[x3d-public] Shadows

[Andreas Plesch]

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
> >
> > _______________________________________________
> > x3d-public mailing list
> > x3d-public at web3d.org
> > http://web3d.org/mailman/listinfo/x3d-public_web3d.org



--
Andreas Plesch
Waltham, MA 02453