HDTenEightyP/NetNews huggingface dataset:
From: robert@slipknot.rain.com (Robert Reed)
Subject: Re: Point inside a triangle
Reply-To: robert@slipknot.rain.com.UUCP (Robert Reed)
Organization: Home Animation Ltd.
Date: Wed, 18 Nov 1992 22:43:50 GMT

In article <1992Nov18.003415.9990@cis.uab.edu> sloan@cis.uab.edu (Kenneth Sloan) writes:
|In article <BxvnnI.90x@slipknot.rain.com> robert@slipknot.rain.com.UUCP (Robert Reed) writes:
|>
|>A trivial modification to the algorithm as I suggested it would correct for
|>this.  If the boundaries of any polygon are to be considered interior, then if
|>a bounding edge is collinear with the test point, it is sufficient to test
|>whether the point is within the interval of the edge.  If it is not, the edge
|>is trivially rejected as before.  If it is, the algorithm can be prematurely
|>terminated with a TRUE result.
|
|Your "trivial modification" is virtually *all* of Professor O'Rourke's
|algorithm!  By the time you make this trivial modification to your
|algorithm, you might just as well throw away your algorithm.

Hardly.  My test is:

	if (t[n].y == t[n+1].y) {
		if (t[n].y == p.y) {
			if (t[n].x < t[n+1].x) {
				l = t[n].x;
				r = t[n+1].x;
			}
			else {
				r = t[n].x;
				l = t[n+1].x;
			}
			if (p.x >= l && p.y <= r)
				return (TRUE);
		}

		/* discard point t[n+1] */
	}

Note that most of this code gets executed only in the rare case that point p is
collinear with a triangle edge which is horizontal.  I forget which one was
"O'Rourke's Algorithm" so I can't address how much of that this is.

Given the explanation of the LeftOfOrOn algorithm, it may be slightly more
efficient in the case of triangles, substituting three cross products for at
most two intersection tests, but it certainly doesn't scale to polygons of more
than three points.
________________________________________________________________________________
Robert Reed			Home Animation Ltd.		503-656-8414
robert@slipknot.rain.com	5686 First Court, West Linn, OR 97068

Outside of a dog, a book is a man's best friend; 
and inside a dog, it's too dark to read.
-- Grouch Marx
________________________________________________________________________________
From: orourke@sophia.smith.edu (Joseph O'Rourke)
Subject: Re: Point inside a triangle
Organization: Smith College, Northampton, MA, US
Date: Thu, 19 Nov 1992 11:56:34 GMT

In article <BxxoH3.BAH@slipknot.rain.com> robert@slipknot.rain.com.UUCP (Robert Reed) writes:
>In article <1992Nov18.003415.9990@cis.uab.edu> sloan@cis.uab.edu (Kenneth Sloan) writes:
>|In article <BxvnnI.90x@slipknot.rain.com> robert@slipknot.rain.com.UUCP (Robert Reed) writes:
>|>
>|>A trivial modification to the algorithm as I suggested it would correct for
>|>this. [...]
>|
>|Your "trivial modification" is virtually *all* of Professor O'Rourke's
>|algorithm!   [...]
>
>Hardly.  My test is: [...]
>Note that most of this code gets executed only in the rare case that point p is
>collinear with a triangle edge which is horizontal.

Why do you only test on horizontal edges?  The point a below is called inside
and the point b outside by the raw ray algorithm.

				   /\
				  a  b
				 /    \
				+------+

In order to classify either both inside or both outside, it seems necessary
to check for collinearity with every edge.  Checking for collinearity 
requires a signed area calculation (or its equivalent).
Xref: sparky comp.graphics:12170 comp.lang.c:16912
From: jfw@ksr.com (John F. Woods)
Newsgroups: comp.graphics,comp.lang.c
Subject: Re: Please Help Me Keep My Job!
Date: 20 Nov 92 15:14:39 EST
Organization: Misanthropes-R-Us

hollasch@kpc.com (Steve Hollasch) writes:
>    My manager has asked me to finish several projects by the end of this
>year, and they're really hard!
>______________________________________________________________________________
>Steve Hollasch                                          Satire & Vitriol, Inc.

