Subject: Re: Picking

From: Dave Stampe-Psy+Eng <dstamp@watserv1>
Date: Tue, 4 Feb 92 18:19:19 -0500

> From [email-masked] Tue Feb  4 12:01:33 1992
> From: [email-masked] (Lance Norskog)
> To: rend386@sunee
> Subject: Picking
> 
> A big difference between a picture-generator library and an 
> interactive graphics library is Picking.  
> 
> Would it be easy to hack the routine so that we could feed it
> coordinates or rectangles and say "don't paint, just return
> a list of the objects you encountered"?
> 
> Lance Norskog
> 

Yes, and we're looking at it.  But it's not gonna be a cheap operation.
You search along a line for object boundary intersections (we use spheres)
then do more expensive tests on those objects.

We are also putting together a 3-d mouse cursor right now-- you move it 
in 3D and surround a vertex or the object you wish to select.  A lit,
tumbling trapezoid sounds nice for a cursor...

- Dave Stampe