POV-Ray

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.

Attached to Project: POV-Ray
Opened by Christoph Lipka - 2009-11-11
Last edited by Christoph Lipka - 2010-06-19

FS#67 - alpha channel in image map is ignored for shadows

In the following scene, the mesh object will always cast a fully-opaque shadow, even if the image has an alpha channel:

camera {
  location  <0.5, 1.0, -1.0>
  look_at   <0.5, 0.0,  0.5>
}

light_source { <0, 30, 0> color rgb 1 }

mesh {
    triangle { <0,0,0>, <1,0,0>, <1,0,1> uv_vectors <0,0>, <1,0>, <1,1> }
    triangle { <0,0,0>, <1,0,1>, <0,0,1> uv_vectors <0,0>, <1,1>, <0,1> }
    texture { pigment { uv_mapping image_map {png "FOOBAR.png"} } }
}

plane { y, -0.1 pigment { color rgb 1 } }

The following modification to the texture will give the expected results:

    texture { uv_mapping pigment { image_map {png "FOOBAR.png"} } }

The problem can be observed with both POV-Ray 3.7 (tested with beta.34), as well as 3.6 (tested with 3.6.2).

Closed by  Christoph Lipka
Saturday, 19 June 2010, 12:47 GMT
Reason for closing:  Fixed
Admin
Christoph Lipka commented on Wednesday, 11 November 2009, 19:05 GMT

First analysis shows that the parser erroneously identifies the problematic construct as an opaque texture, setting a flag on the object that causes the shadow handling code to completely bypass examination of the object's materials.

Admin
Christoph Lipka commented on Friday, 26 March 2010, 17:35 GMT

fixed in change #4933

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