POV-Ray : Newsgroups : povray.binaries.images : (alpha channel not work )Another example Server Time
5 Jul 2024 07:12:39 EDT (-0400)
  (alpha channel not work )Another example (Message 1 to 8 of 8)  
From: liujg
Subject: (alpha channel not work )Another example
Date: 6 Aug 2014 03:05:04
Message: <web.53e1d3332a4d6c721ccfd0a0@news.povray.org>
background {
  color rgb < 0.60, 0.70, 0.95 >
}
camera {
  location <0, 15, -60>
 direction <0, 2,  1>
  right x*1.33
 look_at <0,15,0>
}
light_source {
  <0,28,0> // position of a coner of the light plane
  rgb<1.0,1.0,1.0>
  area_light <3, 0, 0>, <0, 3, 0>, 2, 2 // light plane's edges; m by n bulbs
 adaptive 1 // if on, some rays will not be traced
 jitter // randomization of bulb's positions, emulating fuzzy shadow edges
}

  object {
      mesh2{
         vertex_vectors{
                      5
                        <-500, 0, 30>, < 500, 0, 30>,<500,  500, 30>, < -500,
500, 30>  , < 0, 250,  30>

                       }
             uv_vectors{
                       5
                         <-25.0, -25.0>,< 25.0, -25.0> ,  < 25.0,  25.0>,
<-25.0,  25.0>,  <0.0, 0.0>
                       }
           face_indices{
                       4,
                        <0,1,4>, <1,2,4>,<2,3,4>, <3,0,4>

                       }
             uv_indices{
                     4,
                        <0,1,4>, <1,2,4>,<2,3,4>, <3,0,4>

                        }

            }
     texture{
         pigment{
       uv_mapping
        image_map { png "DHKX0221.png"  map_type 0   interpolate 2 }
                }
         finish {
      specular 0.3
      roughness 0.01
                }
            }
}


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Attachments:
Download 'dhkx0221.png' (1250 KB)

Preview of image 'dhkx0221.png'
dhkx0221.png


 

From: liujg
Subject: Re: (alpha channel not work )Another example
Date: 6 Aug 2014 03:10:04
Message: <web.53e1d4788bdc3f3e1ccfd0a0@news.povray.org>
"liujg" <seu### [at] qqcom> wrote:
> background {
>   color rgb < 0.60, 0.70, 0.95 >
> }
> camera {
>   location <0, 15, -60>
>  direction <0, 2,  1>
>   right x*1.33
>  look_at <0,15,0>
> }
> light_source {
>   <0,28,0> // position of a coner of the light plane
>   rgb<1.0,1.0,1.0>
>   area_light <3, 0, 0>, <0, 3, 0>, 2, 2 // light plane's edges; m by n bulbs
>  adaptive 1 // if on, some rays will not be traced
>  jitter // randomization of bulb's positions, emulating fuzzy shadow edges
> }
>
>   object {
>       mesh2{
>          vertex_vectors{
>                       5
>                         <-500, 0, 30>, < 500, 0, 30>,<500,  500, 30>, < -500,
> 500, 30>  , < 0, 250,  30>
>
>                        }
>              uv_vectors{
>                        5
>                          <-25.0, -25.0>,< 25.0, -25.0> ,  < 25.0,  25.0>,
> <-25.0,  25.0>,  <0.0, 0.0>
>                        }
>            face_indices{
>                        4,
>                         <0,1,4>, <1,2,4>,<2,3,4>, <3,0,4>
>
>                        }
>              uv_indices{
>                      4,
>                         <0,1,4>, <1,2,4>,<2,3,4>, <3,0,4>
>
>                         }
>
>             }
>      texture{
>          pigment{
>        uv_mapping
>         image_map { png "DHKX0221.png"  map_type 0   interpolate 2 }
>                 }
>          finish {
>       specular 0.3
>       roughness 0.01
>                 }
>             }
> }

the render result.


