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 Martin Nyolt - 2010-01-04
Last edited by Christoph Lipka - 2010-04-15
FS#74 - image_maps within pigment_maps are not rendered correctly
Hello,
when I use an image_map within a pigment_map (for example only a half of a box gets the image_map), the image_map is not rendered correctly.
For example when I have this box (scene and images are attached)
box {
0, 1
pigment {
gradient z
pigment_map {
[0.4 image_map { png "test.png" } ]
[0.4 color Cyan ]
}
}
}
So on the front you should see the image of test.png (in the attached scene it’s just red).
But on some pixels of the front you see the cyan color of the distant half of the cube.
Rendering the scene mutliple times produces the same result.
Rendering the scene at 200×150 is sufficiant.
povray +W200 +H150 scene.pov
I tested it with 3.6.1 and 3.7.0 beta 32 on Linux
scene.tar.bz2
(5.2 KiB)
Sorry, I tested it with beta 34 instead of beta 32
I realized now this bug happens with any pigment I use:
box { 0, 1 pigment { gradient z pigment_map { [0.4 color Red ] [0.4 color Cyan ] } } finish { ambient 1 } }Or am I just misusing the pigment_map?
Note that gradient is a repeating pattern, giving - in this case undesired - additional sharp transitions at multiples of 1.0, which in the examples happen to coincide with the faces of the box. Hence the observed issues are probably a member of the "coincident surfaces" family of problems.
In this particular case the issue can be circumvented by using a "planar" pattern instead, or using the gradient pattern with the "triangle_wave" keyword.
Closing this task, as it is not a bug but just an unexpected effect.