RE: Does Performer support the "Basics"

New Message Reply Date view Thread view Subject view Author view

Jeff Brickley (jbrickley++at++lmwsmr.lesc.lockheed.com)
Fri, 20 Sep 1996 10:06:09 -0700

 ----------
From: Bob Gustafson
To: info-performer
Subject: Does Performer support the "Basics"
Date: Thursday, September 19, 1996 2:13PM

Hi,

I've been doing this graphics thing for several years, but I can't for the
life
of me figure out how to draw
a couple of polylines extending out from the wingtip of an aircraft. We use
this method (in other systems)
to indicate wing trails. How do I draw a couple of simple polylines
attached
to my aircraft image???
===============
     I've done this in our application with a post-draw routine. I store
the coordinates of the object drawn and store history information, replaying
the history data in a poly-line using OpenGL calls. This will draw a single
line from the "origin" of your model, however, to draw from your wingtips,
you will have to calculate the offsets based on the orientation of the
aircraft if you use our method.
===============
Another question related to "basics". Is there any way to attach a 2D
character string, again to an
aircraft? Right now, we are using a 3D pfString for displaying an aircraft
number next to the aircraft's
image but unless the orientation of the number is continually updated, it
can
become unreadable
(upside-down, backwards...) a 2D number won't have this problem. So, the
question is: how to "attach" a 2D
number (charstr) to a 3D performer aircraft image.
================
Once again, by storing the location in memory and calling it from a
post-draw routine we display object identification using bitmapped-text in
OpenGL. Bitmapped text can still be positioned using 3D-coordinates,
however it ALWAYS displays the correct orientation. Another technique which
we just recently encorporated is a little more difficult, that is to take
the screen projection and identify the "screen" coordinates of the object.
 An Ortho projection will then allign any object with the screen.

I receive this E-Mail on a PC quite a distance from our SGI, so I cannot yet
give you code examples. However, if you need further explanations and/or
code examples, I'll gladly give the help I can!

=======================================================================
List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/
            Submissions: info-performer++at++sgi.com
        Admin. requests: info-performer-request++at++sgi.com

New Message Reply Date view Thread view Subject view Author view

This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:53:35 PDT

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.