From: Curtis Lisle (clisle++at++sgi.com)
Date: 09/03/2002 08:09:43
Regarding the WGS84 to local coordinate conversion:
This application of coordinating Earth-based geodetic coordinates and
orientations with a local HPR in a flat earth, cartesian coordinate system
can be complex. In my opinion, it needs to be treated consistently and
coordinated with the way any databases are made for your application. If
you are going to be integrated with other simulators working in other
coordinate systems, this is especially important.
One set of information regarding geographic coordinate systems is the SEDRIS
program, that is available internationally. They have a "spatial reference
model" which deals with coordinate system mapping and is oriented towards
the problem you have. SEDRIS is a huge software system, but you might find
use for just their coordinate conversions. If you are interested, check
out http:://www.sedris.org and select the Spatial Reference Model info. I
wish you success!
Curtis
-----Original Message-----
From: info-performer++at++sgi.com
To: allan++at++holodeck.engr.sgi.com
Sent: 8/31/02 5:00 AM
Subject: info-performer Aug 30 2002
Welcome to the info-performer mailing list DIGEST for August 30 2002
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Message Subjects:
Re: [info-performer] WGS84 (psi,theta,phi) -> local performer hpr?
Re: [info-performer] limit color values with blending ?
[info-performer] Re: limit color values with blending ?
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From: "Serge Kourdakov" <serge++at++sat-sim.org>
Date: Thu, 29 Aug 2002 13:50:51 +0400
Subject: Re: [info-performer] WGS84 (psi,theta,phi) -> local performer
hpr?
Hi Ken
you wrote.
-----------------------------------------------------
Given psi,theta and phi (in WGS84 coords) and a local lat/lon, does
anybody have a good algorithm for calculating the flatearth HPR for
performer? I've searched the archives and found several references on
converting wgs and lat,lon to xyz, but I haven't been able to find any
references to converting the orientation. Thanks.
------------------------------------------------------
My idea is that though angles could be different
http://mathworld.wolfram.com/EulerAngles.html
or
http://users.ece.gatech.edu/~slabaugh/personal/research/euler/euler.pdf
etc ....
the resulting cosine direction matrix should be the same (though just
maybe
I'm wrong ..).
Thus you might compute cosine direction matrix in one set of angles .
Then extract angles in another way to present rotations ...
So take a look at pdf for some hints how to extract angles for the
matrix..
And the way might be such as - using your psi,theta and phi you get a
matrix as described in
http://users.ece.gatech.edu/~slabaugh/personal/research/euler/euler.pdf
then using procedure like described in this doc extract angles for
Performer
rotation matrix....
Regards
Serge
http://www.vrtainment.de
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From: Performer Newsgroup <csklu_pf++at++yahoo.com>
Date: Fri, 30 Aug 2002 00:24:18 -0700 (PDT)
Subject: Re: [info-performer] limit color values with blending ?
I've played a little bit with the blend functions.
Basically I draw a semitransparent polygon over the
whole scene at the channel near plane after setting
various blend functions. In your case you could use
the glBlendEquation with GL_MAX and set the color of
your polygon to 0.9,0.9,0.9.
--- J=FCrgen Gotschlich <juergen.gotschlich++at++dlr.de>
wrote:
> Hi,
>=20
> I want to clip the values above 0.9, because I don't
> want to darken the
> whole scenery.
> So, I guess I need some blending functionality ?
> --=20
>
_______________________________________________________________________
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> Phone: +49(531)295-3248/2778
> /_/_/_/
> Fax : +49(531)295-2640 =20
> |/ DLR
>=20
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> Aerospace Center
> Institut f=FCr Flugsystemtechnik | Inst. of
> Flight Research
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> Simulation Dep.
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> Lilienthalplatz 7
> D-38108 Braunschweig | D-38108
> Braunschweig, Germany
>
________________________________________________________________________
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From: Jean-Francois Panisset <panisset++at++discreet.com>
Date: Fri, 30 Aug 2002 12:57:46 -0400
Subject: [info-performer] Re: limit color values with blending ?
<200208300900.CAA15797++at++holodeck.engr.sgi.com>info-performer Mailing
List write
s
> From: =?iso-8859-1?Q?J=FCrgen?= Gotschlich <juergen.gotschlich++at++dlr.de>
> Date: Fri, 30 Aug 2002 08:02:03 +0200
> Subject: Re: [info-performer] limit color values with blending ?
>
>Hi,
>
>I want to clip the values above 0.9, because I don't want to darken the
>whole scenery.
>So, I guess I need some blending functionality ?
How about using the gamma tables to do this? Just load a function which
clips any values about 0.9 to 0.9, only has to be done once, no impact
on rendering performance.
JF
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