design VS mach

First of all, a quick rundown of what WASM is. It stands for Web Assembly. In essence, similar to how Java compiles down to a bytecode that is interpreted by a Java Virtual Machine, Web Assembly is a different bytecode interpreted by the browser. Many different languages can compile into WASM, and Javascript can interface with it like a module. In my case, I wrote a lot of the source code in Rust and compiled it down to a WASM module, then called into it from Javascript.

WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable compilation target for programming languages, enabling deployment on the web for client and server applications. - https://webassembly.org

With WebAssembly we can compile our C++ codebase into a wasm module for the browser. So when you look at a SciChart.js chart you're actually seeing our C++ graphics engine wrapped for JavaScript.

I should add, however, that the unmentioned elephant in the room is V8 JIT (TurboFan), which simply doesn't handle irreducible control flow. While there are some valid theoretical arguments around the current arrangement in Wasm, looking at the history of the associated discussions makes it pretty obvious that having V8 support Wasm and generate fast code similar to what it can do for asm.js was an overriding concern in many cases. And Google straight up said that if Wasm has ICF, they will not bother supporting such cases, so it will be done by a much slower fallback:

https://github.com/WebAssembly/design/issues/796#issuecommen...

AFAIK no other Wasm implementation has the same constraint - the rest generally tend to desugar everything to jumps and then proceed from there. So this is, at least to some extent, yet another case of a large company effectively forcing an open standard to be more convenient for them specifically.

https://github.com/WebAssembly/design/issues/1397

> Currently allocating more than ~300MB of memory is not reliable on Chrome on Android without resorting to Chrome-specific workarounds, nor in Safari on iOS.

That's about allocating CPU memory but the GPU memory situation is similar.

As far as I can tell (5 minutes of internet research) this was to allow easier compilation to JavaScript as a fallback in the days when WASM wasn't widely supported.

"Please add goto" issue has been open since 2016:

https://github.com/WebAssembly/design/issues/796

Most interesting comment:

> The upcoming Go 1.11 release will have experimental support for WebAssembly. This will include full support for all of Go's features, including goroutines, channels, etc. However, the performance of the generated WebAssembly is currently not that good.

> This is mainly because of the missing goto instruction. Without the goto instruction we had to resort to using a toplevel loop and jump table in every function. Using the relooper algorithm is not an option for us, because when switching between goroutines we need to be able to resume execution at different points of a function. The relooper can not help with this, only a goto instruction can.

> It is awesome that WebAssembly got to the point where it can support a language like Go. But to be truly the assembly of the web, WebAssembly should be equally powerful as other assembly languages. Go has an advanced compiler which is able to emit very efficient assembly for a number of other platforms. This is why I would like to argue that it is mainly a limitation of WebAssembly and not of the Go compiler that it is not possible to also use this compiler to emit efficient assembly for the web.

^ https://github.com/WebAssembly/design/issues/796#issuecommen...

When I implemented a WASM compiler, the only source of float-based non-determinism I found was in the exact byte representation of NaN. Floating point math is deterministic. See https://webassembly.org/docs/faq/#why-is-there-no-fast-math-... and https://github.com/WebAssembly/design/blob/main/Nondetermini....

> To work with GC, you need some way to track if the GC'd object is accessible in WASM itself.

I've never heard of a GC with that kind of API. Usually any native code that holds a GC reference would either mark that reference as a root explicitly (eg. https://github.com/WebAssembly/design/issues/1459) or ensure that it can be traced from a parent object. Either way, this should prevent collection of the object. I agree that explicitly checking whether a GC'd object has been freed would not make any sense.

> The reason why you probably need a custom string type is so you can actually embed string literals without relying on interop with the environment.

WASM already has ways of embedding flat string data. This can be materialized into GC/heap objects at module startup. This must happen in some form anyway, as all GC-able objects must be registered with the GC upon creation, for them to be discoverable as candidates for collection.

Overall I still don't understand the issue. There is so much prior art for these patterns in native extensions for Python, PHP, Ruby, etc.

Giving you a buffer that grows is the allocation approach I am talking about. This is not how your OS works. Your OS itself works with an allocator that does a pretty good job making sure that your memory ends up not fragmented. Because WASM is in between, the OS is not in control of the memory, and instead the browser is. The browser implementation of "bring your own allocator" is cute but realistically just a waste of time for everybody who wants to deploy a wasm app because whatever allocator you bring is crippled by the overarching allocator of the browser messing everything up.

