[x3d-public] 3D Working Group agenda 23 FEB 2023: progress reports, proposed Metaverse group, glTF extensions, X3D 4.1 feature discussion
Andreas Plesch
andreasplesch at gmail.com
Fri Feb 24 11:57:49 PST 2023
Thanks, Holger and Michalis, very helpful. Andreas
On Fri, Feb 24, 2023 at 2:24 PM Michalis Kamburelis
<michalis.kambi at gmail.com> wrote:
>
> As for image-based lights:
>
> - Indeed, KHR_lights_environment is still only a PR, though from what
> I understood -- it has general support as "good direction". It just
> takes a while to iron out the details.
>
> - The relation to EXT_lights_image_based, as they state themselves:
> "This extension is based on EXT_lights_image_based, with the major
> difference being that KTX2 is used as a container format for cubemap
> textures." https://github.com/KhronosGroup/glTF/pull/1956 . In the
> end, the basic concepts are similar, and X3D EnvironmentLight can
> likely match both.
>
> - In some way, we have it easier in X3D, because we already have
> cubemaps, we have X3DEnvironmentTextureNode . To support KTX or KTX2
> for cubemaps, we don't need to invent here anything - we just use
> ImageCubeMapTexture .
>
> - My notes about it are on
> https://github.com/michaliskambi/x3d-tests/wiki/Image-Based-Lighting-(EnvironmentLight-node)
> . Initial tests on
> https://github.com/michaliskambi/x3d-tests/tree/master/pbr/environment_light
> . Along with some initial implementation in CGE/view3dscene, but it's
> really only initial -- I sample light cubemap, but I use the color
> (most likely) in wrong way.
>
> As for punctual lights:
>
> - See my notes on
> https://github.com/michaliskambi/x3d-tests/wiki/Converting-glTF-to-X3D#punctual-lights
> .
>
> - Reading Holger notes, I think we match exactly in what we do between
> X_ITE and CGE (great!).
>
> - Indeed most parameters have sensible equivalent from glTF to X3D.
>
> - Indeed attenuation is just (0, 0, 1).
>
> - You can take a look at "TPunctualLights.ReadLight" in
> https://github.com/castle-engine/castle-engine/blob/master/src/scene/load/x3dloadinternalgltf.pas#L685
> .
>
> - In Castle Game Engine I added extension to interpret radius = -1 as
> infinity, so when reading glTF I just do "if glTF radius = 0 then X3D
> radius := -1 else X3D radius := glTF radius".
>
> Regards,
> Michalis
>
> pt., 24 lut 2023 o 20:06 Holger Seelig <holger.seelig at yahoo.de> napisał(a):
> >
> > I have done this, as shown below, not handling umbra and attenuation leads to (0, 0, 1):
> >
> > All:
> >
> > light === gltf .light
> >
> > lightNode .color = light .color
> > lightNode .intensity = light .intensity
> >
> > Spot:
> >
> > lightNode .radius = light .range
> > lightNode .cutOffAngle = light .outerConeAngle
> > lightNode .beamWidth = light .innerConeAngle
> > lightNode .attenuation = (0, 0, 1)
> >
> > Point:
> >
> > lightNode ._radius = light .range
> > lightNode ._attenuation = (0, 0, 1);
> >
> > Note that radius 0 means infinity.
> >
> > Best regards,
> > Holger
> >
> > > Am 24.02.2023 um 19:43 schrieb Andreas Plesch <andreasplesch at gmail.com>:
> > >
> > > Hi Holger, Michalis,
> > >
> > > The glTF lights map pretty well to the X3D lights. But there are some
> > > differences in terms of attenuation and umbra and perhaps other
> > > details, I believe. Could you point me to how you deal with these
> > > minor differences before I start to perhaps implement ?
