spawing has after the vehicle is spawned - at what point does the physics side take over?
     
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  14. tdev

    tdev
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  15. Drivver

    Drivver
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    Daaamn, that's so amazing to look at, and realize how much happens each frame, then multiply it to "FPS" to imagine how much work is done each second - and that's graphics only, what about physics that's calculated with rate of 2000Hz during that time. o_O

    I think I'd have a blast toying with dev build, (usually much lower fps) looks like it includes very interesting stuff. - and I'd love to see that implemented in public build:

    (from 1:04 to 1:24 ^)

    Anyway it's great that you share those datails, always nice to learn something new. Also makes feel each update to non-visible "under the hood works" more valuable when you're familiarized with it and how much effort have to be put around it, than just a string of text on devblog. Thank you for sharing :)
     
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  16. CaptainZoll

    CaptainZoll
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    I think they've said that the showing of internal parts is a trick with editing software, they take a video of the normal vehicle and a video with the cab/chassis hidden and with one of the debug visualisations turned on, and just sort of mush the two together.
     
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  17. Masterjoc

    Masterjoc
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    Thank you tdev for the insight.
    As a regular player i feel more connected to a game, when getting insights and detailed explanations.
    You end up understanding problems more than usually.

    Wreckfest did actually the same what you are doing now. They have speedup their loading times by miles and everyone freaked out.
    You can expect the same from BeamNG community when this package lands.

    It is just great to see you are attacking important points step by step.
    Thanks for Diamond we know there are coming 3 updates on how the car handles.
    Thank to your insight we can add now less loading time, which sounds boring but feels so good when playing the game.
     
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  18. Scott Guo

    Scott Guo
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    Thank you very much @tdev, this post has been really informative and insightful. It's really interesting to see how you and your team approach the optimization of this specific task.
    --- Post updated ---
    BTW, I am wondering why not use streaming for IO (not quite sure whether Lua supports it).
     
  19. shortlildyl

    shortlildyl
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    when i try to load up a map it says somthing delivery carsh anyone know what to do?
     
  20. ast5515

    ast5515
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    Try safe mode. If it works, it's caused by a mod. Otherwise look at the known issues and fixes thread.
     
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