Yair Kurzion (yair++at++polygon.engr.sgi.com)
Thu, 4 Mar 1999 17:21:31 -0800 (PST)
You found a bug. The ASDGen version you have works OK only when the X and Y
dimensions of the full grid are equal.
I put a new version of ASDGen on my web page:
http://reality.sgi.com/yair/ASDGen/
The new version includes a fix for the bug you found, and other fixes based on
comments from Geoff Levner.
The two files changed are pfdASDGen.c and add_to_pfdu.h (so you'd have to edit
pfdu.h again. sorry).
I couldn't test the fix on your specific case (I don't have the data file), but
I tried it on generic data where X_SIZE != Y_SIZE. This used to produce
incorrect results and now produces correct ones.
Please let me know whether it works for you.
-yair
> Hi pfAll,
>
> I have been intrigued by earlier conversations about the capabilities the
> pfASD node and particularly with doing paging ASD... I am pleased to say
> that for the most part I've been able to work out most of the difficulties
> that I've had by reading the documentation and by looking at code
> snippets... But I have run across a problem in using the pfdASDGen code
> that Yair Kurzion has so generously provided.
> I have modifyed the pagedASD.c code that is included with the ASDGen
> distribution to read my own format of file... this is basically just a flat
> array of elevation data (very simple) and have been successful at
> converting some sizes of files over to the paging ASD format that is
> required here... The dataset that I'm really interested in using is of
> size 2300x1882...
>
> I've converted this file with a tile_size of 200 and just 3 asd_levels
> (for sake of testing) The file loads with no problem, however at one of the
> LODs there appear alot of these really long skinny triangles that run from
> one end of the terrain clear over to the other (see this image for an example)
> http://wasatch.ncsa.uiuc.edu/~rstein/pfASD/2300_1882_grid.jpg
>
> In the very same way, I created a somewhat smaller file of size 1000x1000,
> and the results are as they should be.
> http://wasatch.ncsa.uiuc.edu/~rstein/pfASD/1000_1000_grid.jpg
>
> I should mention that I see these wierd results in both the display code
> that I wrote, and in asdfly... I the results don't seem to be related to
> what data I'm using... I've tried with both real data and fake data that is
> all zeros....
> I would really appreciate some help here... I've included some code that
> is very similar to the pagedASD.c code mentioned above... it is what I'm
> using to convert from my initial file format... after I run this code I
> then run the convasd code as mentioned in the documentation to generate the
> final paged asd files that I've been talking about...
>
> Sincerely,
>
> Robert Stein
>
>
--
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