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Likewise the focus on ECS architecture as being the one true DoD pattern when it’s not necessarily data oriented at all and the unfounded assumption it’s used e

Likewise the focus on ECS architecture as being the one true DoD pattern when it’s not necessarily data oriented at all and the unfounded assumption it’s used everywhere in game development when it isn’t . And somehow the idea that DoD is a replacement for OOP when it’s really an orthogonal concern. DoD is about recognising data use patterns in your software and organising your software architecture around them in a way that suits the constraints of modern hardware. That’s all.

bfrydl 6y ago
I think this is because of Rust. In my opinion the Rust game dev community is overly fixated on ECS. On the bright side, Rust has some damn good ECS libraries.
- meheleventyone 6y ago
  I’d agree to a point but it really crosses the whole gamut of hobby game engine development. It’s weirdly self reinforcing even in the face of more interesting architectural choices like DOOM Eternal’s.
  - carteloupe 6y ago
    Interested what the architecture of DOOM Eternal is like, was there some talk / blog post about it?
    - meheleventyone 6y ago
      I believe it’s only been mentioned in passing and likely will be talked about at conferences soonish. Here’s a HN thread from when it was first talked about: https://news.ycombinator.com/item?id=22700563 https://news.ycombinator.com/item?id=22700563 There was an early talk about using a job system to run the Destiny renderer and then this one for the whole engine which is a very similar premise to the way DOOM(2016) and then DOOM Eternal evolved. https://www.gdcvault.com/play/1022164/Multithreading-the-Entire-Destiny https://www.gdcvault.com/play/1022164/Multithreading-the-Ent... The renderer talk is here: https://youtu.be/0nTDFLMLX9k https://youtu.be/0nTDFLMLX9k
  - runevault 6y ago
    The way Eternal's engine is described it could simply be an ECS with a more advanced job system for farming out work because it can parse how the various objects are updated and only do reads after all writes to the objects happen.
- swsieber 6y ago
  Rust lends itself to ECS a lot more than it lends itself to behavior hierarchies using inheritance. That's an over simplification, but a useful one.
  - bfrydl 6y ago
    I agree that Rust is more suited to ECS than hierarchies. However, the choice is not between ECS or inheritance. The reason I say that the community is overly fixated on it is that many of the benefits attributed to ECS aren't unique to ECS.
- munificent 6y ago
  > the Rust game dev community is overly fixated on ECS. Not just Rust. The game dev community everywhere is infatuated with ECS. It's basically cargo culting. There is a large base of amateur or indie game developers who want to feel like they are doing game development the "right" way. One big aspect of that is performance. ECS has a reputation for efficiency (which is true, when used well in a context where your performance problems are related to caching), so you see a lot of game devs slavishly applying it to their code in hopes that the "go as fast as a AAA game" Gods will land on their runway and deliver the goods. Every time I see a new ECS framework in JavaScript, I die a little on the inside.
  - barrkel 6y ago
    I wouldn't dismiss the JS ECS frameworks without measurement. Polymorphism has costs, and while dynamic languages work hard to remove them, they still work best when they're able to monomorphize the call site, because that enables inlining without combinatoric explosion from chained polymorphic calls. Having a single type in your array means field accesses, method calls etc. have the potential to be monomorphized. There are performance wins to laying out your data in ways that avoid the need for polymorphism.
    - meheleventyone 6y ago
      I don’t believe any JS engines do any “shape” or “hidden class” caching other than for call site polymorphism?
    - munificent 6y ago
      > I wouldn't dismiss the JS ECS frameworks without measurement. I think the burden of proof is on the part of JS ECS frameworks to show they do have better performance by virtue of DoD and, if so, why. JS engine programmers have been optimizing object-oriented code for literally forty years, all the way back to when they were making Smalltalk VMs. If somehow a couple of folks hacking on ECS frameworks have managed to write code that runs faster on those JS engines than the kind of code they were designed for, I'd like to see it. > Having a single type in your array means field accesses, method calls etc. have the potential to be monomorphized. Sure, but object-oriented code does not require any more polymorphism than DoD does. Consider: * Iterate over an array of monomorphic components and call a method on each one. * Iterate