Intent to Ship: WebGPU: Transient attachments

[Chromestatus]

Contact emails

fbea...@google.com

Explainer

https://github.com/gpuweb/gpuweb/blob/main/proposals/transient-attachments.md

Specification

https://gpuweb.github.io/gpuweb/#dom-gputextureusage-transient_attachment

Summary

Functionality added to the WebGPU spec after its first shipment in a browser. A new TRANSIENT_ATTACHMENT GPUTextureUsage lets developers create attachments that allow render pass operations to stay in tile memory, avoiding VRAM traffic and potentially avoiding VRAM allocation for the textures.

Blink component

Blink>WebGPU

Web Feature ID

webgpu

Motivation

When a texture is declared transient (or "memoryless"), the GPU knows that the contents of that texture are only needed temporarily—specifically, only within the current render pass. Moreover, since the texture contents are discarded after the render pass, the driver may not even need to allocate space for that texture in the main VRAM at all. Even without hardware support for transient attachments, the hint can be used to reuse the allocation of transient textures between passes, which reduces peak memory usage. https://github.com/gpuweb/gpuweb/pull/5450

Initial public proposal

No information provided

TAG review

No information provided

TAG review status

Not applicable

Risks

Interoperability and Compatibility

This feature has not yet been implemented yet in any browser. It has been approved by the GPU for the Web Community Group, with representatives from Chrome, Firefox, and Safari. See minutes at https://github.com/gpuweb/gpuweb/wiki/GPU-Web-2025%E2%80%9011%E2%80%9005#add-support-for-memoryless-textures-5396

Gecko: No signal (https://github.com/mozilla/standards-positions/issues/1205#issuecomment-3312534193) wgpu used by Firefox already has transient attachments support. See https://github.com/gfx-rs/wgpu/pull/8247

WebKit: Closed Without a Position (https://github.com/WebKit/standards-positions/issues/294#issuecomment-1877411933) Apple representative approved the spec PR at https://github.com/gpuweb/gpuweb/pull/5450#pullrequestreview-3574410798

Web developers: No signals

Other signals:

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

No information provided

Debuggability

No information provided

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?

Yes

Is this feature fully tested by web-platform-tests?

Yes
WebGPU/WGSL have a conformance test suite (https://github.com/gpuweb/cts) that is regularly pulled into Chromium and part of the testing of Dawn/Tint in Chromium. While the CTS can be embedded in WPT, the WebGPU team opted to keep it separate in Chromium testing to use a customized harness for robustness and performance. All the tests about this feature in WebGPU CTS can be found at https://github.com/gpuweb/cts/issues/4509

Flag name on about://flags

Enable Unsafe WebGPU

Finch feature name

WebGPUTransientAttachment

Rollout plan

Will ship enabled for all users

Requires code in //chrome?

False

Tracking bug

https://issues.chromium.org/issues/462620664

Estimated milestones

DevTrial on desktop	146
DevTrial on Android	146

Anticipated spec changes

Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way).

No information provided

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5562829589577728?gate=6588224644448256

This intent message was generated by Chrome Platform Status.

[Yoav Weiss (@Shopify)]

LGTM1

Thanks for the explainer! This seems like a useful addition.

[Chris Harrelson]

LGTM2

--
You received this message because you are subscribed to the Google Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+...@chromium.org.
To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/ac3c79de-169c-47b8-8632-b787797a1a7an%40chromium.org.