[x3d-public] TwoSidedTexture node

[Don Brutzman]

On 11/4/2017 2:41 PM, Andreas Plesch wrote:
> Yeah, the spec at
> http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/rendering.html#CommonGeometryFields
> is clear that solid=true means no back faces are displayed, no matter
> what else is going on. I agree that behaviour is cleanest and probably
> what most/all browsers follow. It may be worth having a tooltip hint
> for TwoSidedMaterial which points out that solid=false is required to
> display the back faces.

great idea, tooltip added.

http://www.web3d.org/x3d/content/X3dTooltips.html#TwoSidedMaterial

"Warning: corresponding geometry within the parent Shape must have solid='false' for two-sided rendering, otherwise no reverse-side geometry is displayed."

> Following the TwoSidedMaterial approach of having a single node
> dealing with both sides, it is probably preferable to think about a
> TwoSidedAppearance node implementing X3DAppearanceNode rather than an
> additional BackAppearance node.

Wondering if it might be better to modify Appearance instead, adding a backTexture field?  That way no new node is needed.

Not sure why we didn't take that approach with TwoSidedMaterial in the first place, adding a backMaterial field instead of a new node?  Seems to be more flexible... perhaps something to do with TwoSidedMaterial boolean separateBackColor field; however that field might migrate up Appearance as well.

This will be good to think through for designing best possible consistency for X3D v4.0.  Deprecating a superfluous node is always an option.

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