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Attachments:
Download 'qq??20140806144335.jpg' (101 KB)

Preview of image 'qq??20140806144335.jpg'
qq??20140806144335.jpg


 

From: liujg
Subject: Re: (alpha channel not work )Another example
Date: 6 Aug 2014 03:20:04
Message: <web.53e1d6b28bdc3f3e1ccfd0a0@news.povray.org>
"liujg" <seu### [at] qqcom> wrote:
> "liujg" <seu### [at] qqcom> wrote:
> > background {
> >   color rgb < 0.60, 0.70, 0.95 >
> > }
> > camera {
> >   location <0, 15, -60>
> >  direction <0, 2,  1>
> >   right x*1.33
> >  look_at <0,15,0>
> > }
> > light_source {
> >   <0,28,0> // position of a coner of the light plane
> >   rgb<1.0,1.0,1.0>
> >   area_light <3, 0, 0>, <0, 3, 0>, 2, 2 // light plane's edges; m by n bulbs
> >  adaptive 1 // if on, some rays will not be traced
> >  jitter // randomization of bulb's positions, emulating fuzzy shadow edges
> > }
> >
> >   object {
> >       mesh2{
> >          vertex_vectors{
> >                       5
> >                         <-500, 0, 30>, < 500, 0, 30>,<500,  500, 30>, < -500,
> > 500, 30>  , < 0, 250,  30>
> >
> >                        }
> >              uv_vectors{
> >                        5
> >                          <-25.0, -25.0>,< 25.0, -25.0> ,  < 25.0,  25.0>,
> > <-25.0,  25.0>,  <0.0, 0.0>
> >                        }
> >            face_indices{
> >                        4,
> >                         <0,1,4>, <1,2,4>,<2,3,4>, <3,0,4>
> >
> >                        }
> >              uv_indices{
> >                      4,
> >                         <0,1,4>, <1,2,4>,<2,3,4>, <3,0,4>
> >
> >                         }
> >
> >             }
> >      texture{
> >          pigment{
> >        uv_mapping
> >         image_map { png "DHKX0221.png"  map_type 0   interpolate 2 }
> >                 }
> >          finish {
> >       specular 0.3
> >       roughness 0.01
> >                 }
> >             }
> > }
>
> the render result.


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Attachments:
Download '123.png' (262 KB)

Preview of image '123.png'
123.png


 

From: Le Forgeron
Subject: Re: (alpha channel not work )Another example
Date: 6 Aug 2014 04:09:34
Message: <53e1e2be@news.povray.org>
Check your png.

The alpha channel is present, but in the attached image of the previous
message, it is 100% opaque everywhere.

So far, povray is working as expected. You need to have less than 100%
opaque in part of your png to see it as transparent (even partially) in
the rendered image.


-- 
Just because nobody complains does not mean all parachutes are perfect.


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From: Alain
Subject: Re: (alpha channel not work )Another example
Date: 6 Aug 2014 18:48:36
Message: <53e2b0c4$1@news.povray.org>

> background {
>    color rgb < 0.60, 0.70, 0.95 >
> }
> camera {
>    location <0, 15, -60>
>   direction <0, 2,  1>
>    right x*1.33
>   look_at <0,15,0>
> }
> light_source {
>    <0,28,0> // position of a coner of the light plane
>    rgb<1.0,1.0,1.0>
>    area_light <3, 0, 0>, <0, 3, 0>, 2, 2 // light plane's edges; m by n bulbs
>   adaptive 1 // if on, some rays will not be traced
>   jitter // randomization of bulb's positions, emulating fuzzy shadow edges
> }
>

The adaptive feature value is NOT a boolean value but an initial or 
minimal subdivision value.
It's turned ON by the sole presence of the keyword "adaptive" followed 
by some value, even zero.

adaptive 0 will shoot at least 4 rays in a 2 by 2 array, the size of 
your array.
adaptive 1 will attempt to shoot at least 9 rays in a 3 by 3 array, but 
your array, at 2 by 2, is not large enough.
adaptive 2 will attempt to shoot at least 25 rays in a 5 by 5 array
If a dimention for the sublights is to small in any direction to allow 
for the desired minimal subdivision, it won't attempt to subdivide further.
Using an area_light 3*x, 3*y, 2, 2 with adaptive is totaly pointless.

