The Persistence of Vision Raytracer (POV-Ray).
This is the legacy Bug Tracking System for the POV-Ray project. Bugs listed here are being migrated to our github issue tracker. Please refer to that for new reports or updates to existing ones on this system.
Opened by Grimbert Jérôme - 2012-06-25
Last edited by William F Pokorny - 2017-01-23
FS#246 - Regression on scale limit between 3.7 and previous releases
From Thomas de Groot
Using the following code for a (sky) sphere in a scene, with light source well outside the sphere;
works correctly until the above scale value. Use a value of >=100*10e4 and the sphere becomes black.
#version 3.7;
global_settings{ assumed_gamma 1.0 }
#declare T_sky =
texture {
pigment {
gradient y
pigment_map {
[0.0 srgb <1.0,0.7,0.6>*1 transmit 0.5]
[1.0 srgb <0.8,0.1,0.0>*1 transmit 0.5]
}
}
finish {
emission 0.9
diffuse 0.0
}
}
#declare T_cosmos =
texture {
pigment {
color rgbt <0,0,0,1>
}
finish {
ambient 0.0
diffuse 0.0
}
}
sphere {
<0,0,0>,1
texture {T_sky}
interior_texture {T_cosmos}
no_shadow
no_reflection
inverse
scale 99.9*10e4
}
Working with windows version of POV-Ray and Win7 x64
Is this normal for version 3.7 RC5? I seem to remember that with lower
versions of POV-Ray on could go at least to 10e6. Especially with the
Ringworld scenes back in 2010 the scales used where much larger without
any black out.
I can indeed confirm that the Ringworld scene does not render correctly anymore, with identical black out.
Confirmed with Linux 3.7RC6
Seems related to the values in configbackend.h (source/backend/) of SMALL_TOLERANCE & MAX_DISTANCE
Additional comment: unable to duplicate the 3.6.1 reported behavior:
With my 3.6.1 (fresh compilation from source), the picture is also full black for a scale of 100.0*10e4
I will check a 3.5 later.
Well, it's easier to compile 3.1 than 3.5
With 3.1, I got the same behaviour as with 3.6.1 & 3.7RC6 : light red at 99.9*10e4, full black at 100.0*10e4
On 3.1, the difference of render between 99.9*10e4 and 100.0*10e4 is:
Versus (100):
There is no more transmitted ray for the 100.0*10e4
This is for the Unix code. Maybe the Windows distribution used a bigger MAX_DISTANCE (or Max_Distance, it was spelled differently in previous version; but was still 1.0e7 on Unix since 3.1)
POVWIN hasn't used a different MAX_DISTANCE to that in the main source in any build that I can think of, and a look through the old source and revision history seems to confirm that.
For a while (Feb through May 2005) MAX_DISTANCE was 1.0e+10 and SMALL_TOLERANCE 1.0e-6, but apart from that it's had the old values for as long as I can remember.
Now tracked on github as issue #215.