When I render the following scene as a 512x384 image with the parameter +k
of 0.54 or 0.86, or probably several other values, UVPOV 5.2 crashes with
the error "UVPOV caused an invalid page fault in module UVPOV.EXE at
015f:00442445." while rendering line 147 of the image.  However, if any of
the lines in the photons block in the global_settings is commented out, or
if a value for +k less than 0.54 is used, this error does not occur.

#include "textures.inc"

#declare phd = 1;

global_settings{
    photons{
      gather 20, 100
      radius 0.1*phd, 2, 0.1*phd
      autostop 0
      jitter .4
      expand_thresholds 0.2, 40
    }
}
camera{
    location <17,10,0>
    look_at <0,0,0>
}

light_source{ <27,0,0> rgb 1 }

box{ <-1,-1,-1>,<0,1,1>
    pigment{rgb 1}
    finish{ambient .2 diffuse .5}
}

intersection
{
    sphere{ <1,0,0>, 1.75 }
    sphere{ <-1,0,0>, 1.75 }
    texture{ Glass2 }
    interior{ior 1.5}
    translate x*(10*sin(clock*2*pi))
    photons{
      refraction on
      separation 0.02*phd
    }
}

--
main(i,_){for(!_||(--i,main(i+2,i["FHhhTBFHdhTBFBQT\2TBF&]zRF$hh*:FHhh+&FBIs
bDF"]));i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_^=_,"\n")),_/=2);} /*-
Mark -*/

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On Wed, 18 Aug 1999 01:39:03 -0400, Mark Wagner wrote:
>When I render the following scene as a 512x384 image with the parameter +k
>of 0.54 or 0.86, or probably several other values, UVPOV 5.2 crashes with
>the error "UVPOV caused an invalid page fault in module UVPOV.EXE at
>015f:00442445." while rendering line 147 of the image.  However, if any of
>the lines in the photons block in the global_settings is commented out, or
>if a value for +k less than 0.54 is used, this error does not occur.

It appears that photonOptions.numPhotons is zero when it goes to gather 
photons.  I've seen this once, too, but I attributed it to my inability to
write a proper scene file.  I think this means that there's nothing for 
your photons to hit, so they fly off into space and are never recorded.
Obviously it's a bug in UVPOV that this causes it to crash, but it's also 
a bug in your scene file.  Replacing your box with 

plane { x, -5 
  texture {
    pigment {color rgb 1}
    finish {ambient .2 diffuse .5}
  }
}


results in a scene that renders just fine.  Hopefully Nathan can come
up with a brilliant fix that resolves the crash problem as well.

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Yes.  This was a bug.  The latest version shouldn't have this bug anymore.
As Ron pointed out, the problem is when the system expects photons but none
were stored on the surfaces of objects.  I've added a variety of checks
for this, so it should be fixed.

-Nathan

Mark Wagner wrote:
> 
> When I render the following scene as a 512x384 image with the parameter +k
> of 0.54 or 0.86, or probably several other values, UVPOV 5.2 crashes with
> the error "UVPOV caused an invalid page fault in module UVPOV.EXE at
> 015f:00442445." while rendering line 147 of the image.  However, if any of
> the lines in the photons block in the global_settings is commented out, or
> if a value for +k less than 0.54 is used, this error does not occur.
>

Post a reply to this message

Nathan Kopp wrote in message <37BB74D5.A01ACDB0@Kopp.com>...
>Yes.  This was a bug.  The latest version shouldn't have this bug anymore.
>As Ron pointed out, the problem is when the system expects photons but none
>were stored on the surfaces of objects.  I've added a variety of checks
>for this, so it should be fixed.


Yes, I see why that occurs.  The lens I am firing photons at is behind the
box I am focusing the photons on, so none of the photons fired at the lens
arrives anywhere.  I'll upgrade my copy of UVPov ASAP.

Thanks,
Mark

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