Re: 2D text in a 3D world

steve ([email protected])
Thu, 15 Jun 1995 09:15:27 GMT0BST


> A couple of guys here at Boeing have done just exactly this for an
> interface to the computer while in an immersive VR invironment. They
> have a "window" that appears to be held in one hand ( and moves in full
> 6D with the tracked hand ). In this window, any 2D data can be
> displayed, in particular, HTML. They have also worked out a method
> whereby a finger on the other hand is tracked and this window becomes a
> virtual touch sensitive screen. It was not hard to do.

It is simple to do - simple 'render' the text into a texture map
buffer, and apply that texture to a surface. Hey Presto, 2D text in
a 3D world. Most interactive systems include vertex-level collision
detection, so detecting where the pointer (hand, ma> e, glove etc.)
hits the virtual panel is also simple, and transforming this 3D
location into 2D is simply a matter of applying the inverse transform
for the base object to the collision coordinate - you end up with a
2D coordinate (relative to the top of the p if things are set up
correctly) and this can be used to find an index into the text.

Dynamic update of textures is a trick regularly used in real-time
simulation and VR systems - animation and special effects like flames
etc. are provided by cycling through a number of texture images at
some pre-defined rate.

Putting 'dynamic' text like HTML onto a polygon is exactly the same.
Of cour e, you have to render the text into the texture buffer, but
that is not too hard.

=========================
Steve Ghee ( [email protected] )
Director of Technology

Division Ltd
19 Apex Court
Woodlands
Almondsbury
Bristol, UK
BS12 4JT
Tel : +44 1454 615554
Fax : +44 1454 615532
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