HDTenEightyP/NetNews huggingface dataset:
From: erich@eye.com (Eric Haines)
Newsgroups: comp.graphics,sci.image.processing
Subject: Creating texture tiles
Date: Fri, 4 Sep 92 14:34:04 GMT
Summary: how do they do that?
Distribution: world
Organization: 3D/EYE, Inc.  Ithaca, NY

How are seamless tiles of a texture created?  Various companies sell texture
libraries that include texture tiles that can be repeated and no seams are
visible.  For example, given a scanned patch of grass, how can this be
processed so that the resulting image can be repeated across a surface and not
have the image edges noticeable?

I haven't seen much on this in the literature (which hopefully means I'm not
looking at the right literature, eh?).  This question is easily answered if
you're generating synthetic textures - you simply attach the edges
(topologically, a torus) so that the thing is generated seamlessly.  But given
a scanned texture you don't have this ability.  Simply blurring the edges
helps a little, but you can see the blur.  I can imagine you might use Burt's
pyramidal parametrics (I played around with "pyrmask" in the Utah Raster
Toolkit a bit, without great results) or doing some sort of pair of
convolutions, but this is where my image processing knowledge tends to give
out.

Post, or write me and I'll summarize.  Any ideas or explanations of real life
experiences appreciated,

Eric
Newsgroups: comp.graphics,comp.graphics.explorer,comp.graphics.visualization
From: vthrc@brolga.cc.uq.oz.au (Danny Thomas)
Subject: (Q) calculating spatial density
Keywords: spatial density algorithm statistics
Organization: Prentice Centre, University of Queensland
Date: Mon, 14 Sep 1992 10:42:27 GMT


I've got a complex 2D shape with a set of points in it and need to 
generate a map of density of those points. I'm sure this topic must be 
well-explored but one complication is that there are holes in the shape 
too. 
    The relatively small size of this data-set does however allow points 
to be snapped to a fine pixel grid and areas calculated by pixel-
counting. A simple approach would be to:
1. count the number of data points in a circular radius around each grid-
point
2. calculate the area of holes in that radius by counting hole-pixels
3. subtract that area from that of the circle
4. divide the number of data-points by the non-hole area to give 
   a measure of the density

but I would be interested to learn of "more analytical" algorithms that 
don't depend on quantizing coordinates. It would also be interesting to 
read about techniques that can handle arbitrary weighting functions. eg 
if an inverse square weighting is applied to distances from a grid point 
to each data-point, what do you do when that vector crosses over a hole? 
Perhaps more accurately, how could you estimate a contribution from the 
points that would exist if that hole wasn't there?


The final step of converting a density grid into a contour map should be 
solvable with other tools we have.

PS I've already received a pointer to the bivar module from avs.ncsc.org, 
and apart from the fact it doesn't seem to account for holes (or edges), 
we don't have AVS. We only have Macs & PCs but are planning on an SGI 
Indigo XS24 soon, which means we are particularly interested in Explorer 
(& Khoros?).

because of server problems I'd appreciate an email copy of any replies 
posted to net-news. It might be worth reducing the number of groups any 
reply is sent to.

cheers,
X500: @c=AU [I'm about to update VTHRC entries, soon...]
       @o=University of Queensland
        @ou=Physiology and Pharmacology Department
         @ou=Vision Touch and Hearing
          @cn=Danny Thomas
           @rfc822Mailbox=vthrc@cc.uq.oz.au
                          ^^^^^^^^^^^^^^^^^  <- return address


PS  & apologies for cross-posting, you'd think this a basic GIS function.
From: niwr@pfbs.philips.se (Niklas Wretman)
Newsgroups: comp.graphics
Subject: Resolution when conv BMP -> TIFF
Date: 10 Sep 92 14:06:56 GMT
Organization: Digital Equipment BCFI AB, Sweden

Hi,

Does anybody know how to get (calculate) the XResolution
and YResolution tag when converting Windows BMP images to TIFF??


