Sandbox::https://github.com/mrdoob/three.js/pull/35028

AdaRoseCannon · 2026-10-15T17:57:19Z

Support WebXR DirectRenderPipeline on VisionOS by sizing the XR render target from the projection layer, using its logical viewport, and supplying single-sample foveated depth for reprojection

Description

VisionOS can't expose the dimensions of the projection layer before the first frame, so the XR render target is resized when the size is available

VisionOS requires the depth buffer for reprojection so when the depth buffer is not ignored the WebXR provided depth texture is used

On visionOS the sub-image viewport is the logical (pre-foveation) size, which is larger than the projection layer texture size so that is used for rendering

…et from the projection layer, using its logical viewport, and supplying single-sample foveated depth for reprojection

AdaRoseCannon · 2026-10-15T17:57:37Z

cc @cabanier (tested on quest and visionOS)

github-actions · 2026-10-15T18:00:10Z

📦 Bundle size

Full ESM build including core, minified and gzipped.

	Before	After	Diff
Core	391.30 102.65	391.30 102.65	+0 B +0 B
WebGL	777.73 194.24	777.73 194.24	+0 B +0 B
WebGPU	1099.90 296.20	1101.57 296.62	+1.66 kB +423 B
WebGPU Nodes	1097.85 295.84	1099.51 296.27	+1.66 kB +426 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	518.57 124.62	518.57 124.62	+0 B +0 B
WebGPU	778.14 208.33	779.77 208.74	+1.63 kB +405 B
WebGPU Nodes	725.26 195.14	726.89 195.54	+1.63 kB +402 B

cabanier

@AdaRoseCannon , your change disables MSAA in WebXR.
Are you planning on bringing it back in a follow up PR?

cabanier · 2026-10-15T18:36:48Z

 			viewDescriptors: [],
-			viewports: []
+			viewports: [],
+			depthTextures: [],


The spec says that the same texture needs to be returned for left and right eye. Treat the depth texture like colorTexture

cabanier · 2026-10-15T18:41:06Z

Should we pass depthStencilFormat here? The current WebXR WebGPU spec says omitting it means no depth texture is allocated. That leaves ignoreDepthValues true, so the new supplied-depth path depends on the browser implicitly allocating depth.

Alternatively, we can update the spec to leave it up to the user agent

I'd rather follow the spec at this point, so i'll fix it :)

if we put it here will Quest then supply a depth buffer? I think it will ignore this and it won't, right?

if you put it here, quest will create a depth buffer. Use usesDepthValues on the gpubinding. If it's true, ask for depth textures

cabanier · 2026-10-15T18:42:53Z

+			if ( supplyDepth === true && gpuSubImage.depthStencilTexture ) {
+
+				viewData.depthTextures.push( gpuSubImage.depthStencilTexture );
+				viewData.depthViewDescriptors.push( gpuSubImage.getViewDescriptor() );


getViewDescriptor() returns a descriptor usable for both color and depth. Can we reuse viewDescriptors and remove depthViewDescriptors and the second call?

cabanier · 2026-10-15T18:44:34Z

 		xrRenderTarget.dispose();

 		// The external texture can be registered before the render target is initialized.
 		for ( const texture of xrRenderTarget.textures ) {


Can we also clear the external depth wrapper’s backend record here?
Its registration bypasses Textures.updateTexture(), so normal texture cleanup does not remove it, and this loop only handles color textures. We should release the cached depth references without destroying the browser-owned GPU texture

cabanier · 2026-10-15T19:01:46Z

+			}
+
+			// The pass viewport comes from the render target viewport. Use the logical sub-image
+			// viewport: on visionOS it is larger than the foveated texture and the runtime maps it.


Could we describe this as “using runtime-provided single-sample depth for reprojection”? The logical viewport explanation is useful, but please clarify that foveation is handled by the runtime and this PR consumes its viewport and depth texture.

AdaRoseCannon · 2026-10-15T20:08:21Z

@AdaRoseCannon , your change disables MSAA in WebXR. Are you planning on bringing it back in a follow up PR?

The issue is because the same sample count is needed for all the attachments in the render pass and the WebXR provided depth and colour textures have sampleCount: 1. So without a WebXR supplied depth attachment the colour can be resolved down to write correctly, but that can't be performed for depthStencilTextures as far as I can tell, so when there is a WebXR supplied depth texture then they all need to render single-sample. This is only when there is a WebXR supplied depthTexture though, so Quest should be unaffected.

