[X3D-Public] X3dom + PROTO; special profiles?

Don Brutzman brutzman at nps.edu
Tue Nov 10 02:16:58 PST 2009


Hi Johannes.  It is not clear to me what the rationale for your HTML
profile is.  It would be important to list a broad common set of use
cases and corresponding constraints for deployment which would justify
a dedicated profile.

As an example, I think that such use cases could be made for a Mobile Profile
that might add a few things to the already-existing X3D Interactive Profile.
The constraints are a need for lightweight scenes (due to limited bandwidth)
that can be handled by deployed simple-capability hardware on mobile devices.
Good cross-checks on such a profile would be to approximately match the
demands/capabilities set by OpenGL ES for Embedded Systems and the SVG mobile
profiles (Tiny and Basic).
	http://www.w3.org/TR/SVGMobile
	http://www.khronos.org/opengles

As a counterexample:  when I author HTML pages, in general i plan for the
general web user who typically has a highly capable desktop or laptop system.
so as an author i'd want to be able to use X3D Full Profile with HTML, likely
including networked avatars with physics etc. over X3D Earth locations, since
there are no general bandwidth or hardware constraints to constrain the
capabilities of Web users interacting with such scenes.

In support of what you are saying, of course it is possible today to properly
declare the support you've defined using Interactive Profile and a number of
component tags.  (That might be worth enumerating).  If indeed a number of
scenes commonly find that level of X3D capability useful, that is good evidence
of the author-driven use cases which might justify defining a new profile.

If the rationale for a new profile is what can be done overlaying a javascript
X3D viewer over a WebGL layer in an HTML browser, then support for XML parsing
and different image formats might be assumed available.  Maybe such a
"no-plugin profile" might be tied to WebGL or O3D limitations.  Hard to say
if those rendering-layer APIs will have any particular barriers preventing
implementation of a full-capability X3D player on top - a clever X3D player
could likely implement most X3D capabilities given some workable form of a
good rendering API to build on.

p.s. for those interested:  more thoughts on components, profiles and related
extensibility topics can be found in _X3D for Web Authors_ Chapter 1
which is online at
	http://x3dgraphics.com
	http://x3dgraphics.com/chapters/Chapter01-Technical_Introduction.pdf
	[after some generalities, details on pp. 12-16]

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  work +1.831.656.2149
X3D, virtual worlds, underwater robots, XMSF  http://web.nps.navy.mil/~brutzman




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