I nominate this for the Best Article of the Week.
Newsgroups: comp.graphics
From: spl@pitstop.ucsd.edu (Steve Lamont)
Newsgroups: comp.graphics
Subject: Re: Wanted: FAQ of this group
Date: 18 Nov 1992 22:36:19 GMT
Organization: University of Calif., San Diego/Microscopy and Imaging Resource
NNTP-Posting-Host: pitstop.ucsd.edu

In article <1992Nov18.180112.12551@mtu.edu> yang@mtu.edu (WHY aKs WHY) writes:
>Can anybody give me directions???
>
>PLEASE!

It's down the hall and the first door on your left.  Don't forget to
wash when you're through.

							spl


-- 
Steve Lamont, SciViGuy -- (619) 534-7968 -- spl@szechuan.ucsd.edu
UCSD Microscopy and Imaging Resource/UCSD Med School/La Jolla, CA 92093-0608
"Far out, man"
            - President George Bush, heard in a stump speech on NPR
From: Don_-_Hirschfeld@cup.portal.com
Newsgroups: comp.graphics
Subject: Re: image archive software
Date: Mon, 16 Nov 92 05:11:57 PST
Organization: The Portal System (TM)

You didn't mention what platform you work with. For MSDOS, there is Image
Pals. It creates thumbnail images of all your scans and allows searches of
them by various parameters including description (I believe). It runs under 
Windows.
Newsgroups: comp.graphics
From: dz@cs.brown.edu (Daniel Zalik)
Subject: Re: === Stereo Images ===
Organization: Brown Computer Science Dept.
Date: Mon, 23 Nov 1992 14:52:22 GMT


A kind gentleman in France sent me the name of an anonymous-ftp-site
where there are some stereo images. I have not yet had time to check
it out but here is Eric's message:


+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Hi Daniel,
I've some trouble with the News so I mail you.
You can connect to the following site ftp.ads.com
In VISION-LIST-ARCHIVE/IMAGERY/1991-MOTION-WORKSHOP, you will probably find a
README file. There are stereo images but I don't know exactly where, and a lot
of image sequences. 
Good luck!

----------------------------------------------------------------------------

	Eric CERCLIER
	ETCA/CREA/SP
	16 bis Avenue Prieur de la Cote d'Or
	94114 ARCUEIL Cedex
	FRANCE

	tel : (33) 1 42 31 92 80
	fax : (33) 1 42 31 99 64

	e-mail : cerclier@etca.fr

----------------------------------------------------------------------------
From: sundar@fiber-one.ai.mit.edu (Sundar Narasimhan)
Newsgroups: comp.graphics
Subject: Re: Shortest distance between two line _segments_
Date: 23 Nov 1992 20:37:10 GMT
Organization: MIT Artificial Intelligence Laboratory
Distribution: world
Reply-To: sundar@ai.mit.edu
NNTP-Posting-Host: fiber-one.ai.mit.edu

In article <1992Nov22.112142.24512@sophia.smith.edu>, orourke@sophia.smith.edu (Joseph O'Rourke) writes:
|> In article <By2z4D.How@slipknot.rain.com> robert@slipknot.rain.com.UUCP (Robert Reed) writes:
|> >In article <1992Nov21.000527.21786@zip.eecs.umich.edu> katkere@engin.umich.edu writes:
|> >|
|> >|The problem I am trying to solve is whether two swept spheres intersect.
|> >
|> >Two spheres intersect if the sum of their radii is greater than or equal to the
|> >distance between their centers.
|> 
|> Perhaps what the original poster means by a swept sphere is the set
|> of points obtained by sweeping a sphere along a line segment, which
|> produces a cylinder with spherical endcaps.
I'd think one can compute this using two independent computations.
Let's say L1 L2 are the two lines. 

