[x3d-public] Shadows

[Michalis Kamburelis]

Yes, (almost) exactly.

The only change I would do to what Don wrote is that I would start by
making shadowIntensity initializeOnly, i.e. [] instead of [in,out]. While
changing it at runtime is possible (as with everything), it could have very
big cost when changing from 0 to 1. I'm not strongly opposed to [in,out],
just saying I would start with [] and see at adoption in browsers and think
about "upgrading" to [in,out] in next version.

Regards,
Michalis

W dniu pon., 5.10.2020 o 21:50 Don Brutzman <brutzman at nps.edu> napisał(a):

> Specifics please: are you gentlemen talking about adding
> backwards-compatible field signature of
>
>
>
>    SFFloat [in,out] shadowIntensity  0     [0,1]
>
>
>
> to X3DLightNode (and thus DirectionalLight, PointLight, SpotLight)?
>
>
>
>
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-WD2/Part01/components/lighting.html#X3DLightNode
>
>
>
> =============================================
>
> 17.3.1 X3DLightNode
>
>
>
> X3DLightNode : X3DChildNode {
>
>    SFFloat [in,out] ambientIntensity 0     [0,1]
>
>    SFColor [in,out] color            1 1 1 [0,1]
>
>    SFBool  [in,out] global           FALSE
>
>    SFFloat [in,out] intensity        1     [0,∞]
>
>    SFNode  [in,out] metadata         NULL  [X3DMetadataObject]
>
>    SFBool  [in,out] on               TRUE
>
> }
>
> =============================================
>
>
>
>
>
> On 10/5/2020 7:08 AM, Andreas Plesch wrote:
>
> >
>
> > I think the exact interpretation of intermediate values would be
>
> > implementation dependent in any case. It may be ok to just stay that.
>
> >
>
> > "
>
> > shadowIntensity ranges from 0 to 1.0 [could be omitted because the
>
> > range is defined in the signature]. A value of 0, the default, has no
>
> > effect. A value of 1.0 has the effect that no light emitted by the
>
> > node reaches the areas where shadows are cast by shapes in the scope
>
> > of the light. A value between 0 and 1.0 has the effect that an
>
> > intermediate amount of light reaches shadowed areas. Support for
>
> > intermediate values is browser dependent.
>
> > "
>
> >
>
> > Only shapes in the scope of a light can cast shadows since only those
>
> > shapes are lit by the light. One general question then is which shapes
>
> > should be able to receive shadowing. Potentially all shapes in the
>
> > scene but perhaps it makes sense to restrict receiving shapes also to
>
> > the scope of the light ? The wording above does not offer further
>
> > detail which would mean that the browser is given room to answer that
>
> > question.
>
> >
>
> > -Andreas
>
> >
>
> >
>
> > On Mon, Oct 5, 2020 at 6:56 AM Michalis Kamburelis
>
> > <michalis.kambi at gmail.com> wrote:
>
> >>
>
> >>  From Castle Game Engine / view3dscene side, I can go for "SFfloat
>
> >> shadowIntensity" with this interpretation too :)
>
> >>
>
> >> Compared to my earlier proposal "SFBool shadows", the
>
> >> "shadowIntensity" is obviously more flexible, I can see the
>
> >> advantages. And with shadow maps, it is easy to support any
>
> >> intermediate value, e.g. allow 0.5 of the light to reach the surface.
>
> >>
>
> >> With shadow volumes it's not possible (at least not easily) but then
>
> >> the implementation can always go with simple Andreas' wording """0
>
> >> means no shadows, 1 means full shadow.""". We would need to say what
>
> >> happens for intermediate values in this case, e.g. "if implementation
>
> >> only supports 0.0 and 1.0, then any value >= 0.5 behaves like 1.0,
>
> >> otherwise (value < 0.5) behaves like 0.0".
>
> >>
>
> >> Regards,
>
> >> Michalis
>
> >>
>
> >> pon., 5 paź 2020 o 04:49 Andreas Plesch <andreasplesch at gmail.com>
> napisał(a):
>
> >>>
>
> >>> As motivation to make Shadows a high priority for the next version let
>
> >>> me share Holger's cool idea to use Sponza for shadows:
>
> >>>
>
> >>>
> https://create3000.github.io/media/examples/Navigation/NavigationInfo/example.html
>
> >>>
>
> >>> I could adopt it pretty much as is for x3dom:
>
> >>>
>
> >>>
> https://raw.githack.com/andreasplesch/x3dom/scopedLights/test/functional/scopedLights/inline.html
>
> >>>
>
> >>> (without the nice ParticleSystem, and with slightly changed
>
> >>> intensities and locations).
>
> >>>
>
> >>> The main required field for both x3dom and x_ite to enable shadows is
>
> >>> shadowIntensity. 0 means no shadows, 1 means full shadow.
>
> >>>
>
> >>> -Andreas
>
> >>> --
>
> >>> Andreas Plesch
>
> >>> Waltham, MA 02453
>
>
>
> 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
> http://faculty.nps.edu/brutzman
>
>
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