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Conference bgsdev::open3d

Title:open3d
Notice:Kits on notes 3 and 4; Documents note 223
Moderator:WRKSYS::COULTER
Created:Wed Dec 09 1992
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1306
Total number of notes:5260

1250.0. "Using ig_usesolpath the behavior change" by NETRIX::"[email protected]" (Alberto Galli) Mon Feb 24 1997 05:44

Hi,
i have a problem with a Miata/PS4D40T/NT4.0/SP1 in OpenGl. A customer 
of mine is going to port an application (CAD/CAM) from Intel to 
Alpha NT using our PS4DT boards as graphics cards.
During the porting phase they have experienced that the application
crashes frequently during the spinning phase of a solid model. Further
they have seen that the model presents anomalies, like black triangles
and flashing lines. 
Of course all these are absent on Intel Platform as well Alpha, but 
using AccelPro and 3Daemon (a third party cards that has Alpha driver). 
Looking at the note shipped with the driver, they have tried to set 
the environment variable IG_USESOLPATH, obtaining two different
side-effect:

1. The application has dramatically increased its stability (has to
tested more heavily, but it seems).
2. The model appears perfect on the screen.
3. There are no apparently speed differences between using the apps
with/without this environment.

The questions now are: this variable implements different mechanism from
the firmware one (seemed to us that was similar, and its presence was
due only to implement an easier way to debug applications)?
Is to be intented as debug environment variable or is something different?
What parts are exactly excluded/included/changed setting the variable?

Thank you in advance
Alberto 

[Posted by WWW Notes gateway]
T.RTitleUserPersonal
Name		DateLines
1250.1WRKSYS::CHALTASSomeone chanted eveningMon Feb 24 1997 09:002
    If set to 1, the variable disables all optimizations,
    and may result in dramatically slower performance.
1250.2Please report problems!WRKSYS::DOTYRuss Doty, Graphics and MultimediaMon Feb 24 1997 10:2727
    Please file problem reports against these crashes (and any other
    customer problems)!!!  An open note to everyone reading this conference
    -- we want to know about problems, so that we can fix them.  This means
    that we need enough information to reproduce the problem in our lab
    (unfortunately, "the application crashes frequently during the spinning
    phase of a solid model" isn't quite enough for us to reproduce, debug,
    and fix the problem).  Formal problem reports can be a bit of a
    nuisance, but they are the only way to ensure that a problem gets
    tracked and fixed.
    
    The black triangles sounds like a triangle clipping bug we have seen,
    which is fixed in the next release.
    
    Having said that, try the GSS 4.1 drivers (available at
    http://www.service.digital.com/open3d).  They contain a number of bug
    fixes and may help.
    
    As George mentioned, changing the "solpath" variable can (should!)
    dramatically affect performance.
    
    One thing that we have seen in porting pure Intel apps to Alpha is some
    differences in handling of IEEE floating point exceptions -- our
    porting groups are familiar with the issues.
    
    Thanks,
    Russell Doty
    PowerStorm 4DT Product Mangler
1250.3Sounds like a BUGBGSDEV::COMEFORDThere's coffee in that Nebula !Tue Feb 25 1997 16:4322
setting IG_USESOLPATH to 0 should DRAMATICALLY affect performance
UNLESS both the C code and the assembly/optimized are able
to keep the board fully busy (I know of no
paths where this is true, so it SHOULDn't happen).

You said "The application crashes frequently during..."
By crashes what do you mean? Warnings from 
Dr. Watson/windbg? System crashes (AKA Blue Screen)?
Incorrect pictures?

It sounds like you have a bug. As stated there is
a fix for something similar to what you are
seeing in the V4.1 version of the driver.
Please try that out first. If that doesn't fix
it please report this as a problem. And report it means
we'll need the application, if we can't reproduce
the problem we most certainly can't fix it...


Thanks,
Keith Comeford
PowerStorm 4d40t/50t/60t project lead
1250.4Yes, i will send a reproducerNETRIX::"[email protected]"alberto galliThu Feb 27 1997 12:4310
Yes,
i'm try to arrange the fastest way to send a reproducer and of course
i will open a bug as soon as i receive the reproducer itself (is not
the first time, will be not the last).

Thanks
Alberto


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