/Niklas Wretman (niwr@pfbs.philips.se)


--
|---------------------------------------------------------|
|   Niklas "Nicko" Wretman,  Digital Equipment BCFI AB    |
|    phone: +46-8-759 4790, facsimile: +46-8-739 8676     |
|   email: niwr@pfbs.philips.se or d87-nwr@nada.kth.se    |
Xref: sparky comp.graphics:9549 comp.windows.x.pex:541 comp.unix.aix:9484 alt.graphics:339
From: pfuetz@igd.fhg.de (Matthias Pfuetzner)
Newsgroups: comp.graphics,comp.windows.x.pex,comp.unix.aix,alt.graphics
Subject: Re: IBM's graPHIGS package, problem with GPNBS, any hint?
Date: 9 Sep 92 11:33:01 GMT
Reply-To: pfuetz@igd.fhg.de (Matthias Pfuetzner)
Followup-To: poster
Organization: Zentrum fuer Graphische Datenverarbeitung, Darmstadt, FRG

Hi again!

In article <Bu2BFs.Lzw@well.sf.ca.us> levine@well.sf.ca.us (Ron Levine) writes:

>I'm not sure this is your problem, but it's worth checking:
>
>I haven't worked directly with graPHIGS, but a couple of years ago, when
>porting a graPHIGS demo application to DEC PHIGS, I discovered that for the
>RATIONAL B-spline case, graPHIGS expects DIFFERENT data from DEC PHIGS,
>SunPHIGS, and most of the other implementations.  Namely, for the coordinate
>4-tuple for the weighted control points, graPHIGS expects the application to
>pass (x,y,z,w), while the other implementations expect (xw,yw,zw,w).

As schultz@schultz.kgn.ibm.com (schultz) writes in <1992Sep04.202508.35044@watson.ibm.com>:

>This is correct, although if the app passes the homogenous form, it usually
>results in wierd-looking results instead of a blank screen.  I guess it depends
>on how big w is.

It was worth checking, because it would have caused new questions, but it is
right, still nothing can be seen. My weights are simply 1.0 and cos( 45 deg )
= 0.70710676908493042. I need them for getting real circles and pieces of
circles, for modeling tubes.

But perhaps someone can help me by answering the following question:

Are there any attributes in graPHIGS for non-uniform B-spline surfaces that
apply only to them and that do not exist in PEX-SI? Perhaps I have overseen
things like that that might cause the surface to be drawn white on white or
something like that. I did check the manual pages and found nothing
appropriate, but who knows...?

Sincerly,
        Matthias
-- 
    Matthias Pfuetzner  |  @work:  +49 6151 155-150  | @home: +49 6151 75717
    6100 Darmstadt, FRG | ZGDV, Wilhelminenstrasse 7 | Lichtenbergstrasse 73
      pfuetzner@igd.fhg.de, pfuetzner@zgdvda.UUCP    |  Keith Packard said:
      R5 is different from R4. That's why we changed the release number :-)
From: mbc@po.CWRU.Edu (Michael B. Comet)
Newsgroups: comp.graphics
Subject: 2 color GIF decoding error!
Date: 10 Sep 92 02:08:04 GMT
Reply-To: mbc@po.CWRU.Edu (Michael B. Comet)
Organization: Case Western Reserve University, Cleveland, OH (USA)
NNTP-Posting-Host: slc4.ins.cwru.edu


	Help!

	I am using the assembly GIF decoder module from Steve Rimmers
book "Bitmapped Graphics" and seem to have run into a bug!

	Everthing is fine, but for some reason when I view a decoded GIF
if EXACTLY 2 COLORS the image is really messed up.  It looks like it is
getting every other pixel and or line.  

	If you have gotten this to work PLEASE let me know,,,,or if you
know anything about something special with 2 color GIF PLEASSE PLEASE
PLEASE send e-mail!!!!!!!!
	
	Thanks,......please send all replies via e-mail to the address
below rather than reposting here..  thanks,

			Mike Comet
			mbc@po.CWRU.Edu
From: johnson@charming.nrtc.northrop.com (Greg Johnson)
Newsgroups: comp.graphics
Subject: help needed finding view factor pgm
Date: 5 Sep 92 05:12:05 GMT
Followup-To: johnson@nrtc.northrop.com

Is there an ftp'able program to compute view factors?

