Add color4 type to Sdr

[seando-adsk]

Description of Change(s)

As discussed in https://groups.google.com/g/usd-interest/c/G8BSo8jzfyY

Fixes Issue(s)

This allows differentiating between color4 and vector4 input types at the Sdr
level when inspecting MaterialX shader nodes.

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[jilliene]

Filed as internal issue #USD-7413

[spiffmon]

@seando-adsk and @JGamache-autodesk , we're reviewing this, and I have a followup question, which is whether there is need to update any HdMtlx and/or Storm code to handle color4 for passing data back into MaterialX codegen?

That could be followup work, for sure, along with untangling the OSL component.

[JGamache-autodesk]

Hi @spiffmon, the reconversion back to MaterialX was working before (and after) this fix. The hdMtlx code uses the type found in the MaterialX NodeDef and since the C++ representation of both float4 and color4 is GfVec4f, the values were converted correctly. I did not see any Hydra/Storm issues before, and none were introduced by this fix.

[spiffmon]

Thank you, @JGamache-autodesk - great to hear!

…

--spiff

On Tue, Aug 23, 2022 at 2:48 PM JGamache-autodesk ***@***.***> wrote: Hi @spiffmon <https://github.com/spiffmon>, the reconversion back to MaterialX was working before (and after) this fix. The hdMtlx code uses the type found in the MaterialX NodeDef <https://github.com/PixarAnimationStudios/USD/blob/release/pxr/imaging/hdMtlx/hdMtlx.cpp#L231> and since the C++ representation of both float4 and color4 is GfVec4f, the values were converted correctly. I did not see any Hydra/Storm issues before, and none were introduced by this fix. — Reply to this email directly, view it on GitHub <#1894 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABPOU2HZS26WAPGB3P7JCDLV2VBKLANCNFSM5YDSR7NQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>