[x3d-public] [x3d] Spec Comment by on 19775-1: X3D Architecture - V4.0

[Michalis Kamburelis]

1. I interpreted the "FACTOR" in CGE/view3dscene just like FreeWRL. That
is, "FACTOR" indicates to use MultiTexture.color / MultiTexture.alpha. I
see I even call it "constant factor" in CGE/view3dscene code, to make a
point that it is constant for the whole "execution" of this MultiTexture
calculation.

I think this was invented to correspond to old fixed-function OpenGL
"glTexEnvv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, ...)".

I believe the spec should be fixed, the existing sentence indeed is
incorrect, as there are no "factors at particular stages".

From

"""
The texture argument is the factor (color, alpha) from the texture provided
for the current stage of the MultiTexture node.
"""

->

"""
The texture argument is the factor from MultiTexture node <i>color</i> and
<i>alpha</i> fields.
"""

2. There's no alignment here with glTF -- glTF doesn't have MultiTexture.

And, also because there are numerous problems with X3D MultiTexture unfixed
for many years and it doesn't seem it is used by authors, I proposed in
https://castle-engine.io/x3d_multi_texturing.php and
https://github.com/michaliskambi/x3d-tests/wiki/Deprecate-some-unused-and-badly-specified-MultiTexturing-specification-pieces
that we just deprecate parts of it (leaving only some core functionality
subset, to just sum and multiply textures).

Regards,
Michalis

śr., 15 cze 2022 o 18:48 Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
napisał(a):

> Thanks Doug… am not sure.  Have shared with x3d-public for further
> scrutiny.
>
>
>
> Michalis, when defining FACTOR, can we say things more clearly to ensure
> good alignment with glTF approaches?
>
>
>
> all the best, Don
>
> --
>
> Don Brutzman  Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu
>
> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA
> +1.831.656.2149
>
> X3D graphics, virtual worlds, Navy robotics https://
> faculty.nps.edu/brutzman
>
>
>
> *From:* GPU Group <gpugroup at gmail.com>
> *Sent:* Wednesday, June 15, 2022 9:28 AM
> *To:* Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
> *Cc:* x3d at web3d.org
> *Subject:* Re: [x3d] Spec Comment by on 19775-1: X3D Architecture - V4.0
>
>
>
> Sorry I was reading the committee draft, SELECT arg2 has been corrected in
> Draft International Standard.
>
> But the confusion on the other one, FACTOR is still there
>
>
> in freewrl looks like we've been using Multitexture.color and .alpha when
> source is FACTOR.
>
> And those values are provided once by Multitexture for all stages
>
> Hypotheses:
>
> H0: freewrl has been doing it wrong
>
> H1: spec is unclear
>
> "FACTOR"
>
> The texture argument is the factor (color, alpha) from the texture
> provided for the current stage of the MultiTexture node.
>
>
>
> On Tue, Jun 14, 2022 at 2:35 PM Brutzman, Donald (Don) (CIV) <
> brutzman at nps.edu> wrote:
>
> Thanks Doug.  Entered as Mantis 1397
>
>
>
> * Mantis 1397: Fix typo Table 18.3 — Multitexture values for mode field
>
> * https://www.web3d.org/member-only/mantis/view.php?id=1397
>
> *
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/components/texturing.html#t-MultitextureModes
>
>
>
> Change applied in git, ready for editor review/resolution (when Dick and I
> next get together).  This should make it time for ISO DIS submission, they
> are currently reviewing figures prior to acceptance.
>
>
>
> all the best, Don
>
> --
>
> Don Brutzman  Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu
>
> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA
> +1.831.656.2149
>
> X3D graphics, virtual worlds, Navy robotics https://
> faculty.nps.edu/brutzman
>
>
>
> -----Original Message-----
> From: x3d <x3d-bounces at web3d.org> On Behalf Of Spec Feedback
> Sent: Tuesday, June 14, 2022 1:15 PM
> To: x3d at web3d.org
> Subject: [x3d] Spec Comment by on 19775-1: X3D Architecture - V4.0
>
>
>
> -- Submitter indicates that this comment may be public: *Yes* --
>
>
>
> Comment on 19775-1: X3D Architecture - V4.0
>
> 18.4.3 MultiTexture
>
>
> https://www.web3d.org/documents/specifications/19775-1/V4.0/Part01/components/texturing.html#MultiTexture
>
>
>
> -----------------
>
> "SELECTARG2"   Use color argument 1
>
> Arg2
>
> should be
>
> "SELECTARG2"   Use color argument 2
>
> Arg2
>
> -----------------
>
>
>
> Submitted on Tuesday, 2022,  June 14 - 1:15pm by  (Doug Sanden )
>
> IP: 23.17.48.2
>
>
>
> See: https://www.web3d.org/node/1694/submission/6179
>
>
>
>
>
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