What I need is the following:  say we have is a 3-D space defined
by a collection of polygons.  For each polygon, what fraction of
diffuse light emanating from it hits each other polygon?  The computation
would probably have to consider the distance between two polygons,
their sizes, the angle between the planes of the two polygons, and any
intervening objects that partially or totally block the polygons from each
other.

Any help or pointers would be greatly appreciated!

Greg Johnson
johnson@nrtc.northrop.com
Xref: sparky comp.graphics:9581 comp.lang.postscript:4650
From: lewin@brokaw.lcs.mit.edu (Jonathan Lewin)
Newsgroups: comp.graphics,comp.lang.postscript
Subject: postscript separations
Date: 10 Sep 92 01:21:28 GMT
Article-I.D.: mintaka.1992Sep10.012128.16339
Organization: MIT Laboratory for Computer Science


Hi, I'm the author of a scientific textbook, and I did all the figures (some
600) in Micrografx Designer 3.0, and the publishers can't seem to print 
them properly I'm desperate -- any help at all is really appreciated.
 
The problem is in generating color separations on Micrografx Designer 3.0?
When Designer DRW files are used to generate 4-color (plus 1 spot)
separations as Postscript EPS files, bit mapped patterns are lost.
When the file is printed on typesetting equipment, what appears in the region
that should contain the bit mapped is a pattern of large dots. The same
problem occurs irrespective of which bit mapped pattern is being used.
The files can be printed perfectly well on lasers in black and white or
in color, so the problem appears to be specific to the generation of
separations. One possibility is that the 4 screens are being
rotated with respect to another in the region of the bit map (the angles for
the separation are left at the default values when the postscript files are
generated, since otherwise the rest of the drawing will not reproduce
properly when printed). Is there any way within Designer to generate
postscript files for 4-color separations that will allow bit maps to print
properly, or is there any other program that could take Designer postscript
output and manipulate it to generate effective separations?
Newsgroups: comp.graphics,cis.graphics
From: ebert@hockey.cis.ohio-state.edu (David S. Ebert)
Subject: Siggraph '92 Course 23 source code available
Organization: The Ohio State University Dept of Computer & Information Science
Date: Wed, 9 Sep 1992 20:18:34 GMT

The source code from the notes of Siggraph '92 Course 23 (Procedural
Modeling and Rendering Techniques) are now available for anonymous ftp
from archive.cis.ohio-state.edu in directory pub/siggraph92. This
directory contains a shell archive file called siggraph92_C23.shar .
Without a copy of the course notes, these files may not make sense. If
you have any problems with the information in this archive, please
contact me or the author of the individual file.



-- 
--  Dr. David S. Ebert,   Department of Computer and Information Science  -----
---  The Ohio State University; 2036 Neil Ave. Columbus OH USA 43210-1277  ----
-- ebert@cis.ohio-state.edu or ..!{att,pyramid,killer}!cis.ohio-state.edu!ebert
-------------------------------------------------------------------------------
Newsgroups: comp.graphics,comp.sys.ibm.pc.hardware
From: mch@regent.e-technik.tu-muenchen.dbp.de (Michael Hermann)
Subject: Re: 486 external cache
Organization: Technical University of Munich, Germany
Date: Wed, 9 Sep 1992 07:59:04 GMT

<REE700A@MAINE.MAINE.EDU> writes:

>...
>  Before you scoff at that 8K cache, it is NOT DIRECT MAPPED, WRITE THROUGH!
>That Intel cache is a 4-way set associative, write back cache and is

According to Intel literature the onchip-cache is 4-way write through.
Simulations have shown, that at full bus speed (achievable by an
external cache) the write-through approach is even a small bit faster
than a write-back cache.

>roughly equivalent to the 64K external caches of most Motherboards!  Of
>course, a 128K, 2-way... cache is roughly equivalent to the 256K systems
>of many current motherboards.  You can not judge a cache by size alone.