> > >
> > > Thanks, Andreas
> > >
> > > On Fri, Feb 24, 2023 at 1:32 PM Holger Seelig <holger.seelig at yahoo.de> wrote:
> > >>
> > >> X_ITE supports the following extensions:
> > >>
> > >> - KHR_materials_unlit implemented with PhysicalMaterial because of gamma correction.
> > >>
> > >> - KHR_materials_emissive_strength - implemented by adding emissiveStrength field to X3DOneSidedMaterialNode.
> > >>
> > >> - KHR_lights_punctual - mapped to Point/Spot/DirectonalLight
> > >>
> > >> - KHR_texture_transform - mapped to X3D TextureTransform
> > >>
> > >> - KHR_materials_pbrSpecularGlossiness - not really supported, without a SpecularGlossinessMaterial node there will be no real support, but PhysicalMaterial is more straightforward.
> > >>
> > >> Best regards,
> > >> Holger
> > >>
> > >>
> > >>
> > >> Am 24.02.2023 um 19:15 schrieb Michalis Kamburelis <michalis.kambi at gmail.com>:
> > >>
> > >> From others:
> > >>
> > >> 1. Blender: they support a number of extensions at import and export:
> > >> https://docs.blender.org/manual/en/dev/addons/import_export/scene_gltf2.html#extensions
> > >>
> > >> 2. CGE supports ( https://castle-engine.io/gltf ):
> > >>
> > >> - KHR_materials_unlit - unlit materials. This translates nicely to
> > >> X3D4 UnlitMaterial.
> > >>
> > >> - KHR_lights_punctual - define lights (point, spot, directional)
> > >> within glTF file. These translate nicely to X3D lights (with unbounded
> > >> intensity in X3D4).
> > >>
> > >> - KHR_texture_transform - transform (scale, offset, rotate) texture
> > >> coordinates. These translate to X3D texture coordinate transformation
> > >> nodes.
> > >>
> > >> - KHR_materials_pbrSpecularGlossiness - support for alternative
> > >> specification of material parameters using specular-glossiness. Only
> > >> partial support — without textures. Extension considered deprecated by
> > >> Khronos in favor of KHR_materials_specular.
> > >>
> > >> My most important plans:
> > >>
> > >> - X3D nodes for binary meshes (I know X3DOM has this already) and then
> > >> KHR_draco_mesh_compression
> > >>
> > >> - EnvironmentLight in X3D4, consistent with EXT_lights_image_based ,
> > >> KHR_lights_environment .
> > >>
> > >> 3. Everyone: As you see, there is a big overlap between all these
> > >> extension lists (X3DOM, Blender, CGE) and that's good :)
> > >>
> > >> Some glTF extensions are quite popular and in practice supported by
> > >> all/most glTF viewers.
> > >>
> > >> Regards,
> > >> Michalis
> > >>
> > >> pt., 24 lut 2023 o 17:56 Andreas Plesch <andreasplesch at gmail.com> napisał(a):
> > >>
> > >>
> > >> On glTF extension below:
> > >>
> > >>
> > >> ...
> > >> 4. glTF Extensions.
> > >>
> > >> Recent email threads have pointed out that X3D 4.0 normatively references
> > >> glTF 2.0. Meanwhile numerous glTF extensions are available. Nothing
> > >> prohibits X3D browsers/players/tools from going beyond baseline glTF 2.0 -
> > >> the "X" in X3D is Extensible. 8)
> > >>
> > >> There is benefit to software developers, content authors and end users to
> > >> having a shared strategy on what new features to support. Considering and
> > >> supporting such a list is further suitable as a Web3D Recommendation as a
> > >> stepping stone towards future pursuit of X3D 4.1 with International
> > >> Standards Organization (ISO).
> > >>
> > >>
> > >>
> > >>
> > >> Here are a few glTF extensions that have been proposed. Let's discuss which
> > >> have high value and deserve consideration as part of a shared strategy.
> > >>
> > >>
> > >>
> > >> * EnvironmentLight
> > >> * emissiveColor bloom
> > >> * Draco geometry compression
> > >> * Human animation
> > >> * Others?
