[x3d-public] X3D 4.0 specification problem: upVector field for TextureProjector, TextureProjectorParallel

[Holger Seelig]

That is very good news. I will update X_ITE accordingly.

Maybe now is also the time to change the *direction* vector to (-1 -1 -1) on the example page https://www.web3d.org/x3d/content/examples/Basic/X3dSpecifications/TextureProjectorComponentExampleIndex.html, then the projector would point exactly into the corner of the model.

Best regards,
Holger

--
Holger Seelig
Leipzig, Germany

holger.seelig at yahoo.de
https://create3000.github.io/x_ite/

> Am 08.12.2024 um 05:21 schrieb Brutzman, Donald (Don) (CIV) via x3d-public <x3d-public at web3d.org>:
> 
> While performing regression testing using X3D Examples Archive, found several problems related to the upVector field.
> 
> First, upVector is defined in X3D Architecture specification for TextureProjector node but not TextureProjectorParallel node.  However the corresponding figures illustrate that upVector is an integral part of each node's definition.
> 
> Second, the default value is "0 0 1" but this looks wrong (rotated confusingly), and a much-more intuitive value is "0 1 0" with y-axis up.  In other words, the default upVector direction ought to point upwards.  This is the default relationship is shown in both figures and the specification example for TextureProjector.
> X3D 4.0 Architecture, clause 42 Texture projection component
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/textureProjection.html
> 
> 42.3.1 X3DTextureProjectorNode
> 
> 42.4.1 TextureProjector
> Figure 42.5 — Description of 3D perspective texture projection
> "The upVector describes the roll of the camera by saying which point is "up" in the camera's orientation. The default value of this field is (0 0 1)."
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/textureProjection.html#TextureProjector
> 
> 42.4.2 TextureProjectorParallel
> Figure 42.4 —Description of 3D parallel texture projection
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/textureProjection.html#TextureProjectorParallel
> Third, I am unable to find a working implementation for these nodes, though we have seen FreeWrl (at least) working in the past.
> 
> Recommended specification remedies:
> Include upVector field in TextureProjectorParallel node and shared node type X3DTextureProjectorNode
> Change default values to "0 1 0"
> Include an example for TextureProjectorParallel node, similar to TextureProjector node
> Fix erroneous figure labels so that they are properly numbered
> Update Mantis error tracker, various validation tools, X3D Tooltips, X3DJSAIL and X3DPSAIL x3d.py, etc.
> Encourage, hopefully ensure that multiple browser implementations are available.
> Test scene:
> X3D Example Archives: Basic, X3D Specifications, Texture Projector Component Example
> https://www.web3d.org/x3d/content/examples/Basic/X3dSpecifications/TextureProjectorComponentExampleIndex.html
> Thanks in advance for all feedback on these corrections, plus any implementation reports.
> 
> all the best, Don
> --
> Don Brutzman  Naval Postgraduate School, Code USW/Br        brutzman at nps.edu <mailto: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
>  
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