fix(tsd, rtx): Drop distinlling, improve PTX stitching, CMake#350
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tarcila
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Jul 18, 2026
tarcila
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- Dropping distilling in favor of MDL auxilliary expressions
- Fix possibly invalid version sorting when stitching PTXs
- Only trigger debug renumber if actual debug information when stitching
- Fix a TSD hard error with find_package(pxr) when MaterialX is not found
Replace the distill-to-diffuse tint path for the albedo AOV / denoiser guide with MDL's BSDF auxiliary function (enable_auxiliary), reading a faithful diffuse+glossy albedo straight from the compiled material. Evaluated at normal incidence (k1=shading normal) for a stable, view-independent guide. Removes the mdl_distiller plugin dependency.
stitchPTXs picked the max PTX .version/.target by lexicographic string
compare, which silently downgrades once a field goes multi-digit
(".version 10.0" < "8.5", "sm_100" < "sm_52"). Parse the numeric
major/minor and sm arch and compare as integers instead.
The $L__info_string / .file / .loc renumbering in stitchPTXs is only needed under -lineinfo/-G (Debug, RelWithDebInfo). Detect a .file directive once up front and skip the slow, text-fragile renumbering passes entirely for Release blobs that carry no line info.
Can actually break find_package(pxr) if it ever sets MaterialX_DIR to NOTFOUND. Only the rtx device is actually depending on MaterialX, in the case of TSD, MaterialX is only about an abstract subtype.
jeffamstutz
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Jul 18, 2026
jeffamstutz
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Can we work with USD that doesn't have MaterialX? I suppose the actual USD itself doesn't need MaterialX at runtime to load stages, correct?
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Yes, we can work with any USD build no matter MaterialX is enabled. USD detects MaterialX by itself, if it has been built with it (through find_dependency). Current (unnecessary) MaterialX detection in TSD can break this find_dependency process.
It might need it to correctly parse .mtlx references. But our very own importer does not parse the resulting USDShade graph, so this is a non issue for now. |
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