The Persistence of Vision Raytracer (POV-Ray).

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Attached to Project: POV-Ray
Opened by Olaf Reinhold - 2009-09-03
Last edited by Christoph Lipka - 2010-03-26

FS#55 - Output_Alpha=on doesn't work as documented

I have installed POV-Ray 3.7 beta 34 on Windows 7
The setting ‘Output_Alpha=on’ doesn’t work as documented. With this setting the Background appear black and the scene is transparent.

Check with this Code:

camera {
   location  <3, 3, -3>
   direction <0, 0, 2.9>
   look_at   <0, 0, 0>
   right 1.0*x
light_source { < 3, 3, -3> color red 1 green 1 blue 1 }
   <0,0,0> 0.8
   pigment {color rgb<1,1,0>}
      ambient 0.2
      diffuse 0.8

and with this ini file:

+W121 +H121
Closed by  Christoph Lipka
Friday, 26 March 2010, 16:53 GMT
Reason for closing:  Fixed
Additional comments about closing:  

No feedback from beta testers for months, so probably "no news is good news"

Christoph Lipka commented on Wednesday, 09 September 2009, 10:23 GMT

Behavior is indeed different from 3.6.

As POV-Ray uses a transmit value with fully opaque defined as 0.0 and fully transparent defined as 1.0, but TGA format uses an alpha value with values defined the other way round, this needs to be corrected; apparently, in refactoring of the image data container to store alpha instead of transparency, this correction was duplicated, with the effect of cancelling it out.

Christoph Lipka commented on Wednesday, 09 September 2009, 10:36 GMT

fixed with change #4886


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