> > >>
> > >>
> > >> x3dom supports a few extensions:
> > >>
> > >> "KHR_materials_pbrSpecularGlossiness", (now deprecated and replaced by
> > >> KHR_materials_specular)
> > >> "KHR_materials_unlit",
> > >> "KHR_texture_transform"
> > >>
> > >> Soon it will also support Draco decompression.
> > >>
> > >> KHR prefixed extensions are sanctioned by Khronos.
> > >>
> > >> Here is a complete list:
> > >>
> > >> KHR_draco_mesh_compression
> > >> KHR_lights_punctual
> > >> KHR_materials_clearcoat
> > >> KHR_materials_emissive_strength
> > >> KHR_materials_ior
> > >> KHR_materials_iridescence
> > >> KHR_materials_sheen
> > >> KHR_materials_specular
> > >> KHR_materials_transmission
> > >> KHR_materials_unlit
> > >> KHR_materials_variants
> > >> KHR_materials_volume
> > >> KHR_mesh_quantization
> > >> KHR_texture_basisu
> > >> KHR_texture_transform
> > >> KHR_xmp_json_ld
> > >>
> > >> KHR_lights_punctual may be feasible to support, and KHR_xmp_json_ld is
> > >> about metadata and also should be possible to translate to Metadata
> > >> nodes.
> > >>
> > >> EXT_lights_image_based is a multi-vendor extension related to EnvironmentLight
> > >>
> > >> -Andreas
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>
> > >> 5. X3D 4.1 feature discussion. (carried over from last week)
> > >>
> > >>
> > >>
> > >> Many possibilities! The "X" in X3D is Extensible, so pursuit of further
> > >> evolution is an essential part of our design. We benefit from (but are not
> > >> limited by) ISO stability, since implementers can experiment with innovative
> > >> practices and also match Web3D Consortium recommended practices.
> > >>
> > >>
> > >>
> > >> a. Near term: resolving Sound component differences with Web Audio API.
> > >> Some noted issues will likely get deferred as X3D 4.1 issues.
> > >> b. In progress: HAnim2/X3D4 additions for site names, poses, and
> > >> clothing to provide support for apparel.
> > >> c. What else? What's next?
> > >>
> > >>
> > >>
> > >> Wishing best progress. Have fun with X3D! 8)
> > >>
> > >>
> > >>
> > >> 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
> > >>
> > >>
> > >>
> > >> -------------- next part --------------
> > >> An HTML attachment was scrubbed...
> > >> URL: <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20230224/a7f27407/attachment.html>
> > >> -------------- next part --------------
> > >> A non-text attachment was scrubbed...
> > >> Name: smime.p7s
> > >> Type: application/pkcs7-signature
> > >> Size: 5353 bytes
> > >> Desc: not available
> > >> URL: <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20230224/a7f27407/attachment.p7s>
> > >>
> > >> ------------------------------
> > >>
> > >> Subject: Digest Footer
> > >>
> > >> _______________________________________________
> > >> x3d-public mailing list
> > >> x3d-public at web3d.org
> > >> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
> > >>
> > >>
> > >> ------------------------------
> > >>
> > >> End of x3d-public Digest, Vol 167, Issue 76
> > >> *******************************************
> > >>
> > >>
> > >>
> > >>
> > >> --
> > >> Andreas Plesch
> > >> Waltham, MA 02453
> > >>
> > >> _______________________________________________
> > >> x3d-public mailing list
> > >> x3d-public at web3d.org
> > >> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
> > >>
> > >>
> > >> _______________________________________________
> > >> x3d-public mailing list
> > >> x3d-public at web3d.org
> > >> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
> > >>
> > >>
> > >
> > >
> > > --
> > > Andreas Plesch
> > > Waltham, MA 02453
> >
--
Andreas Plesch
Waltham, MA 02453
More information about the x3d-public
mailing list