I wasn't planning a follow up PR. if you have an idea for a solution it would be very welcome

cabanier · 2026-10-15T20:21:49Z

I wasn't planning a follow up PR. if you have an idea for a solution it would be very welcome

I think there's a way to do it but we'll have to teach three.js on how to resolve depth. We can do that after this lands.

…, request depth unless usesDepthValues is false, release the depth record on session end

AdaRoseCannon · 2026-10-15T23:10:19Z

I wasn't planning a follow up PR. if you have an idea for a solution it would be very welcome

I think there's a way to do it but we'll have to teach three.js on how to resolve depth. We can do that after this lands.

Oh nice, thanks!

cabanier · 2026-10-16T01:33:26Z

Your change looks good! There could be instances (ie color mapping) where depth is lost.
I think we can detect when this happens and then print a warning to the console. Alternatively, we can also exit the session.
If we want to add that, it can be in a follow up PR.

AdaRoseCannon · 2026-10-16T21:33:31Z

Your change looks good! There could be instances (ie color mapping) where depth is lost. I think we can detect when this happens and then print a warning to the console. Alternatively, we can also exit the session. If we want to add that, it can be in a follow up PR.

I tested to see what happens if depth isn't provided, it doesn't break everything but the quality of the reprojection drops significantly. This usually looks like warping around objects close to the viewer.

cabanier · 2026-10-16T21:34:54Z

ok, so a warning should suffice.

Mugen87 · 2026-10-23T14:19:51Z

Just for my understanding: DirectRenderPipeline should be the only way WebGPURenderer can be used with VisionOS, right?

Without DirectRenderPipeline, a plain renderer.render() with the default sRGB output (or any tone mapping) needs two render passes (beauty + output). AFAICS, the depth texture the PR requests from VisionOS never gets written in this case. Is that correct?

Mugen87 · 2026-10-23T14:22:29Z

+				if ( xrRenderTarget.depthTexture !== null ) {
+
+					xrRenderTarget.depthTexture.image.width = layerWidth;
+					xrRenderTarget.depthTexture.image.height = layerHeight;


I think this resize is redundant. Textures.updateRenderTarget() does that for you.

Mugen87 · 2026-10-23T14:23:35Z

+			const depthFormat = this._renderer.stencil ? DepthStencilFormat : DepthFormat;
+			const depthType = this._renderer.stencil ? UnsignedInt248Type : UnsignedIntType;
+			depthTexture = new DepthTexture( glProjLayer.textureWidth, glProjLayer.textureHeight, depthType, undefined, undefined, undefined, undefined, undefined, undefined, depthFormat, 2 );
+			depthTexture.isArrayTexture = true;


This line is redundant as well. Textures.updateRenderTarget() should set that flag automatically.

AdaRoseCannon · 2026-10-23T14:32:13Z

Just for my understanding: DirectRenderPipeline should be the only way WebGPURenderer can be used with VisionOS, right?

That's correct.

Without DirectRenderPipeline, a plain renderer.render() with the default sRGB output (or any tone mapping) needs two render passes (beauty + output). AFAICS, the depth texture the PR requests from VisionOS never gets written in this case. Is that correct?

Yes that's correct. A single write without the depth buffer causes some distortion but doesn't make an experience unusable.

Unfortunately the two writes cause foveation to get applied twice which results in pinched appearance which is unusable. We've had some discussions recently in the Immersive Web WG about ways to support multiple render passes with foveation but it still needs further discussion with the WebGPU WG before we can decide on a solution.

cabanier · 2026-10-23T18:11:45Z

Unfortunately the two writes cause foveation to get applied twice which results in pinched appearance which is unusable. We've had some discussions recently in the Immersive Web WG about ways to support multiple render passes with foveation but it still needs further discussion with the WebGPU WG before we can decide on a solution.

FYI @mwyrzykowski and I are working on extending the WebGPU for WebXR spec to clean this up: immersive-web/webxr-webgpu-binding#41

support DirectRenderPipeline on VisionOS by sizing the XR render targ…

68dc022

…et from the projection layer, using its logical viewport, and supplying single-sample foveated depth for reprojection

cabanier reviewed Oct 15, 2026

View reviewed changes

Address review: one XR depth texture with the shared view descriptors…

44ea798

…, request depth unless usesDepthValues is false, release the depth record on session end

Mugen87 reviewed Oct 23, 2026

View reviewed changes

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AdaRoseCannon commented Oct 15, 2026

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