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 Christian Froeschlin - 2010-10-19
Last edited by Chris Cason - 2010-12-15
FS#168 - noise_generator default broken
[Original Title: “texture_map interpolation does not work correctly for some patterns”]
The below test scene should yield identical textures
T_STRAND1 and T_STRAND2 but this is not the case. Reported
and verified in
http://news.povray.org/povray.general/thread/%3C4cbd804b%241%40news.povray.org%3E/
The problem seems to affect bozo, bumps, dents, granite, spotted,
and maybe wrinkles. The problem was reported earlier in
http://news.povray.org/povray.beta-test/thread/%3C48112367%241%40news.povray.org%3E
with a comment that 3.6 gives the expected results
#declare C_STRAND = color rgb 1;
#declare C_CLEAR = color rgb 0;
#declare T_STRAND = texture
{
pigment {color C_STRAND}
}
#declare T_CLEAR = texture
{
pigment {color C_CLEAR}
}
#declare T_STRANDS1 = texture
{
pigment
{
granite scale 2 color_map
{
[0.0 color C_STRAND]
[0.5 color C_CLEAR]
[1.0 color C_CLEAR]
}
}
}
#declare T_STRANDS2 = texture
{
granite scale 2 texture_map
{
[0.0 T_STRAND]
[0.5 T_CLEAR]
[1.0 T_CLEAR]
}
}
plane
{
z, 10
texture {T_STRANDS1}
//texture {T_STRANDS2}
}
The root cause seems to be a failure of POV-Ray to properly initialize noise_generator to its official default of 2 when using patterns directly inside a texture{} statement, leaving the value set to 0. This results in the code behaving as if noise_generator was set to 1.
Further analysis reveals that the global noise_generator setting does not have any effect at all in POV-Ray 3.7:
- texture_map patterns invariably default to noise_generator 0 (effectively the same as 1).
- pigment_map patterns invariably default to noise_generator 2.
POV-Ray 3.6 has none of these issues.
fixed with change #5179
Confirmation that current perforce version (up to #5184) does make the issue goes away (so, #5179 is successful, as later # are not related).
For the record, it even seems that agate was also affected (it was very very subtle).