Using this area_light setting is prety fast and gives very smooth results:
area_light 3*x, 3*y, 33 33 adaptive 0
You can go overboard:
area_light 3*x, 3*y, 1025 1025 adaptive 0
whitch is almost as fast and so smooth that jitter not usefull.



Alain


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From: liujg
Subject: Re: (alpha channel not work )Another example
Date: 6 Aug 2014 21:40:01
Message: <web.53e2d81b8bdc3f3e99daad1c0@news.povray.org>
Alain <kua### [at] videotronca> wrote:

> > background {
> >    color rgb < 0.60, 0.70, 0.95 >
> > }
> > camera {
> >    location <0, 15, -60>
> >   direction <0, 2,  1>
> >    right x*1.33
> >   look_at <0,15,0>
> > }
> > light_source {
> >    <0,28,0> // position of a coner of the light plane
> >    rgb<1.0,1.0,1.0>
> >    area_light <3, 0, 0>, <0, 3, 0>, 2, 2 // light plane's edges; m by n bulbs
> >   adaptive 1 // if on, some rays will not be traced
> >   jitter // randomization of bulb's positions, emulating fuzzy shadow edges
> > }
> >
>
> The adaptive feature value is NOT a boolean value but an initial or
> minimal subdivision value.
> It's turned ON by the sole presence of the keyword "adaptive" followed
> by some value, even zero.
>
> adaptive 0 will shoot at least 4 rays in a 2 by 2 array, the size of
> your array.
> adaptive 1 will attempt to shoot at least 9 rays in a 3 by 3 array, but
> your array, at 2 by 2, is not large enough.
> adaptive 2 will attempt to shoot at least 25 rays in a 5 by 5 array
> If a dimention for the sublights is to small in any direction to allow
> for the desired minimal subdivision, it won't attempt to subdivide further.
> Using an area_light 3*x, 3*y, 2, 2 with adaptive is totaly pointless.
>
> Using this area_light setting is prety fast and gives very smooth results:
> area_light 3*x, 3*y, 33 33 adaptive 0
> You can go overboard:
> area_light 3*x, 3*y, 1025 1025 adaptive 0
> whitch is almost as fast and so smooth that jitter not usefull.
>
>
>
> Alain
Thank you ,My question is that in the render result picture the black area
should be transparent,because my bitmap have alpha channel .


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From: Patrick Elliott
Subject: Re: (alpha channel not work )Another example
Date: 7 Aug 2014 00:23:33
Message: <53e2ff45$1@news.povray.org>
On 8/6/2014 6:36 PM, liujg wrote:
> Alain <kua### [at] videotronca> wrote:

