Package: povray
Version: 1:3.6.1-12+b1
Severity: normal
Hello,
I found a bug in the functionality of povray, that is in the way it treats
geometrical properties. I think that it is a problem of povray itself and not
of the debian package, but as the version I use is "unofficial" (as it says in
the version information), I file the bug against the debian package:
I am trying to rotate a polygon such that it intersects a cube at three
corners. I found that the rotation about an axis (x+y) does not rotate as
expected. The true rotation axis seems to have an offset of about 7 degrees,
but I have not figured out in what direction it might go. Please see the
following example:
------- example code -----
# include "colors.inc"
global_settings { ambient_light White }
background { color White }
camera {
# declare phi = 135 * pi/180;
# declare theta = 45 * pi/180;
# declare dist = 10;
location <dist*cos(phi)*sin(theta), dist*cos(theta), dist*sin(phi)*sin(theta)>
look_at <0,0,0>
}
// make a cubic frame
union {
cylinder { <-1,-1,-1>, < 1,-1,-1>, 0.05 }
cylinder { < 1,-1,-1>, < 1, 1,-1>, 0.05 }
cylinder { < 1, 1,-1>, <-1, 1,-1>, 0.05 }
cylinder { <-1, 1,-1>, <-1,-1,-1>, 0.05 }
cylinder { <-1,-1, 1>, < 1,-1, 1>, 0.05 }
cylinder { < 1,-1, 1>, < 1, 1, 1>, 0.05 }
cylinder { < 1, 1, 1>, <-1, 1, 1>, 0.05 }
cylinder { <-1, 1, 1>, <-1,-1, 1>, 0.05 }
cylinder { <-1,-1,-1>, <-1,-1, 1>, 0.05 }
cylinder { < 1,-1,-1>, < 1,-1, 1>, 0.05 }
cylinder { < 1, 1,-1>, < 1, 1, 1>, 0.05 }
cylinder { <-1, 1,-1>, <-1, 1, 1>, 0.05 }
material { texture { pigment { Blue transmit 0.3 } } }
}
// visualize the problematic rotation axis
cylinder { <-2,-2,0>, <2,2,0>, 0.01 }
polygon { // the cutting plane
4,
// start with a square in x-y plane
<-2,-2,0>, <2,-2,0>, <2,2,0>, <-2,2,0>
// then rotate by 45 deg: OK
rotate 45 * z
// then rotate up
rotate atan(-sqrt(2))*180/pi * (x+y)/sqrt(2) // this is the problematic
rotation
// and shift such that the polygon goes through the corners
translate 0.5 * (-x+z)
texture {
pigment { Yellow transmit 0.3 }
finish { ambient 1 diffuse 0 }
}
}
--------- end of example code --------------
-- System Information:
Debian Release: 6.0.1
APT prefers stable
APT policy: (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 2.6.32-5-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Versions of packages povray depends on:
ii libc6 2.11.2-10 Embedded GNU C Library: Shared lib
ii libgcc1 1:4.4.5-8 GCC support library
ii libjpeg62 6b1-1 The Independent JPEG Group's JPEG
ii libpng12-0 1.2.44-1 PNG library - runtime
ii libstdc++6 4.4.5-8 The GNU Standard C++ Library v3
ii libtiff4 3.9.4-5 Tag Image File Format (TIFF) libra
ii libx11-6 2:1.3.3-4 X11 client-side library
ii zlib1g 1:1.2.3.4.dfsg-3 compression library - runtime
Versions of packages povray recommends:
ii povray-includes 1:3.6.1-12 Persistance of vision raytracer (3
Versions of packages povray suggests:
pn kpovmodeler <none> (no description available)
ii povray-doc 1:3.6.1-12 Persistence of vision raytracer (3
ii povray-examples 1:3.6.1-12 Persistence of vision raytracer (3
-- Configuration Files:
/etc/povray/3.6/povray.conf changed [not included]
-- no debconf information
--
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