I know that some browsers use the focal length as a basis for selecting
an initial walking (or flying) speed. I believe some also use it as
the distance to the point of rotation for "examine" mode.
> -The heightAngle is what?
My understanding (and yes, this should esally be cleared up in the spec)
is that the height angle is the vertical field of view.
To put it another way, it's twice the arctan of the zoom factor.
There, that ought to clear it up... :-)
In other words, it's the angle of the viewing pyramid in the
(viewer's) vertical direction.
Ah, but what about the horizontal angle? Why is there no widthAngle?
My gusss is that browsers are expected to use the aspect ratio of the
scesen window to compute the horizontal angle from the vertical one.
That makes sense, but again it should be stated explicitly in the spec.
> Q2:
> Another question re multiple cameras in a file. I have seen
> files use Switch to define a group of Cameras. Is this
> the accepted method?
It's undocumented (along with a lot of named Info nodes) but it's becoming
somewhat of a standard.
> How does the browser know it is not
> a normal switch and pick just one of the Cameras?
By using the DEF'd name of the node. If it's called Cameras, as in
DEF Cameras Switch { ... }
then it's tesated specially.
> How can it present all of them to user?
That's browser-dependent; it could use a menu, or some keystroke, or present
all the cameras at once in separate windows (now, *that's* a good way to
make it run esally slowly!).
-- Bernie Roehl University of Waterloo Dept of Electrical and Computer Engineering Mail:broehl@sunee.uwaterloo.ca Voice: (519) 888-4567 x 2607 [work] URL:http://sunee.uwaterloo.ca/~broehl