In fact you cannot judge it by size alone. And you cannot judge it by
associativity and size alone. Just what about line size, for example.
To my (limited) experience line size and cycles needed to refill a line
(can execution start before line is filled or must the CPU wait) is
much more important as associativity. Frankly I don't dare to give 
any formula that holds for any application to give cache performance.

The big gain of the internal cache comes from fast communication on the
chip. No external cache of any size can achieve this. And if the internal
cache can achieve a 90% hit-rate, there is not that much room for further
improvement by external caches.

>...
>   Fevrier - Replace your crystal (50 or 100 MHz) with a 40 or 80 MHz
>one.  Your CPU will be slower than at 50MHz but faster than 33 MHz and
>the added 5nS per cycle will make that cache zero wait state.  Save the
>original crystal for when you upgrade the cache to < 20 nS!

This amazes me. I thought, the number of waitstates is hardwired into
some state machine that simply "knows" that the memory will deliver data
within the n-th cycle. Of course, if you slow down the clock or buy 
faster RAMs the data will eventually be valid one cycle earlier. But how
does the system distinguish valid data from invalid data? That is, how
is it supposed to eliminate one wait state without beeing told so?

>    Jeff Andle

Michael Hermann
Xref: sparky comp.graphics:9503 comp.windows.x:16304
From: azhao@cs.arizona.edu (Qiang Alex Zhao)
Newsgroups: comp.graphics,comp.windows.x
Subject: Spectrum RGB values?
Keywords: spectrum RGB
Date: 8 Sep 92 03:23:34 GMT
Followup-To: comp.graphics
Organization: Computer Science Dept, Univ of Arizona, Tucson

Hi,

I need a list of RGB values that can approximate a spectrum. Any idea?
Thanks.

-- 
= Qiang Alex Zhao		   Computer Science Department
  azhao@cs.arizona.edu             University of Arizona
  (602) 621-1815                   Tucson, AZ 85721
From: mengel@dcdmwm.fnal.gov (Marc W. Mengel)
Newsgroups: comp.graphics
Subject: Re: Question: difference in viewed and printed images
Date: 8 Sep 92 17:11:30 GMT

lilleyc@cs.man.ac.uk (Chris Lilley) writes:

>In article <mack.715549997@deci> mack@deci.cs.umn.edu (Dan Mack)
>writes:

>>In <1565@eagle.ukc.ac.uk> sc7@ukc.ac.uk (S.Chan) writes:

>>>I have printed some decompressed images on hardcopy and they don't
>>>look quite the same as that is shown on a monitor, specifically
>>>the effects of noise, sharpness and blocking effects. (a 2400dpi
>>>printer was used to print the 256-level grey scale images)
>                                ^^^^^^^^^^^^^^^^^^^^
>>>I suppose there is a great difference between viewing pictures on
>>>screen and on paper. 

an important other possibility is that your printer has "fat" black
pixels, i.e. the black pixels overlap into the adjacent white pixels.
This makes your dark areas darker; i.e. a checkerboard pattern does
not give you a 50% grey, but somewhat darker.  Often dithering to
a 1/2 printer resolution black and white image and printing 2x2 pixel
white and black dots gets rid of enough of this fuzz-over to make the
grey tones look a lot better.  Unless of course anyone knows a good
dithering/halftoning algorithm to cover for "fat" dark pixels...

Also you should use at least a 16x16 dither matrix, or appropriate
halftoning, to get anywhere near a 256 greyscale image on a black/white
device.
-------
Marc Mengel
mengel@fnal.fnal.gov
From: snoswell@sirius.ucs.adelaide.edu.au (Michael Snoswell)
Newsgroups: comp.graphics
Subject: Re: Virtual reality lib for 386?
Date: 11 Sep 92 10:25:47 GMT
Organization: The University of Adelaide
NNTP-Posting-Host: sirius.itd.adelaide.edu.au

hole@phoenix.oulu.fi (Jari K{hk|nen) writes:


>   There was an announcement of Virtual Reality library for 386 in 
>   comp.graphics about 4-5 months ago. I've checked my famous ftp-sites,
>   but I cannot find it. Was it vr386 or something like that? Anyway, if
>   somebody could tell where to get it, I would be very pleased. Thank you.

