3 ms·

DOTS is in fact a major step up. It can't be done in engine code the same way you can't handle say oop to functional programming conversion in engine code.

mpartel 6y ago
I'm not so sure that would have been impossible. Nothing fundamental seems to prevent the compiler+runtime from: - laying out instances of the same Component next to each other in memory - Burst.Compiling their Update() functions - adding backwards compatible APIs to do parallel loops etc over multiple components Given the culture of constant rewrites Unity has displayed (and I'm sure they have lots of techdebt to make rewrites feel appealing), its seems far from certain that they explored avenues like this sufficiently. Or maybe they felt their earlier modification of Mono, which kept them on an old version of .NET for so long, was too painful to even consider touching the runtime ever again.
- Mirioron 6y ago
  >Nothing fundamental seems to prevent the compiler+runtime from: - laying out instances of the same Component next to each other in memory - Burst.Compiling their Update() functions - adding backwards compatible APIs to do parallel loops etc over multiple components And if those Update functions reference other objects and do something with them? If the engine automatically realigns the order in which Update is called on objects then you can't do something like that, you'd run into weird behavior. Or do I somehow misunderstand? From what I understand, the whole point of DOTS is to get people to write code that uncouples the data from what operates on the data. Once they have that they can shuffle these calls around.
  - mpartel 6y ago
    Of course you'd still have restrictions on the code if you want it magically optimized, just as with DOTS. But you're right to be skeptical, this is not something I've thought through that thoroughly :)
    - adamnemecek 6y ago
      The point of ECS is that your mental model is very close to the GPU. Some sort of rewriting process would just add additional costs to this.
wokwokwok 6y ago
what are you talking about? DOTS is even more of a dumpster fire than the URP/HDRP. They have an unstable base layer that is constantly changing (eg. SystemBase and for each is literally what, two months old and the old stuff is depreciated now?), a version control system for packages that doesn’t work at all (see all the threads on why don’t my packages work?). ...and guess what? They’re using that as a base to build the physics, audio, networking, animation and visual scripting on. No wonder its taking forever... those poor other teams are royally screwed, because every time they make any progress, the DOTS guys go and re do everything from scratch. codegen? nah. we’re giving up on that too now, it was too hard. ...I mean, the demos are great and all, but DOTS is a mess. Its not a “step up”, its a vague pie in the sky idea, and a bunch of people making a big old mess. Its not even part of the 2020 roadmap.
haydenlee 6y ago
Yet the support for it still sucks. I spent a few hours trying to set it up the other day and still couldn't get it working. (Unity developer of 6 years here). Maybe I just had one setting wrong.. but this shouldn't be that hard to anybody, and as rightly Garry points out its not necessarily a lack of documentation but the fact that the documentation is so out of date OR correct but only with one unique combination of versions from 2 years ago.

mpartel 6y ago

I'm not so sure that would have been impossible. Nothing fundamental seems to prevent the compiler+runtime from: - laying out instances of the same Component next to each other in memory - Burst.Compiling their Update() functions - adding backwards compatible APIs to do parallel loops etc over multiple components Given the culture of constant rewrites Unity has displayed (and I'm sure they have lots of techdebt to make rewrites feel appealing), its seems far from certain that they explored avenues like this sufficiently. Or maybe they felt their earlier modification of Mono, which kept them on an old version of .NET for so long, was too painful to even consider touching the runtime ever again.

Mirioron 6y ago
>Nothing fundamental seems to prevent the compiler+runtime from: - laying out instances of the same Component next to each other in memory - Burst.Compiling their Update() functions - adding backwards compatible APIs to do parallel loops etc over multiple components And if those Update functions reference other objects and do something with them? If the engine automatically realigns the order in which Update is called on objects then you can't do something like that, you'd run into weird behavior. Or do I somehow misunderstand? From what I understand, the whole point of DOTS is to get people to write code that uncouples the data from what operates on the data. Once they have that they can shuffle these calls around.
- mpartel 6y ago
  Of course you'd still have restrictions on the code if you want it magically optimized, just as with DOTS. But you're right to be skeptical, this is not something I've thought through that thoroughly :)
  - adamnemecek 6y ago
    The point of ECS is that your mental model is very close to the GPU. Some sort of rewriting process would just add additional costs to this.

wokwokwok 6y ago

what are you talking about? DOTS is even more of a dumpster fire than the URP/HDRP. They have an unstable base layer that is constantly changing (eg. SystemBase and for each is literally what, two months old and the old stuff is depreciated now?), a version control system for packages that doesn’t work at all (see all the threads on why don’t my packages work?). ...and guess what? They’re using that as a base to build the physics, audio, networking, animation and visual scripting on. No wonder its taking forever... those poor other teams are royally screwed, because every time they make any progress, the DOTS guys go and re do everything from scratch. codegen? nah. we’re giving up on that too now, it was too hard. ...I mean, the demos are great and all, but DOTS is a mess. Its not a “step up”, its a vague pie in the sky idea, and a bunch of people making a big old mess. Its not even part of the 2020 roadmap.

haydenlee 6y ago

Yet the support for it still sucks. I spent a few hours trying to set it up the other day and still couldn't get it working. (Unity developer of 6 years here). Maybe I just had one setting wrong.. but this shouldn't be that hard to anybody, and as rightly Garry points out its not necessarily a lack of documentation but the fact that the documentation is so out of date OR correct but only with one unique combination of versions from 2 years ago.