a. Determine the point P1 on linesegment L1 that is closest to L2.
This can be done very easily if you express the co-ordinates of the
endpoints of L1 in a plane perpendicular to L2, and then find the
point of intersection between this projected segment and a perpendicular 
drawn to it from the origin. (Note that this is a 2-d problem). Let 
this point be Q. Determine the parametric value of Q in [P1 + t(P2-P1)]
and choose one of Q, P1 or P2 depending on whether t is (0,1),<1,>1.

b. Determine the point P2 on linesegment L2 that is closest to L1.
(This is just the same as a. but with the arguments transposed).

Desired distance = dist(P1,P2).
Proof? You must be kidding! :-)
Newsgroups: comp.graphics
From: nmaxwell@carson.u.washington.edu (Nicholas Maxwell)
Subject: What is a widely usable format?
Summary: question: popular format
Keywords: format help question 
Organization: University of Washington, Bothell
Date: Thu, 19 Nov 1992 06:36:08 GMT

I am trying to figure out how to set up an email newsletter that includes
graphics.  It is not necessary to have the graphics embedded in the text: they
could be in a separate file.  Nor would they have to be screen viewable.  I
could ask people to send the graphics directly to their printers and refer to
the printed graphics as they read the articles.

Here's my problem.  I will be soliciting submissions from, and sending the
newsletter to, a large variety of users.  Users will be using Word,
Wordperfect, or a variety of graphics programs such as SigmaPlot, Sygraph,
Harvard Graphics, etc. on PCs, MACs, SUNs, X-terminals etc.  They will be
working with a wide variety of printers.  Furthermore, these are not computer
scientists, and probably a quarter have poor computer skills.

Which graphics format would be best for this situation?   Is there one format
that has a lot of translators, so that if they can't handle the format, they
will be likely to be able to translate the graphics to another format?

Any suggestions would be very appreciated.  Thanks very much.

Nick Maxwell
nmaxwell@u.washington.edu
Organization: Arizona State University
Date: Tuesday, 17 Nov 1992 12:36:15 MST
From: <AGDAV@ASUACAD.BITNET>
Newsgroups: comp.graphics
Subject:    Help!

 I am new to the internet. Can somebody please help me figure
 out how to view some of the pictures on the net on my Mac?

                                     Thanx,
                                    Dave at agdav@acvax.inre.asu.edu
Xref: sparky comp.graphics:12137 comp.lang.c:16870
From: berkery@emmax5crd.ge.com (jack berkery)
Newsgroups: comp.graphics,comp.lang.c
Subject: Re: Please Help Me Keep My Job!
Date: 20 Nov 92 13:27:54 GMT
Reply-To: berkery@emmax5crd.ge.com (jack berkery)
Organization: GE Research Center


Thanks for the laugh Steve, I needed that. It was 10X better than anything ever
posted in rec.humor. But hey, if you find anyone dumb enough to help out please
send their email address to me as well.  ;-)
-------------------------------------------------------------------------------
Jack Berkery, Computer Scientist, GE Research, Schenectady NY
  berkery@crd.ge.com  "The Common Sense Coach"
From: zeller@vax.sonoma.edu (ERIC ZELLER)
Newsgroups: comp.graphics
Subject: macintosh source code library needed..
Date: 21 Nov 92 00:50:00 GMT
Organization: Sonoma State University
News-Software: VAX/VMS VNEWS 1.41

Does anyone know where I can get a library of source code routines that will
display various image files on a 24-bit macintosh display (GIF, TIFF, QRT etc)
I need the source code to modify them to display at the correct location and to
be able to signal the Video Recorder to record the image when done. Currently
the project is in Pascal, but I'll accept any excuse to port the thing to C.
The idea here is speed (currently my routines take 10 minutes to display the
image). Thanx in advance...



