[X3D-Public] improved validation tests for sound nodes; add ability avoiding audio attenuation altogether

[Don Brutzman]

p.s. here are a few references of additional interest as we consider potential future sound capabilities in X3D v3.4:

- Room reverberation as in the RESound system
	http://gamma.cs.unc.edu/Sound/RESound

- Survey of Methods for Modeling Sound Propagation in Interactive Virtual Environment Systems
	http://www.cs.princeton.edu/~funk/presence03.pdf

- A Review of Spatial Sound for Virtual Environments and Games with Graphics Processing Units
	Foad Hamidi1 and Bill Kapralos
	http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4371579&tag=1

hmmm, if we do want to pursue more advanced sound capabilities, we should probably start a wiki page on X3D Sound and have a working group meeting dedicated to setting up the topic.

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