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0 pointsvirtue311y ago0 comments

C# has very defined behaviour that when "ported" to C++ is going to result in similar speed hits. Allocations are zero'd out. boxing/unboxing objects, array bounds checking.

GC is going to be the big hit as you're still going to need to pay for that even in C++ land. I'm not really seeing what you'd get over just C# with a more modern JIT unless you start converting to non-safe C code and doing sneaky c stuff behind the scenes (and I'm sure absolutely nothing will go wrong*).

The webgl stuff is fine to not be bound (I'm assuming it's being converted to js anyway?) but anything running in the plugin better be.

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azakai11y ago

First and foremost, compiling to C++ means you then optimize it using a full C++ compiler like gcc or clang+LLVM. Not only are those compilers generally better than JITs, they can also do whole-program optimizations. JITs are getting that too (Dalvik=>ART, newer .NET runtimes), but the C and C++ compilers have a big head start.

(In theory a JIT can do all the things C++ compilers do, of course.)

Aside from performance, Mono must be ported to each target platform (I've heard this can take significant effort). On the other hand, well-written C++ code should just run (the rest of the engine is in C++ anyhow).

edit: yes, Unity compiles C# to C++, then to JS to run in the browser.

Skinney11y ago

All true, but you're forgetting that Mono can AOT compile C# to native code using LLVM. That's how Xamarin.iOS works. So il2cpp doesn't really bring anything new to the table.

pdaddyo11y ago

But it does solve their biggest issue - ultimately enabling Unity projects to publish to the web without plugins (WebGL / javascript).

Once all code in a Unity project eventually ends up as C++ (even if it started as C#), they can leverage Emscripten, asm.js and related technologies to enable Unity devs to use C# in the editor, which is converted to C++, and ultimately Javascript. It seems crazy, but it might just work!

cwyers11y ago

"But it does solve their biggest issue - ultimately enabling Unity projects to publish to the web without plugins (WebGL / javascript)."

I'm not really sure that is their biggest issue; HTML5 publishing of Unity games seems mostly a novelty at this point.

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Skinney11y ago

Regarding the C# -> C++ -> JS thing, it really must alot easier to do a C# -> JS conversion...

j / k navigate · click thread line to collapse

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azakai11y ago

(In theory a JIT can do all the things C++ compilers do, of course.)

edit: yes, Unity compiles C# to C++, then to JS to run in the browser.

Skinney11y ago

All true, but you're forgetting that Mono can AOT compile C# to native code using LLVM. That's how Xamarin.iOS works. So il2cpp doesn't really bring anything new to the table.

pdaddyo11y ago

But it does solve their biggest issue - ultimately enabling Unity projects to publish to the web without plugins (WebGL / javascript).

cwyers11y ago

"But it does solve their biggest issue - ultimately enabling Unity projects to publish to the web without plugins (WebGL / javascript)."

I'm not really sure that is their biggest issue; HTML5 publishing of Unity games seems mostly a novelty at this point.

1 more reply

Skinney11y ago

Regarding the C# -> C++ -> JS thing, it really must alot easier to do a C# -> JS conversion...

j / k navigate · click thread line to collapse