over an array of monomorphic entities, access a monomorphic property, and call a method on the latter. There's an extra property access in the latter (which can easily be inlined), but no polymorphic dispatch. In practice, yes, it is possible to reorganize your JavaScript code in ways that play nicer with inline and possibly even code caching. But I have never seen any evidence that JS ECS frameworks actually do that. Instead, the few I've poked around in seem like typical slow imperative dynamically-typed JS. If someone is going to take a pattern that was invented specifically for a language like C++ that gives you precise control over memory layout and then apply it to a language that not doesn't give you that control but often uses hash tables to store an object's state, I think the burden of proof is on the framework to show that the pattern actually applies.
throwaway894345 6y ago
> And somehow the idea that DoD is a replacement for OOP when it’s really an orthogonal concern. I’m sure this is true for some definition of OOP, but I’ve seen too much OOP code that insists on hanging every method off of the most plain-old-data of classes. A Book class has to have a buyFromAmazon() method and consequently each instance has a private reference to an Amazon SDK client, and if you want to buy 10K books, you iterate over a list and invoke this method 10K times. Of course, some will argue that this is bad OOP and true OOP doesn’t look like this, and anyway you can write bad code in any paradigm! Of course, OOP is uniquely plagued with bad code (much more so than other paradigms) and this pretty transparent no-True-Scotsman argument is just moving semantic goalposts (as such arguments do).
- meheleventyone 6y ago
  Whilst it’s impressive you’ve managed to hold an argument with yourself I think it’s more the case that anything as broad as a programming paradigm will naturally hold multiple approaches. Is immutability a defining feature of FP? Let the battles commence. Likewise critics might focus heavily on inheritance or some other feature of OOP that is easy to critique. And whilst I’m not particularly interested in defending OOP I think describing it as uniquely plagued with bad code is not something anyone should just take axiomatically.
  - throwaway894345 6y ago
    > Whilst it’s impressive you’ve managed to hold an argument with yourself I like to address the boringly predictable responses up front so we can avoid rehashing the same silly arguments over and over. I apologize if that spoiled your fun. > Is immutability a defining feature of FP? Let the battles commence. I think most would agree that immutability is more prevalent in FP even if struct immutability isn’t required. Moreover, everyone would agree that first class functions and functional composition are key characteristics. Contrast that with OOP where you have some OOP enthusiasts arguing that inheritance is a defining feature and others who argue it isn’t. Some argue that the “kingdom of nouns”, banana-gorilla-jungle design is inherently OOP and others argue it’s “bad programming and not true OOP”. Others argue that message passing is required, but many others argue to the contrary. While other programming paradigms have fuzzy edges, OOP has no discernible shape at all. > And whilst I’m not particularly interested in defending OOP I think describing it as uniquely plagued with bad code is not something anyone should just take axiomatically. Why are there no equivalent criticisms of FP or DO? We might find FP codebases that are overly abstract or a bit slow, but we don’t tend to find (m)any that are designed such that a Book object holds a reference to an Amazon SDK client or a banana with a reference to the gorilla holding it with a reference to the entire jungle. There aren’t prevalent guidance to write code like that in other communities like there is (or perhaps “was”) in OOP circles. Similarly, there aren’t enterprise-y abstract factory beans or anything like that in the FP world. Mind you, I’m not dumping on OOP—indeed I couldn’t if I wanted to because it has no agreed upon definition, per its proponents.
FullyFunctional 6y ago
It took me a fair amount of searching to establish that ESC refers to https://en.wikipedia.org/wiki/Entity_component_system https://en.wikipedia.org/wiki/Entity_component_system
- kbenson 6y ago
  That's okay, now that you're familiar with the term, you'll end up noticing it a lot more (or maybe it's just that articles that happen to lend themselves to it showing up in their comments look slightly more appealing now?).
- pjmlp 6y ago
  Basically it boils down to making use of Objective-C protocols or multiple inheritance, with data separated from behavior in regards to implementation. So a 1986 concept rediscovered by game developers and cargo culted ever since, although it has its roots on the OOP they love to hate.