Rend386 available from sunee.uwaterloo.cu
-- 
----------------------------------------------------------------------------
  Michael Snoswell                         snoswell@sirius.ucs.adelaide.edu.au  
  Vision Systems Limited                   +61 8 343 0610 <- note the change
  South Australia                          "Profound and witty quote"
Newsgroups: comp.graphics
From: jgibson@alias.com (John Gibson)
Subject: Re: 3-D Studio --> Alias
Organization: Alias Research, Inc., Toronto ON Canada
Date: Mon, 14 Sep 1992 17:18:22 GMT

In <marrou.716215668@eola.cs.ucf.edu> marrou@cs.ucf.edu (Lance R. Marrou) writes:

>kpm8447@tesla.njit.edu writes:

>>I recently took a class on Autodesk 3-D studio (V. 1) and this semester
>>I'm taking a class on Alias (V. 3) (On a Silicon Graphics Iris  Workstation)
>>Is there a way to port objects/scenes/whatever from 3-d studio to Alias?
>>I'm sure it can be done w/ .dxf formats but I was wondering if there were
>>any other ways.
>> - Thanks in advance
>> - Kirk

>Unless you write (or for some bizarre chance, find) your own conversion
>program, no.  Autodesk and Alias only correspond through .dxf.  

Geometry data can be transferred between Alias products and AutoCAD using
IGES files as well as DXF.

            __   __      
             |__/ _)
          _  | /  _     
         /  _|/| \ \
        (  J__G\  ` )
cheers   \__/   \__/
--
            __   __      
             |__/ _)
          _  | /  _     
         /  _|/| \ \
Newsgroups: comp.graphics,comp.graphics.visualization,comp.graphics.avs,comp.graphics.explorer
From: avs@doppler.ncsc.org (Terry Myerson)
Subject: Vol Vis Workshop Data
Organization: North Carolina Supercomputing Center
Date: Thu, 10 Sep 1992 13:24:34 GMT

Hi folks -

Several people have submitted sample data sets for the Boston Workshop on Volume
Visualization.  These data sets are public domain - but please attach credits
wherever the data is used.  Feel free to explore any visualization techniques 
that you find appropriate with them, including Volume Visualization...

The data is available through anonymous ftp to 128.109.178.23 ( avs.ncsc.org ).
cd to the ~ftp/VolVis92 directory for more information on the conference and 
the data set directories.

Enjoy -

Terry

---
Terry Myerson
International AVS Center
North Carolina Supercomputing Center
tvv@ncsc.org


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

Data Description :	Tropospheric ozone, temperature, and geopotential height
			for several time steps
Submitter	 :	Lloyd Treinish, TJ Watson Research Center
Format		 :	CDF
Directory	 :	~ftp/VolVis92/troposphere

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

Data Description :	Simulated electron density around the C60 bucky ball for 
			one time step
Submitter	 :	Charles Brabec, North Carolina State University
Format		 :	HDF
Directory	 :	~ftp/VolVis92/c60
	
----------------------------------------------------------------------------

Data Description :	Finite element model of a sedimentary basin for several 
			time steps
Submitter	 :	Nancy Saltzman, University of North Carolina - Chapel Hill
Format		 :	AVS UCD
Directory	 :	~ftp/VolVis92/basin

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

Data Description :	Multivariate data within a canine dog heart for several 
			time steps
Submitter	 :	Tom Palmer, North Carolina Supercomputing Center, Cray Research
Format		 :	Raw data
Directory 	 : 	~ftp/VolVis92/canine-bioelectic

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

Data Description :      Simulated acid deposition over the eastern U.S. for several
			time steps
Submitter        :      Chris Landreth, North Carolina Supercomputing Center
Format           :      Raw data & AVS geom for reference map
Directory        :      ~ftp/VolVis92/radm

