Added first set of texture file format tests

[AlexSchwank]

• JPEG, CMYK, 8-bit
• JPEG, RGB, 8-bit
• JPEG, Grayscale, 8-bit
• PNG, Grayscale 8-bit
• PNG, Grayscale, 16-bit
• PNG, RGB, 8-bit
• PNG, RGB, 16-bit
• PNG, RGB, 32-bit

[AlexSchwank]

I'll add the source PSD after the group has discussed if this is good to go.

[meshula]

This looks great :)

Would it would be possible to attach in a readme perhaps, a little snippet of code (Python? C++? doesn't really matter) to generate the color and grayscale strip for the top scanline? That would allow the construction of unit tests that procedurally generate the gradient, open the image file, and then do a variety of baseline metrics versus expected values.

If the images were generated using photoshop tools, could I request that we generate the gradients procedurally instead? This would really help in tracing down one bit encoding errors that sometimes occur with formats like jpeg.

[jcowles]

hmm, lots of errors in like this Run usdchecker:

Checking test_assets/TextureFileFormatTests/png_rgb_8-bit.usda
Traceback (most recent call last):
  File ".github/usdchecker.py", line 149, in <module>
    sys.exit(main())
  File ".github/usdchecker.py", line 118, in main
    checker.CheckCompliance(inputFile)
  File "/home/runner/.local/lib/python3.7/site-packages/pxr/UsdUtils/complianceChecker.py", line 1138, in CheckCompliance
    self._TraverseRange(allPrimsIt, isStageRoot=True)
  File "/home/runner/.local/lib/python3.7/site-packages/pxr/UsdUtils/complianceChecker.py", line 1196, in _TraverseRange
    self._CheckPrim(prim)
  File "/home/runner/.local/lib/python3.7/site-packages/pxr/UsdUtils/complianceChecker.py", line 1[182](https://github.com/usd-wg/assets/actions/runs/8251260090/job/22567886066?pr=80#step:7:183), in _CheckPrim
    rule.CheckPrim(prim)
  File "/home/runner/.local/lib/python3.7/site-packages/pxr/UsdUtils/complianceChecker.py", line 714, in CheckPrim
    Sdr.Registry().GetShaderNodeByIdentifier(shaderId)
pxr.Tf.ErrorException: 
	Error in 'pxrInternal_v0_24__pxrReserved__::_GetShaderResourcePath' at line 53 in file /opt/USD/pxr/usd/usdHydra/discoveryPlugin.cpp : 'Failed verification: ' !path.empty() ' -- Could not find shader resource: shaderDefs.usda

[meshula]

@jcowles Is there an error in the checker? It's reporting

pxr.Tf.ErrorException: 
	Error in 'pxrInternal_v0_24__pxrReserved__::_GetShaderResourcePath' at line 53 in file /opt/USD/pxr/usd/usdHydra/discoveryPlugin.cpp : 'Failed verification: ' !path.empty() ' -- Could not find shader resource: shaderDefs.usda

but shaderDefs.usda isn't something originating with this PR. (Or I can't spot it)

[jcowles]

not sure what's happening there

[AlexSchwank]

PixarAnimationStudios/OpenUSD#3055

Description of Issue
usdchecker now has tests that depend on usdShaders, introducing an (indirect) dependency on imaging.
This means that tests cannot successfully complete when building without imaging.

[pablode]

I tried manually copying the relevant file, but it doesn't seem that easy to fix. We could lock usdchecker at v24.03 until this issue is resolved - I've set up the PR above.

[AlexSchwank]

Thanks @pablode . Happy to lock the USD version to a specific one.

[jcowles]

@AlexSchwank mind merging main (or rebasing) into your branch and pushing again to this to get it to re-run usdchecker?

(I tried just hitting re-run, but I think it's running against the version of main your branch is at)