>>> background {
>>>     color rgb < 0.60, 0.70, 0.95 >
>>> }
>>> camera {
>>>     location <0, 15, -60>
>>>    direction <0, 2,  1>
>>>     right x*1.33
>>>    look_at <0,15,0>
>>> }
>>> light_source {
>>>     <0,28,0> // position of a coner of the light plane
>>>     rgb<1.0,1.0,1.0>
>>>     area_light <3, 0, 0>, <0, 3, 0>, 2, 2 // light plane's edges; m by n bulbs
>>>    adaptive 1 // if on, some rays will not be traced
>>>    jitter // randomization of bulb's positions, emulating fuzzy shadow edges
>>> }
>>>
>>
>> The adaptive feature value is NOT a boolean value but an initial or
>> minimal subdivision value.
>> It's turned ON by the sole presence of the keyword "adaptive" followed
>> by some value, even zero.
>>
>> adaptive 0 will shoot at least 4 rays in a 2 by 2 array, the size of
>> your array.
>> adaptive 1 will attempt to shoot at least 9 rays in a 3 by 3 array, but
>> your array, at 2 by 2, is not large enough.
>> adaptive 2 will attempt to shoot at least 25 rays in a 5 by 5 array
>> If a dimention for the sublights is to small in any direction to allow
>> for the desired minimal subdivision, it won't attempt to subdivide further.
>> Using an area_light 3*x, 3*y, 2, 2 with adaptive is totaly pointless.
>>
>> Using this area_light setting is prety fast and gives very smooth results:
>> area_light 3*x, 3*y, 33 33 adaptive 0
>> You can go overboard:
>> area_light 3*x, 3*y, 1025 1025 adaptive 0
>> whitch is almost as fast and so smooth that jitter not usefull.
>>
>>
>>
>> Alain
> Thank you ,My question is that in the render result picture the black area
> should be transparent,because my bitmap have alpha channel .
>
>
You may be misunderstanding the alpha channel, and how it works. We 
would need to see the actually png, to be sure, but.. its not like a 
gif, there isn't just "one color" that functions as an "alpha channel". 
In png, the colors are stored as red, green, blue, alpha. The last one 
can be anything from 100% visible, to 100% see through, and anything in 
between. The only reason why alpha, as far as I know, can possible not 
work in POVRay is if your imagine has the color <0,0,0,0> for the parts 
you want to see through - which would mean Black, 100% visible. I.e., 
the png *may* contain alpha information, but the "color" you are trying 
to see through "does not contain any".

-- 
Commander Vimes: "You take a bunch of people who don't seem any 
different from you and me, but when you add them all together you get 
this sort of huge raving maniac with national borders and an anthem."


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From: Alain
Subject: Re: (alpha channel not work )Another example
Date: 8 Aug 2014 19:27:13
Message: <53e55cd1@news.povray.org>

> Alain <kua### [at] videotronca> wrote:

>>> background {
>>>     color rgb < 0.60, 0.70, 0.95 >
>>> }
>>> camera {
>>>     location <0, 15, -60>
>>>    direction <0, 2,  1>
>>>     right x*1.33
>>>    look_at <0,15,0>
>>> }
>>> light_source {
>>>     <0,28,0> // position of a coner of the light plane
>>>     rgb<1.0,1.0,1.0>
>>>     area_light <3, 0, 0>, <0, 3, 0>, 2, 2 // light plane's edges; m by n bulbs
>>>    adaptive 1 // if on, some rays will not be traced
>>>    jitter // randomization of bulb's positions, emulating fuzzy shadow edges
>>> }
>>>
>>
>> The adaptive feature value is NOT a boolean value but an initial or
>> minimal subdivision value.
>> It's turned ON by the sole presence of the keyword "adaptive" followed
>> by some value, even zero.
>>
>> adaptive 0 will shoot at least 4 rays in a 2 by 2 array, the size of
>> your array.
>> adaptive 1 will attempt to shoot at least 9 rays in a 3 by 3 array, but
>> your array, at 2 by 2, is not large enough.
>> adaptive 2 will attempt to shoot at least 25 rays in a 5 by 5 array
>> If a dimention for the sublights is to small in any direction to allow
>> for the desired minimal subdivision, it won't attempt to subdivide further.
>> Using an area_light 3*x, 3*y, 2, 2 with adaptive is totaly pointless.
>>
>> Using this area_light setting is prety fast and gives very smooth results:
>> area_light 3*x, 3*y, 33 33 adaptive 0
>> You can go overboard:
>> area_light 3*x, 3*y, 1025 1025 adaptive 0
>> whitch is almost as fast and so smooth that jitter not usefull.
>>
>>
>>
>> Alain
> Thank you ,My question is that in the render result picture the black area
> should be transparent,because my bitmap have alpha channel .
>
>

Your image DOES have an alpha channel, but that channel say "this pixel 
have zero transparency" everywhere. If the alpha channel was correct, 
then Thunderbird would show the background colour of the page instead of 
black. Also, in the web version, just any browser should also show the 
black areas as transparent, meaning that any background will show 
through. This _IS NOT THE CASE_ with your image !

The fact that a given pixel is black *never ever* make it transparent. 
In fact, it can be absolutely any colour of the 16.4 millions available.




Alain


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