Bug 256724 – [WebGPU][WGSL] sampling a texture_external should expand to two samples

• Component: WebGPU
• Status: RESOLVED FIXED

[Mike Wyrzykowski]

In WGSL if we have:

  texture_external t;
  vec4<f32> result = textureSampleBaseClampToEdge(t, sampler, normalizedCoordinates);

or:

  texture_external t;
  vec4<f32> result = textureLoad(t, pixelCoordinates, levelOfDetail);


we should expand this to:

    auto coords = t_UVRemapMatrix * normalizedCoordinates;
    auto y = t_FirstPlane.sample(sampler, coords).r;
    auto cbcr = t_SecondPlane.sample(sampler, coords).rg;
    auto ycbcr = float3(y, cbcr);
    float4 result = float4(t_ColorSpaceConversionMatrix * float4(ycbcr, 1), 1);
    

or:
   
    auto coords = t_UVRemapMatrix * pixelCoordinates;
    auto y = t_FirstPlane.read(coords, levelOfDetail).r;
    auto cbcr = t_SecondPlane.read(sampler, levelOfDetail).rg;
    auto ycbcr = float3(y, cbcr);
    float4 result = float4(t_ColorSpaceConversionMatrix * float4(ycbcr, 1), 1);

[Radar WebKit Bug Importer]

<rdar://problem/109273173>

[Tadeu Zagallo]

Pull request: https://github.com/WebKit/WebKit/pull/13916

[EWS]

Committed 264141@main (6c82c6b0b152): <https://commits.webkit.org/264141@main>

Reviewed commits have been landed. Closing PR #13916 and removing active labels.