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It's also notable that video games are programs that run for hours and iterate over large sets of very similar entities at 60 frames or more per second repeatedly and often do very similar operations on each of the entities.

That also means that "just do an array of flat records" is a very sane default even if it seems brutish at first.

by quietbritishjim2 hours ago|

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I think when he said "just do an array of flat records" he meant as opposed to record of arrays (i.e. row oriented vs column oriented), as opposed to fancy data structures which I think you're assuming he was implying. Separate arrays for each data member are common in game engines exactly because they're good for iterating over, which as you said is common.

by O3marchnative2 hours ago|

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That's also great for letting the compiler unlock auto-vectorization opportunities without delving into the world of manual SIMD.

Even storing something simple such as an array of complex numbers as a structure of arrays (SoA) rather than an array of structures (AoS) can unlock a lot of optimizations. For example, less permutes/shuffles and more arithmetic instructions.

Depending on how many fields you actually need when you iterate over the data, you prevent cache pollution as well.

by MaxBarraclough45 minutes ago|

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Jonathan Blow's own unreleased Jai programming language has a feature to make it trivial to switch between array-of-structs and struct-of-arrays.

From a quick search, it seems HackerNews's own jcelerier has put together a C++ library for doing this. https://github.com/celtera/ahsohtoa

by mabster46 minutes ago|

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I haven't watched his videos on his language for ages, but this was a big thing he wanted in his language: being able to swap between array-of-structs and struct-of-array quickly and easily.

by parasense17 minutes ago|

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The funny thing is even data structure is really an array of memory depending how low down deep one looks. All the people who took an intro computer science course knows, those who had to implement a heap allocator, it's all really just arrays underneath...

by Insanity6 hours ago|

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It's easy to see this outside of the perspective of a solo game developer. We all have deadlines to manage even in the regular 'corporate world'. And engineering time spent on a problem also translates to an actual cost.

It's a good consideration tbh.

by gowld31 minutes ago|

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Jonathan blow has spent the past 10 years and almost all of his money trying to build the perfect programming language for his 3rd game.

Also, Rule 5 contradicts the idea you quoted from Blow.

by skeeter20205 hours ago|

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I'd be careful extending learnings from games (solo or team efforts) to general programming as the needs and intent seem to be so different. We rarely see much code re-use in games outside of core, special-purpose buy largely isolated components and assets. Outside of games there's a much bigger emphasis on the data IME, and performance is often a nice-to-have.

by mabster35 minutes ago|

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It's been mixed moving to normal code: I haven't had to low-level optimise for ages now (man I miss that). But performance in the O() sense has been the same.

Game engine development is very much about processing of data. The pipeline is long and the tree is wide. Being able to reason about complicated data processing topologies mapped very easily across.

by awesome_dude3 hours ago|

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Yeah - A game is (generally) a one and done enterprise. Like a start up it's all about getting it out the door, there's little to no expectation of having to maintain it for any real length of time.

by fidotron1 hours ago|

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HN has some hot takes but that one is particularly impressive.

Fortnite, Roblox, League of Legends, Counter Strike . . . all very short term projects.

by wat100001 hours ago|

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For every game like that, there are a thousand games that shipped, maybe got a few updates, and then they were done.

by awesome_dude11 minutes ago|

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We can probably add to that the fact that the nominated titles almost certainly started out with spaghetti code that had to be refactored, reworked, and gave maintainers nightmares in their sleep

by awesome_dude59 minutes ago|

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[dead]

by suzzer993 hours ago|

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> how his initial implementation for virtually everything in Braid used arrays of records

This is me with hash maps.

by Fraterkes3 hours ago|

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