The Persistence of Vision Raytracer (POV-Ray).

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Attached to Project: POV-Ray
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


The problem seems to affect bozo, bumps, dents, granite, spotted,
and maybe wrinkles. The problem was reported earlier in


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
    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]

  z, 10
  texture {T_STRANDS1}
  //texture {T_STRANDS2}
Closed by  Chris Cason
Wednesday, 15 December 2010, 19:05 GMT
Reason for closing:  Fixed
Christoph Lipka commented on Saturday, 30 October 2010, 14:44 GMT

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.

Christoph Lipka commented on Saturday, 30 October 2010, 15:24 GMT

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.

Christoph Lipka commented on Monday, 01 November 2010, 17:56 GMT

fixed with change #5179

Grimbert Jérôme commented on Monday, 08 November 2010, 17:17 GMT

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).


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