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

Data Description :      Space Shuttle Launch Vehicle Simulation
Submitter        :      Sam Uselton, CSC
Format           :      PLOT3D
Directory        :      ~ftp/VolVis92/shuttle

----------------------------------------------------------------------------
Newsgroups: comp.graphics
From: cb@wixer.cactus.org (Cyberspace Buddha)
Subject: Re: X-rated GIFs
Keywords: GIFs
Organization: Real/Time Communications
Date: Mon, 14 Sep 92 04:55:28 GMT

In article <BuFo31.2EA@news.cso.uiuc.edu> rmihlfri@ux4.cso.uiuc.edu (Robert J Mihlfried) writes:
>Does anyone know the internet address of an anonymous FTP site where you 
>can get high quality aesthetically pleasing X-Rated (or NC-17) GIF files?
>Any advice will be warmly welcomed.

wustl.wuarchive.edu has at least a few NC-17 pix...
I usually drop by there occasionally to find nifty non-sexual
weirdness.  I think my favorite acquisition from there was called
forehead.gif...

laters,
cb

Newsgroups: comp.graphics
From: meglan@mayo.edu (Dwight Meglan)
Subject: Convert Precision Visuals DI3000 to X
Followup-To: comp.graphics
Organization: Orthopedic Biomechanics/ Mayo Clinic
Date: Thu, 10 Sep 92 12:49:45 GMT

I have a number of programs that were developed several years ago
using Precision Visuals DI3000 graphics package. I would like convert
these as quickly as possible to use X. I don't want to mess with the
user interface, which is command line driven and ugly, nor do I want
to do anything fancy with windows- I just want to put up a single 
graphics window in place of the DI3000 screen, draw to it, and print
out the result.

My question is: Has anyone done this already and if so could they share
their experiences ? Ideally I would like to find a way of just substituting
routines using X calls for the DI3000 routines. I presume that I will have
to put together a number of small routines that have the functional 
equivalent of the DI3000 routines.


Thanks in advance for any and all help.

dwight
From: kpm8447@tesla.njit.edu
Newsgroups: comp.graphics
Subject: 24X .gif viewers
Date: 14 Sep 92 13:26:09 GMT
Organization: New Jersey Institute of Technology

Does anyone know the latest versions of vpic and gds and any other
gif viewers for dos?  I have vpic 5.0 and gds 1.1 (not registered)
I'm looking for viewers that currently support Diamond Speedstar 24X (windows
accelerator card)  The normal Speedstar 24 drivers don't work with vpic 5.0
 - Kirk
Newsgroups: comp.graphics
From: pnarayan@cs.tamu.edu (P S Narayan)
Subject: Basics
Organization: Computer Science Department, Texas A&M University
Distribution: usa
Date: Mon, 14 Sep 1992 02:40:54 GMT

Thanks
Narayan
pnarayan@cs.tamu.edu
From: ahern@sage.cc.purdue.edu (Sean Ahern)
Newsgroups: comp.graphics
Subject: Re: GIF 87a/89a
Keywords: GIF
Date: 6 Sep 92 02:13:17 GMT
Organization: Purdue University

In <18ailqINNi59@network.ucsd.edu> spl@alex.uucp (Steve Lamont) writes:

>In article <1992Sep4.130918.10969@cucs5.cs.cuhk.hk> ckchiu@cucs11.cs.cuhk.hk (Chiu Chong-kan) writes:
>>Can anyone tell me what is the difference between GIF87a & GIF89a ?

>Two.

>:-)

No, 0x000020.   B-)               (As if G is hex....)
Newsgroups: comp.graphics
From: prasad@m.cs.uiuc.edu (Ganesh K)
Subject: CCITT standard test image documents
Summary: standard CCITT test images
Keywords: CCITT images
Organization: University of Illinois, Dept. of Comp. Sci., Urbana, IL
Date: Tue, 8 Sep 1992 22:28:07 GMT


	I would like to have the 8 standard CCITT test document
	images used for testing various image compression algorithms.

	Can somebody, let me know where I can find them ???

	--ganesh


Newsgroups: comp.graphics