Zed for Windows: What's Taking So Long?

Yeah, I maintain a Vulkan backend, and this immediately triggered my internal "what?" alarm.

Modern Direct3D is almost indistinguishable from Vulkan, on the other hand. So it shouldn't be difficult for them to add.

I also agree with your HLSL comment. It sounds like these guys don’t have much prior graphics or game development experience.

The Zed spirit is definitely to prefer a platform native solution.

You're right that we may be able to get rid of our WGSL implementation, and instead use the HLSL one via SPIR-V. But also, at some point we plan to port Zed to run in a web browser, and will likely build on WebGPU, where WGSL is the native shading language. Honestly, we don't change our graphics primitives that frequently, so the cost of having the three implementations going forward isn't that terrible. We definitely would not use MoltenVK on macOS, vs just using Metal directly.

Good point that we should publish a symbol server.

> I wonder why HLSL wasn't adopted from the outset

I suspect because a huge amount of software engineers develop on Macbooks and consider Linux second and Windows third. Culturally, I think there's a difference in tooling between Graphics developers (who would go straight for HLSL, cross-platform Vulkan, or even SDL3) and mac users (who reach for Apple tools first)

> Vulkan runs on Windows, and quite well.

Not everywhere. See the middle bug report, "Zed does not work in Remote Desktop session on windows" (https://github.com/zed-industries/zed/issues/26692).

Most Remote Desktop/Terminal Services environments won't have any Vulkan devices available, unless you ship your own software rendererer (like SwiftShader).

Also, NVIDIA only supports Vulkan on Kepler (GTX 600 series), AMD on GCN 1.0 (Radeon HD 7000 series), and most importantly, Intel on Skylake (6000 series). Especially on the Intel side, there are plenty of old but still-supported Windows 10 machines that lack Vulkan support. For many applications that's ok, but IMO not for a text editor.

Zed spirit is Mac first and only.

I have my macOS set up that all buttons have borders etc

If I switch no vanilla macOS, it’s basically unusable

Clean, but unusable

while I would agree in general, there could theoretically be SOME applications where the range of UI controls (and systems) is small enough where it could pay off. But things tend to expand in surface area...

So with that, this presents a HUGE opportunity for someone to build something akin to Zed, but not with the baggage that their technical strategy brings.

You'd rather see another crappy, slow editor packaging an entire browser? Because that seems like what people are using for "cross platform toolkits" these days. I'm glad Zed is being ambitious, it's truly a joy to use because it feels native. And to be honest, it's Windows, who cares. If you are a developer you should have switched to Linux years ago anyway.

The FOSS community has become full of ideological landmines, with projects now including clauses in their requirements, often vague and ill defined, about how those who build upon their projects must act and believe. As a result, some are now finding it less risky to roll their own base dependencies instead of using someone else's project that could at any time become problematic for non-technical reasons.

While I doubt this had anything to do with the decision by the Zed team to make their own toolkit, it is something becoming more common. Hopefully it doesn't start happening in the encryption space.

Or why you don't insist in using Khronos stuff on Windows, when most OEMs only care about the native API, DirectX.

Lets recap that this lesson has been learned by Godot developers, regarding their backends as well.

The ICD mechanism is a kind of escape hatch leftover due to backwards compatibility, and even user mode drivers build on top of DirectX runtime infrastructure.

What should they have used instead?

Think about the customer base: the sorts of users who want a high-performance text editor are exactly the kind of people who will run Windows 7 until it's pried from their cold, dead fingers, and who will flood the support forums with complaints if you limit support to operating systems released in the last 15 years. Because of their target market, Zed probably has implicit support requirements which wouldn't apply to e.g. the last first-person shooter.

DX12 isn't just "newer DX11" though, so it really comes down to what makes the most sense for building Zed with.

I've written a response below, but the summary is that mapping from Vulkan 1.3 with dynamic rendering to D3D11 is easier than targeting the lower-level D3D12. The latter does have some form of dynamic rendering too, but I suspect the authors woud've had to re-think their CPU code much more than what has currently been done. Getting Windows Vista and 7 support is a freebie.

Dx11 is a far more ergonomic API than dx12. Dx12 is what you use when you need maximum control over memory allocation and such

If you aren't trying to write a games engine, DX 11 is good enough, and won't be going away any time soon.

> but why does a code editor need to render on the GPU like a video game?

It isn't just text editors—nowadays, everything renders on your GPU, even your desktop and terminal (unless you're on a tty). For example, at the bottom of Chromium, Electron, and Avalonia's graphics stack is Skia, which is a cross-platform GPU-accelerated windowing and 2D graphics library.

GPU compositing is what allows transparency, glass effects, shadowing, and it makes actually writing these programs much easier, as everything is the same interface and uses the same rendering pipeline as everything else.

A window in front of another, or a window partially outside the display? No big deal, just set the 3D coordinates, width, and height correctly for each window, and the GPU will do hidden-surface removal and viewing frustum clipping automatically and for free, no need for any sorting. Want a 'preview' of the live contents of each window in a task bar or during Alt-Tab, like on Windows 7? No problem, render each window to a texture and sample it in the taskbar panels' smaller viewports. Want to scale or otherwise squeeze/manipulate the contents of each window during minimise/maximise, like macOS does? Easy, write a shader.

This was a big deal in the early 2000s when GPUs finally had enough raw compute to always run everything, and basically every single OS and compositor switched to GPU rendering roughly in the same timeline—Quartz Extreme on Mac OS X, DWM.exe on Windows, and Linux's variety of compositors, including KWin, Compiz, and more.

There's a reason OSs from that time frame had so many glassy, funky effects—this was primarily to show off just how advanced their GPU-powered compositors were, and this was also a big reason why Windows Vista fell so hard on its face—its compositor was especially hard on the scrawny integrated GPUs of the time, enough that two themes—Aero Basic, and Aero Glass—had to be released for different GPUs.

It doesn't need to. It's typical to do this these days, but they could still arrange all of the pixels on the CPU and then blit it onto the screen. There's an API to do so in every major OS.

Since it's more than quick enough to do this on the CPU, they're likely doing it for things like animations and very high quality font rendering. There's image-processing going on when you really care about quality; oversampling and filtering.

I suspect one could do most everything Zed does without a GPU, but about 10 to 20% uglier, depending on how discerning the user is on such things.

The zed blog has an early post[0] talking some about their decision. Mainly just decrying their experience of impossible-to-meet timing deadlines for something as basic as 60fps on electron.

It doesnt really do a tech breakdown of why it’d be impossible CPU side, but mentions a couple of things about their design process for it.

[0]: https://zed.dev/blog/videogame