I have an scene that always crashes POV-Ray 3.01 and 3.02 on AlphaNT,
Alpha/Linux, and Digital Unix.  It is only 4KB (two files) and is at
ftp://arrow.math.twsu.edu/pub/crash

This scene runs just fine on an x86 box and SGI R10000 IRIX64  6.2 IP28.
The crash appears when you hit an object perpendicular to the scan line.  I
compiled pov-win 3.01 for AlphaNT using VC++ to get debug info and I get a
division by zero at line 2209 of HField.c.

2209>>    if((k1<k2 - EPSILON / maxdv) && (k1>0.0))

I'm guessing that maxdv for some reason on Alpha hardware has become zero.
Now the scene does have a pause on an x86 box when it hits the crash spot,
but it will continue with the scan.  I don't have a good debugger on an x86
system right now, so I can't compare how maxdv is being handled differently
on an x86 box.

Anybody have an idea?  What would be the best way to force this scan to
continue on an Alpha?

Mark Arrasmith
arr### [at] mathtwsuedu

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