bfrydl 6y ago

I think this is because of Rust. In my opinion the Rust game dev community is overly fixated on ECS. On the bright side, Rust has some damn good ECS libraries.

meheleventyone 6y ago
I’d agree to a point but it really crosses the whole gamut of hobby game engine development. It’s weirdly self reinforcing even in the face of more interesting architectural choices like DOOM Eternal’s.
- carteloupe 6y ago
  Interested what the architecture of DOOM Eternal is like, was there some talk / blog post about it?
  - meheleventyone 6y ago
    I believe it’s only been mentioned in passing and likely will be talked about at conferences soonish. Here’s a HN thread from when it was first talked about: https://news.ycombinator.com/item?id=22700563 https://news.ycombinator.com/item?id=22700563 There was an early talk about using a job system to run the Destiny renderer and then this one for the whole engine which is a very similar premise to the way DOOM(2016) and then DOOM Eternal evolved. https://www.gdcvault.com/play/1022164/Multithreading-the-Entire-Destiny https://www.gdcvault.com/play/1022164/Multithreading-the-Ent... The renderer talk is here: https://youtu.be/0nTDFLMLX9k https://youtu.be/0nTDFLMLX9k
- runevault 6y ago
  The way Eternal's engine is described it could simply be an ECS with a more advanced job system for farming out work because it can parse how the various objects are updated and only do reads after all writes to the objects happen.
swsieber 6y ago
Rust lends itself to ECS a lot more than it lends itself to behavior hierarchies using inheritance. That's an over simplification, but a useful one.
- bfrydl 6y ago
  I agree that Rust is more suited to ECS than hierarchies. However, the choice is not between ECS or inheritance. The reason I say that the community is overly fixated on it is that many of the benefits attributed to ECS aren't unique to ECS.
munificent 6y ago
> the Rust game dev community is overly fixated on ECS. Not just Rust. The game dev community everywhere is infatuated with ECS. It's basically cargo culting. There is a large base of amateur or indie game developers who want to feel like they are doing game development the "right" way. One big aspect of that is performance. ECS has a reputation for efficiency (which is true, when used well in a context where your performance problems are related to caching), so you see a lot of game devs slavishly applying it to their code in hopes that the "go as fast as a AAA game" Gods will land on their runway and deliver the goods. Every time I see a new ECS framework in JavaScript, I die a little on the inside.
- barrkel 6y ago
  I wouldn't dismiss the JS ECS frameworks without measurement. Polymorphism has costs, and while dynamic languages work hard to remove them, they still work best when they're able to monomorphize the call site, because that enables inlining without combinatoric explosion from chained polymorphic calls. Having a single type in your array means field accesses, method calls etc. have the potential to be monomorphized. There are performance wins to laying out your data in ways that avoid the need for polymorphism.
  - meheleventyone 6y ago
    I don’t believe any JS engines do any “shape” or “hidden class” caching other than for call site polymorphism?
  - munificent 6y ago
    > I wouldn't dismiss the JS ECS frameworks without measurement. I think the burden of proof is on the part of JS ECS frameworks to show they do have better performance by virtue of DoD and, if so, why. JS engine programmers have been optimizing object-oriented code for literally forty years, all the way back to when they were making Smalltalk VMs. If somehow a couple of folks hacking on ECS frameworks have managed to write code that runs faster on those JS engines than the kind of code they were designed for, I'd like to see it. > Having a single type in your array means field accesses, method calls etc. have the potential to be monomorphized. Sure, but object-oriented code does not require any more polymorphism than DoD does. Consider: * Iterate over an array of monomorphic components and call a method on each one. * Iterate over an array of monomorphic entities, access a monomorphic property, and call a method on the latter. There's an extra property access in the latter (which can easily be inlined), but no polymorphic dispatch. In practice, yes, it is possible to reorganize your JavaScript code in ways that play nicer with inline and possibly even code caching. But I have never seen any evidence that JS ECS frameworks actually do that. Instead, the few I've poked around in seem like typical slow imperative dynamically-typed JS. If someone is going to take a pattern that was invented specifically for a language like C++ that gives you precise control over memory layout and then apply it to a language that not doesn't give you that control but often uses hash tables to store an object's state, I think the burden of proof is on the framework to show that the pattern actually applies.