'and take my intestines to use for guitar |     EZ Writer
strings, that someone can play as they    |     zeller@sonoma.edu
sing this sad song.' --"As I walked"      |  	P.O. Box 64
		     Garisson Keilor      |	Cotati, CA, 94931-0064
From: pmartz@dsd.es.com (Paul Martz)
Subject: Re: Please Help Me Keep My Job!
Reply-To: pmartz@dsd.es.com (Paul Martz)
Organization: Evans & Sutherland Computer Corp., Salt Lake City, UT
Date: Fri, 20 Nov 92 17:25:23 GMT

In article <1992Nov20.132754.26419@crd.ge.com>, berkery@emmax5crd.ge.com (jack berkery) writes:
> Thanks for the laugh Steve, I needed that. It was 10X better than anything ever
> posted in rec.humor. But hey, if you find anyone dumb enough to help out please
> send their email address to me as well.  ;-)

I don't know what was funnier, Steve's posting or the two followups
which took him seriously...
-- 

   -paul	pmartz@dsd.es.com
		Evans & Sutherland
Newsgroups: comp.graphics
From: craigh@g2syd.genasys.com.au (Craig Hockenberry)
Subject: RFI: PIC32 Format
Organization: Genasys II, Sydney, Australia
Date: Fri, 20 Nov 1992 05:31:48 GMT

One of our salesman came by the other day and started talking about this
wonderful new imaging format called "PIC32". According to his information
it is something that will be specified in future DOD imaging contracts.
He heard about it from someone who had heard it from a friend who knew
someone ...

I haven't ever heard of such a format. If there is anyone "out there" on
the net who has, please drop me an E-Mail with addtional information.

Thanks in advance,
-- 
Craig Hockenberry  |  Genasys II Pty. Ltd.
                   |  13th Level, 33 Berry St., North Sydney, NSW, Australia
                   |  Internet: craigh@g2syd.genasys.com.au
  Testa di Cavolo  |  Latitude/Longitude: -33 50' 00" (S) / 151 12' 00" (E)
From: rcj41604@uxa.cso.uiuc.edu (Huh!?)
Newsgroups: comp.graphics
Subject: Where's the GIF FAQ?
Date: 19 Nov 92 17:59:48 GMT
Article-I.D.: news.Bxz5zq.J3K
Organization: University of Illinois at Urbana

could someone direct me to a ftp site with an extensive GIF FAQ?
I've led a protected life, but I've become curious lately, what
the heck all this stuff called GIF is about...  8-)

   Huh!?  rcj41604@uxa.cso.uiuc.edu
Newsgroups: comp.graphics
From: orourke@sophia.smith.edu (Joseph O'Rourke)
Subject: Re: Polygon (or point) within an arbitrary polygon
Organization: Smith College, Northampton, MA, US
Date: Fri, 20 Nov 1992 02:07:32 GMT

In article <1egv39INNj29@life.ai.mit.edu> sundar@ai.mit.edu writes:
>This problem [polygon in polygon] ([...]) can be solved
>by computing the convolution of the two polygons -- for which linear
>time algorithms exist in the plane. 

The Minkowski sum of two polygons of n and m vertices can have
Omega( n^2 m^2 ) vertices.  Thus if n=m, the size of the convolution
can be proportional to n^4.
	Perhaps you are making some assumptions about the two polygons?
Newsgroups: comp.graphics
From: y1@wilbur.psu.edu (Zhaohui Yang)
Subject: Summery and Question :Re: Wanted: Simple raw-bit image viewer.
Keywords: art competition, complexity, chaos, biology, computation, emergent systems
Organization: Penn State University, Center for Academic Computing
Date: Sat, 21 Nov 92 01:14:19 GMT

Hi, 

thanks for all of you who reply to my question on 8-bit raw image viewer.

