MaterialX texcoord-related regression in v24.03

[pablode]

Description of Issue

Following asset looks different after upgrading USD: Buffer_Interleaved_01.zip

v23.08

v24.03

(see comment below for an explanation)

Steps to Reproduce

1. open the asset in usdview

System Information (OS, Hardware)

Occurs on both Windows (OpenGL) and macOS (Metal)

Package Versions

v24.03 and v24.05 are affected

Build Flags

--openimageio --opencolorio

[pablode]

I believe to have found the cause. First, the texture coordinates are faulty:

texCoord2f[] primvars:st0 = [(0, 1), (1, 0), (5.831554e-39, 1), (0, 1), (5.831554e-39, 1), (0, 1)] (
    interpolation = "vertex"
)

However, they are irrelevant because the BaseColor_Grey.png texture that is being sampled is 100% grey and is defined with the periodic address mode in both u and v directions. Hence, regardless of UV values, grey should be returned and not black.

Although on macOS the color is solid black, I have observed flickering of the correct colors with the OpenGL backend. Perhaps this is somehow related to the newly-introduced tangent frame computation?

[jesschimein]

Filed as internal issue #USD-9565

[pablode]

On macOS, I can't reproduce this anymore with usdview, but it's 100% reproducible with usdrecord.
usdrecord Buffer_Interleaved_01/Buffer_Interleaved_01.usda bug.png to get above render.

[pablode]

Can't reproduce with USD v24.11.