throwaway894345 6y ago

> And somehow the idea that DoD is a replacement for OOP when it’s really an orthogonal concern. I’m sure this is true for some definition of OOP, but I’ve seen too much OOP code that insists on hanging every method off of the most plain-old-data of classes. A Book class has to have a buyFromAmazon() method and consequently each instance has a private reference to an Amazon SDK client, and if you want to buy 10K books, you iterate over a list and invoke this method 10K times. Of course, some will argue that this is bad OOP and true OOP doesn’t look like this, and anyway you can write bad code in any paradigm! Of course, OOP is uniquely plagued with bad code (much more so than other paradigms) and this pretty transparent no-True-Scotsman argument is just moving semantic goalposts (as such arguments do).

meheleventyone 6y ago
Whilst it’s impressive you’ve managed to hold an argument with yourself I think it’s more the case that anything as broad as a programming paradigm will naturally hold multiple approaches. Is immutability a defining feature of FP? Let the battles commence. Likewise critics might focus heavily on inheritance or some other feature of OOP that is easy to critique. And whilst I’m not particularly interested in defending OOP I think describing it as uniquely plagued with bad code is not something anyone should just take axiomatically.
- throwaway894345 6y ago
  > Whilst it’s impressive you’ve managed to hold an argument with yourself I like to address the boringly predictable responses up front so we can avoid rehashing the same silly arguments over and over. I apologize if that spoiled your fun. > Is immutability a defining feature of FP? Let the battles commence. I think most would agree that immutability is more prevalent in FP even if struct immutability isn’t required. Moreover, everyone would agree that first class functions and functional composition are key characteristics. Contrast that with OOP where you have some OOP enthusiasts arguing that inheritance is a defining feature and others who argue it isn’t. Some argue that the “kingdom of nouns”, banana-gorilla-jungle design is inherently OOP and others argue it’s “bad programming and not true OOP”. Others argue that message passing is required, but many others argue to the contrary. While other programming paradigms have fuzzy edges, OOP has no discernible shape at all. > And whilst I’m not particularly interested in defending OOP I think describing it as uniquely plagued with bad code is not something anyone should just take axiomatically. Why are there no equivalent criticisms of FP or DO? We might find FP codebases that are overly abstract or a bit slow, but we don’t tend to find (m)any that are designed such that a Book object holds a reference to an Amazon SDK client or a banana with a reference to the gorilla holding it with a reference to the entire jungle. There aren’t prevalent guidance to write code like that in other communities like there is (or perhaps “was”) in OOP circles. Similarly, there aren’t enterprise-y abstract factory beans or anything like that in the FP world. Mind you, I’m not dumping on OOP—indeed I couldn’t if I wanted to because it has no agreed upon definition, per its proponents.

FullyFunctional 6y ago

It took me a fair amount of searching to establish that ESC refers to https://en.wikipedia.org/wiki/Entity_component_system https://en.wikipedia.org/wiki/Entity_component_system

kbenson 6y ago
That's okay, now that you're familiar with the term, you'll end up noticing it a lot more (or maybe it's just that articles that happen to lend themselves to it showing up in their comments look slightly more appealing now?).
pjmlp 6y ago
Basically it boils down to making use of Objective-C protocols or multiple inheritance, with data separated from behavior in regards to implementation. So a 1986 concept rediscovered by game developers and cargo culted ever since, although it has its roots on the OOP they love to hate.