Special thanks to following people who reply to me via e-mail:

from ewing@iastate.edu 
From beser@aplcomm.jhuapl.edu 
From mccreary@sword.eng.hou.compaq.com 
From bell@nella4.cc.monash.edu.au 
From GUMLEY@LTP2.GSFC.NASA.GOV 
From warnock@Hypatia.gsfc.nasa.gov 
From bruce@plato.ds.boeing.com 

The program is IMDISP and PICLAB in simtel msdos/graphics.  I prefer the
IMDISP since it can support the SVGA display which makes the image more
smooth.

THe only problem I have is the 3d plot function.  In imdisp it display 
a 3d plot which, the dark area is dark and the bright area is bright.
So if I plot a white rectanglur shape it only show a platform floating
in the air instead of a rectangular column.  I tried the pseducolor 
but the backgroud always mix up with the dark area.

So here comes the question, How can I got a 3d wireframe plot on PC 
of a raw format image?  Is there any program on the net?

Thanks again for all you help.
  




-- 
Zhaohui Yang			<>	 P e n n .  S t a t e
Dept. of Eletrical Engineering	<>
Pennsylvania State Univsity	<>	Tel.# : (814)863-7056
University Park, PA 16802	<>	E-mail: y1@wilbur.psu.edu
Newsgroups: comp.graphics
From: wilson@cs.ucf.edu (tom wilson)
Subject: SportsTracker updates
Organization: University of Central Florida, Orlando
Date: Mon, 23 Nov 1992 19:56:44 GMT

I had two people contact me about the SportsTracker updates I described
a couple of days ago. Apparently you might need to have my address as
wilson@eola.cs.ucf.edu rather than wilson@cs.ucf.edu. The SportsTracker
was down yesterday but I provided updates from Headline News (not as
accurate and no scorers are given). It should be back up today since it
is not a weekend day. Try again tonight and let me know if you will use
it otherwise I'm wasting my time.

Tom
From: lilleyc@cs.man.ac.uk (Chris Lilley)
Newsgroups: comp.graphics
Subject: Re: What is this Grayscaling Formula called ??
Date: 17 Nov 92 02:20:59 GMT
Organization: Dept Computer Science, University of Manchester, U.K.

In article <1duplpINN8h4@uwm.edu> govind@point.cs.uwm.edu (Govind
Seshadri) writes: 

>I was wondering as to what the following formula which obtains the
>corrosponding Grayscale (luminance) of the RGB triplet was called ?
>i.e. what is the name of this formula...

>Grayscale =  0.299 * Red + 0.587 * Green + 0.114 * Blue ;

It is called the NTSC formula.

>What are the origins or the logic behind specifying these values ?

The origin of the formula is the US TV broadcast industry. The formula
gives the value of one of the three components that go to make up an
encoded TV picture.

It also gives you the measured brightness of that RGB colour if you
were to first gamma correct the RGB values by a value of 2.2, then
display it on a 1950s TV set.  Really.

>I have experimented with different values for the same but obviously
>these seem to give me the best results.....

I suggest you continue your experiments. I very much doubt that these
figure - to three decimals! - are the ones that give you the best results.

Remember you must first gamma correct the RGB values so the light
levels are linear. Then try working around the following values

	0.2 R + 0.7 G + 0.1 B

as a basis for experimentation.

If you want to calculate accurate values, get the chromaticities of
your monitor from the manufacturers and work them out. Mail me if you
need to know how to do this. But for a rough greyscale, nothing fancy,
just try experimenting round the values I suggested which are more
typical of modern computer monitors.

--
Chris Lilley
---------------------------------------------------------------------------
Technical Author, ITTI Computer Graphics and Visualisation Training Project
Computer Graphics Unit, Manchester Computing Centre, Manchester, UK
Internet:   lilley@cgu.mcc.ac.uk        Janet:   lilley@uk.ac.mcc.cgu
Voice:      +44 (0)61 275 6095          Fax:     +44 (0)61 275 6040
---------------------------------------------------------------------------
Newsgroups: comp.graphics,comp.graphics.animation,comp.multimedia
From: sh@cypress.com (Steve Haigh/VDSP)
Subject: Fast image display on 24bit Sun
Originator: sh@kahuna
Organization: Cypress Semiconductor/San Jose, CA
Distribution: na
Date: Fri, 20 Nov 1992 23:53:15 GMT

can anyone help me? I have a Sparc2 with cgtwelve (24bit color). I want to
display CCIR601 res images from file (any format, I don't care) as fast
as possible in a movie loop.

