Comment by Flux159 | Hacker News Reader

Comment by Flux159 | Hacker News Reader

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Followup comment about Apple disallowing JIT - will need to confirm if JSC is allowed to JIT or only inside of a webview. I was able to get JSC + wgpu-native rendering in an iOS build, but would need to confirm if it can pass app review.

There's 2 other performance things that you can do by controlling the runtime though - add special perf methods (which I did for draco decoding - there is currently one __mystralNativeDecodeDracoAsync API that is non standard), but the docs clearly lay out that you should feature gate it if you're going to use it so you don't break web builds: https://mystralengine.github.io/mystralnative/docs/api/nativ...

The other thing is more experimental - writing an AOT compiler for a subset of Typescript to convert it into C++ then just compile your code ("MystralScript") - this would be similar to Unity's C# AOT compiler and kinda be it's own separate project, but there is some prior work with porffor, AssemblyScript, and Static Hermes here, so it's not completely just a research project.

Is AssemblyScript good for games though? last I checked it lacks too much features for game-code coming directly from TS but might be better now? No idea how well static hermes behaves today (but probably far better due to RN heritage).

I've been down the TS->C++ road a few times myself and the big issue often comes up with how "strict" you can keep your TS code for real-life games as well as how slow/messy the official TS compiler has been (and real-life taking time from efforts).

It's better now, but I think one should probably directly target the GO port of the TS compiler (both for performance and go being a slightly stricter language probably better suited for compilers).

I guess, the point is that the TS->C++ compilation thing is potentially a rabbit-hole, theoretically not too bad, but TS has moved quickly and been hard to keep up with without using the official compiler, and even then a "game-oriented" typescript mode wants to have a slightly different semantic model from the official one so you need either a mapping over the regular type-inference engine, a separate on or a parallell one.

Mapping regular TS to "game-variants", the biggest issue is how to handle numbers efficiently, even if you go full-double there is a need to have conversion-point checking everywhere doubles go into unions with any other type (meaning you need boxing or a "fatter" union struct). And that's not even accounting for any vector-type accelerations.

AssemblyScript was just mentioned as some prior work, I don't think that AssemblyScript would work as is for games.

I realize the major issues with TS->C++ though (or any language to C++, Facebook has prior work converting php to C++ https://en.wikipedia.org/wiki/HipHop_for_PHP that was eventually deprecated in favor of HHVM). I think that iteratively improving the JS engine (Mystral.js the one that is not open source yet but is why MystralNative exists) to work with the compiler would be the first step and ensuring that games and examples built on top with a subset of TS is a starting point here. I don't think that the goal for MystralScript should be to support Three.js or any other engine to begin with as that would end up going down the same compatibility pits that hiphop did.

Being able to update the entire stack here is actually very useful - in theory parts of mystral.js could just be embedded into mystralnative (separate build flags, probably not a standard build) avoiding any TS->C++ compilation for core engine work & then ensuring that games built on top are using the strict subset of TS that does work well with the AOT compilation system. One option for numbers is actually using comment annotations (similar to how JSDoc types work for typescript compiler, specifically using annotations in comments to make sure that the web builds don't change).

Re: TS compiler - I do have some basics started here and I am already seeing that tests are pretty slow. I don't think that the tsgo compiler has a similar API though for parsing & emitters right now, so as much as I would like to switch to it (I have for my web projects & the speed is awesome), I don't think I can yet until the API work is clarified: https://github.com/microsoft/typescript-go/discussions/455

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