[x3d-public] Summary of Layout/Layer component nodes usage after suggested fixes

[Don Brutzman]

cc: x3d-public

Roy is shining a light on some tricky issues.

These nodes are an area of X3D specification refinement that has suffered from a lack of example scenes.

Does anyone have (or know of) X3D scenes that demonstrate intended operation of nodes in the Layer and Layout components?

35  Layering component
http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/layering.html

36  Layout component
http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/layout.html


On 5/26/2015 11:11 AM, Roy Walmsley wrote:
> Don,
>
> I have now reported on issues with both the Layout node and the LayoutGroup node. The first was by specification comment and Mantis issue (693). The second by X3D WG mail.
>
> I suggested for the Layout node that the /X3DLayoutNode/ inheritance should be changed from /X3DChildNode/ to /X3DNode/.
>
> I suggested for the LayoutGroup node that the DTD and the Schema should be modified to match the restricted usage in the specification.
>
> Where does this leave the overall usage situation?
>
> The LayoutGroup can only be a child of itself and the LayoutLayer node.
>
> The LayoutLayer node can only be a child of the LayerSet node (this is consistently defined).
>
> Thus the use of the Layout and Layer component nodes is illustrated by the extract in the following example – first in XML encoding, second in classic VRML encoding.
>
> <LayerSet>
>
>                  <Layer/>
>
>                  <LayoutLayer>
>
>                                  <Layout/>
>
>                                  <Viewport/>
>
>                                  <LayoutGroup>
>
>                                                  <Layout/>
>
>                                                  <Viewport/>
>
>                                                  <LayoutGroup>
>
>                                                                  <Layout/>
>
>                                                                  <Viewport/>
>
>                                                  </LayoutGroup>
>
>                                  </LayoutGroup>
>
>                  </LayoutLayer>
>
> </LayerSet>
>
> LayerSet {
>
>      layers [
>
>          Layer {}
>
>          LayoutLayer {
>
>              layout Layout {}
>
>              viewport Viewport {}
>
>              children [
>
>                  LayoutGroup {
>
>                      layout Layout {}
>
>                      viewport Viewport {}
>
>                      children [
>
>                          LayoutGroup {
>
>                              layout Layout {}
>
>                              viewport Viewport {}
>
>                          } #LayoutGroup
>
>                  } #LayoutGroup
>
>              ]
>
>          } #LayoutLayer
>
>      ]
>
> } #Layerset
>
> Note the example is only intended to illustrate how the nodes are placed in a valid scene graph, and nothing more.
>
> Roy
>


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