If you can help, I will share some of my MPEG2 stuff with you, including
some MPEG2 test sequences.

Please e-mail me or call 408 943 2904. I don't always monitor the net.

Thanks Steve.

Newsgroups: comp.graphics,comp.lang.c
From: rehak@rap.ucar.edu (Nancy Rehak)
Subject: Re: Please Help Me Keep My Job!
Organization: NCAR, Research Application Program
Date: Thu, 19 Nov 1992 23:39:02 GMT

In article <1992Nov19.224135.28721@oz.plymouth.edu> ted@oz.plymouth.edu (Ted Wisniewski) writes:
>In article <1992Nov19.173301.3870@kpc.com> hollasch@kpc.com (Steve Hollasch) writes:
>>
>>    My manager has asked me to finish several projects by the end of this
>>year, and they're really hard!  I told her I could do them, but now I don't
>>know; they're pretty tricky.  I'm sure other people have done stuff like
>>this, so why should I reinvent the wheel?  Why not use the resources of the
>>net?
>
>	Get a clue,  If you told you boss you could do it, I say you should
>do it.  If you cannot fulfill your responsibilities, you do not deserve to
>have your Job!!  There are many qualified people out there who would be
>more than happy to take it.  This is sort of like asking someone else to
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>do you homework for you.  Isn't that like 'plagiarism'?  Sounds to me
 ^^^^^^^^^^^^^^^^^^^^^^^
>like you waited to the last minute.  I hope your boss reads this group!

I believe the highlighted statement is the key here.  See the "Can you program
in C?" message.  :-)

Nancy Rehak
Newsgroups: comp.graphics,comp.lang.c
From: marrou@cs.ucf.edu (Lance R. Marrou)
Subject: Re: Please Help Me Keep My Job!
Organization: University of Central Florida
Date: Thu, 19 Nov 1992 19:51:52 GMT

hollasch@kpc.com (Steve Hollasch) writes:

>    My manager has asked me to finish several projects by the end of this
>year, and they're really hard!  I told her I could do them, but now I don't
>know; they're pretty tricky.  I'm sure other people have done stuff like
>this, so why should I reinvent the wheel?  Why not use the resources of the
>net?
(some text deleted)

Perhaps we should let you lose your job and let someone who either knows what
they are doing or doesn't open his/her mouth as wide take over! :)

--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Lance R. Marrou
   Work   - Marrou@IST.UCF.edu
   School - Marrou@Eola.cs.UCF.edu
Newsgroups: comp.graphics
From: sloan@cis.uab.edu (Kenneth Sloan)
Subject: Re: Point inside a triangle
Organization: CIS, University of Alabama at Birmingham
Date: Tue, 17 Nov 1992 04:17:10 GMT

In article <1e9k0cINNc0q@uniwa.uwa.edu.au> watson@maths.uwa.oz.au (David Watson) writes:
>watson@maths.uwa.oz.au (David Watson) writes:
>
>
>and if b0 == 0 => (x1 == x2 && x1 == x3 && y1 == y2 && y1 == y3)

I would be fascinated to see a proof of this...



-- 
Kenneth Sloan                   Computer and Information Sciences
sloan@cis.uab.edu               University of Alabama at Birmingham
(205) 934-2213                  115A Campbell Hall, UAB Station 
(205) 934-5473 FAX              Birmingham, AL 35294-1170
Newsgroups: comp.graphics,comp.graphics.visualization,comp.graphics.explorer,comp.sys.sgi,comp.graphics.animation,comp.windows.x.intrinsics