The Persistence of Vision Raytracer (POV-Ray).
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FS#168 - noise_generator default broken
Opened by Christian Froeschlin (froesccn) - Tuesday, 19 October 2010, 15:28 GMT
Last edited by Chris Cason (chrisc) - Wednesday, 15 December 2010, 19:05 GMT
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Details[Original Title: “texture_map interpolation does not work correctly for some patterns”]
The below test scene should yield identical textures http://news.povray.org/povray.general/thread/%3C4cbd804b%241%40news.povray.org%3E/
The problem seems to affect bozo, bumps, dents, granite, spotted, 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}
}
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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).