It seems like the vendors are recognizing this though, with firefox now having a discard function aparently!

https://github.com/WebAssembly/design/issues/1397

Myself and many others are betting on Zig in major ways, I truly think it has a bright future ahead.

In spare time, myself and a few others are working on a game engine in Zig[0], and the Zig core team has been very receptive to addressing issues our project faces and supporting us.

Others are working on pixel art editors[1], open source 2D RPG games[2], there's a group of independent folks working on a 3D massive immersive sim game[3], a group working on making Zig an amazing language for micro-controllers[4], etc.

Please consider donating $5-10 a month to the ZSF! They are a great group of people, and it has so many knock-on effects for others in the FOSS community. :)

[0] https://machengine.org/

[1] https://github.com/foxnne/pixi

[2] https://github.com/foxnne/aftersun

[3] https://github.com/Srekel/tides-of-revival

[4] https://github.com/ZigEmbeddedGroup

I don't know if there's anything better than a zip. For our website[0] which includes a bunch of docs for our game engine, Zig packages, etc. we just offer a link "offline version of this site" in the footer which is an ~80MB zip file.

I think the challenge with zip files is.. do you want all the images? do you want all versions of the docs, or just a specific version of the docs? It's hard to tailor the zip to the user's desire. But zip still seems to be the best.

[0] https://machengine.org/

Cool to see others working on this problem. I hope more people do.

Funnily I've seen a lot of programmers and math folks who express how truly, genuinely beautiful Beziers and the math behind them are. But I've never met an artist or graphic designer who didn't express some deep frustration at Bezier controls and how hard they are to work with.

There are even games[0] which make a mockery out of how hard Bezier controls are to use, where the game is purely using the controls.

Controls are just one side of the problem, in my view; the other side is that cubics are terrible for GPUs, they don't understand them - and I believe many of the best 2D graphics libraries today are not even fully GPU accelerated, e.g. Skia. There are folks working on compute shader-based approaches, where we try to shoe-horn this CPU-focused algorithm into GPUs and pray - but it still isn't really suitable.

The controls suck for artists, and the math sucks for GPUs. This is only true of cubics, if you restrict yourself to quadratics (although that brings other challenges), both the control issue goes away (you can just click+drag the curve!) and the performance issue goes away (quadratics are triangles, GPUs love them)

That's the summary of the talk[1] I gave at SYCL'22. In that talk, I didn't have time to present the downsides of quadratics (which are real) - so if you watch it please keep that in mind - but my overall point I think is a solid one: the controls suck, and GPUs can't handle them.

The only reason we stick with cubics in its current form is because of SVG, compatibility with existing tooling, etc. But isn't it crazy? We have new bitmap image formats all the time, and so few vector graphics formats.

In Mach engine[2] we're continuing to explore this space, end-to-end, from author tooling -> format -> rendering. I'm not claiming we have a perfect solution, we don't, but we're at least thinking about this problem. Kudos to the authors of this article for thinking about this space as well.

[0] https://bezier.method.ac/

[1] https://www.youtube.com/watch?v=QTybQ-5MlrE

[2] https://machengine.org

A game engine https://machengine.org is being written in zig, there's also https://microzig.tech as zig is well suited to embedded development.

https://github.com/hexops/mach (shameless plug)

Zig fits pretty naturally here too. We've got ~19 WebGPU examples[1] which use Dawn natively (no browser support yet), and we build it using Zig's build system so it 'just works' out of the box with zero fuss as long as you grab a recent Zig version[2]. No messing with cmake/ninja/depot_tools/etc.

WASM support in Zig, Rust, and C++ is also not equal. C++ prefers Emscripten which reimplements parts of popular libraries like SDL, for me personally that feels a bit weird as I don't want my compiler implementing my libraries / changing how they behave. Rust I believe generally avoids emscripten(?), but Zig for sure lets me target WASM natively and compile C/C++ code to it using the LLVM backend and soon the custom Zig compiler backend.

[1] https://github.com/hexops/mach-examples

[2] https://github.com/hexops/mach#supported-zig-version

We're building Mach which aims to be competitive with Unity/Unreal/Godot in spriti, but super modular / let you pick and choose which parts to use or build yourself.

git clone --recursive https://github.com/hexops/mach-examples cd mach-examples/ zig build run-sprite2d