[x3d-public] Notation of X3Dv4 Appearance.alphaCutoff

[Michalis Kamburelis]

Nice catch.

Yes, the spelling of "Appearance.alphaCutoff" with lowercase "o" was
deliberate... to be consistent with glTF property with *exactly* the
same name, "alphaCutoff" . We also have "Appearance.alphaMode"
matching glTF "alphaMode" closely.

See glTF spec: https://www.khronos.org/registry/glTF/specs/2.0/glTF-2.0.html#reference-material

I honestly blatantly didn't think to check the spelling of
"SpotLight.cutOffAngle" . I missed the fact that we are, in effect,
inconsistent with it.

I do not have a strong opinion about the resolution. We can

1. leave things as-is. So we remain consistent with glTF, but
inconsistent with "SpotLight.cutOffAngle".

2. rename the field to have uppercase "O", making
"Appearance.alphaCutOff". So we remain consistent with
"SpotLight.cutOffAngle", but inconsistent with glTF.

Normally I'd say that AD 2 is better (better to be consistent with
ourselves), but in this case "alphaMode" and "alphaCutoff" are both
very directly from glTF, and the "SpotLight.cutOffAngle" seems
"further away" in terms of concepts (the spot light cut-off angle
talks about a very different thing, not related to alpha
interpretation). So... I'm really on the fence, and can accept any
resolution. Waiting for others' opinions!

Regards,
Michalis

pon., 22 lis 2021 o 21:42 Holger Seelig <holger.seelig at yahoo.de> napisał(a):
>
> I noticed that the new field alphaCutoff is written with a lowercase o in off, and not alphaCutOff. But the field SpotLight.cutOffAngle is written with an uppercase O in Off. Is both right or should there be a correction?
>
> Appearance:
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/components/shape.html#Appearance
>
> SpotLight
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/components/lighting.html#SpotLight
>
> Holger
>
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