POV-Ray : Newsgroups : povray.beta-test : Light_sources in light_groups don't cast shadows Server Time
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From: Thorsten Froehlich
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 24 Nov 2001 04:56:19
Message: <3bff6ec3$1@news.povray.org>
In article <3bff6344@news.povray.org> , "Bob H." <omn### [at] msncom> wrote:

> "JRG" <jrg### [at] hotmailcom> wrote in message
> news:3bff576a@news.povray.org...
>> Bob H wrote:
>> > Hmm, I've rendered your test scene and I get a shadow across the text
>> coming
>> > from the torus
>>
>> Really?! Well, I don't (both compiles). I get that shadow only if I
>> comment
>> out the light_group.
>>
>> POV-Ray v3.5 Windows ME Athlon.
>
> Wouldn't that be strange if it's due to the Athlon processor...?
> I didn't change a thing from your example script and the torus shadow
> certainly crossed the text from halfway up to the lowest part.  Just to
> clarify that.

I can reproduce this.  Below is a simpler version without all the
unnecessary declares and a font one can find on othere systems as well.

camera
{
  location  <0, 2, -4>
  look_at   <0, 0, 0>
}

light_group {
 light_source
 {
  <0, 5, -3>
  rgb 1
 }

 text {ttf "times.ttf" "TEXT" 1,0 pigment {rgb 1} translate <-1,1,-2>}
 torus {1.75,0.25 pigment {rgb 1}}
}


____________________________________________________
Thorsten Froehlich
e-mail: mac### [at] povrayorg

I am a member of the POV-Ray Team.
Visit POV-Ray on the web: http://mac.povray.org


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From: Bob H 
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 24 Nov 2001 08:03:48
Message: <3bff9ab4@news.povray.org>
"Thorsten Froehlich" <tho### [at] trfde> wrote in message
news:3bff6ec3$1@news.povray.org...
>
> I can reproduce this.  Below is a simpler version without all the
> unnecessary declares and a font one can find on other systems as well.

Okay, are you saying I should not be seeing a shadow of the text falling
onto the torus, or that it does?  I do see the shadow.
In case this is going to matter, my system is Intel P3 with WinXP.

Bob H.

> camera
> {
>   location  <0, 2, -4>
>   look_at   <0, 0, 0>
> }
>
> light_group {
>  light_source
>  {
>   <0, 5, -3>
>   rgb 1
>  }
>
>  text {ttf "times.ttf" "TEXT" 1,0 pigment {rgb 1} translate <-1,1,-2>}
>  torus {1.75,0.25 pigment {rgb 1}}
> }
>
>
> ____________________________________________________
> Thorsten Froehlich
> e-mail: mac### [at] povrayorg
>
> I am a member of the POV-Ray Team.
> Visit POV-Ray on the web: http://mac.povray.org


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From: JRG
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 24 Nov 2001 08:45:14
Message: <3bffa46a@news.povray.org>
I've posted the image showing the problem to beta-test.binaries.

--
Jonathan.


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From: JRG
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 24 Nov 2001 09:09:51
Message: <3bffaa2f@news.povray.org>
I got it. If you turn light buffers off it works fine. So it must be a bug.

--
Jonathan.


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From: Bob H 
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 24 Nov 2001 09:18:13
Message: <3bffac25@news.povray.org>
"JRG" <jrg### [at] hotmailcom> wrote in message
news:3bffaa2f@news.povray.org...
> I got it. If you turn light buffers off it works fine. So it must be a
bug.

Yes, must be.  Especially since I can use either -ul or +ul.  Light buffer
on or off is the same for me here.


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From: JRG
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 24 Nov 2001 09:25:20
Message: <3bffadd0@news.povray.org>
Not for me: with +ul the bug manifests itself, with -ul it doesn't. It's
really strange...
Maybe light buffers work unexpectedly in XP? I mean, there's a bug, but with
XP it doesn't show. Any other XP users here?

--
Jonathan.


"Bob H." <omn### [at] msncom> ha scritto nel messaggio
news:3bffac25@news.povray.org...
> "JRG" <jrg### [at] hotmailcom> wrote in message
> news:3bffaa2f@news.povray.org...
> > I got it. If you turn light buffers off it works fine. So it must be a
> bug.
>
> Yes, must be.  Especially since I can use either -ul or +ul.  Light buffer
> on or off is the same for me here.
>
>
>


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From: Thorsten Froehlich
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 24 Nov 2001 10:20:12
Message: <3bffbaac@news.povray.org>
In article <3bffadd0@news.povray.org> , "JRG" <jrg### [at] hotmailcom> wrote:

> Maybe light buffers work unexpectedly in XP? I mean, there's a bug, but with
> XP it doesn't show. Any other XP users here?

The core code does not depend on the operating system (besides, one thing is
for sure: I am not using WinDOS XP).  Don't jump to such conclusions.  There
are a million reasons why it cannot work, none of which has to do with the
operating system.  Only the source code can tell...

    Thorsten

____________________________________________________
Thorsten Froehlich
e-mail: mac### [at] povrayorg

I am a member of the POV-Ray Team.
Visit POV-Ray on the web: http://mac.povray.org


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From: Mike Williams
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 24 Nov 2001 12:33:41
Message: <hyp$TDARd5$7EwaR@econym.demon.co.uk>
Wasn't it Marc-Hendrik Bremer who wrote:

>I don't get shadows either. Can't be the Athlon.

I'm going to log this as a confirmed bug, even though I'm not entirely
sure of the conditions under which the shadows are present.

On my system there are no shadows in either of the examples posted.

Here's my, rather confusing, contribution to the fray - no text object,
just spheres and boxes for simplicity.



camera { location  <0, 2, -3>
         look_at   0
}
    
light_group {
  light_source { <-1, 3, 1> rgb 1}
  sphere {y,0.5 pigment {rgb 1}}
  box {<-1,0,-1><1,0.5,1> pigment {rgb 1}}
}

//  sphere {<4,-5,10>,0.5 pigment {rgb 1}}

background {rgb z}



On my machine, as written, the sphere casts a shadow on the box.
However, when I uncomment the second sphere the shadow disappears. The
existence of any extra object seems to switch off the shadow. Even if
the second sphere is moved inside the light group it kills the shadow.

3.5b7 (both versions), Celeron II 800, W98se, 128Mb

-- 
Mike Williams
Gentleman of Leisure


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From: Marc-Hendrik Bremer
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 24 Nov 2001 13:28:14
Message: <3bffe6be@news.povray.org>
Mike Williams schrieb ...

>On my machine, as written, the sphere casts a shadow on the box.
>However, when I uncomment the second sphere the shadow disappears. The
>existence of any extra object seems to switch off the shadow. Even if
>the second sphere is moved inside the light group it kills the shadow.
>

I can confirm this behavior with your script. It is cured by using -ul in
this case, too.

Marc-Hendrik

PII450, Win98, 128 MB, Pov 3.5 beta 7


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From: JRG
Subject: Re: Light_sources in light_groups don't cast shadows
Date: 25 Nov 2001 06:30:22
Message: <3c00d64e@news.povray.org>
Of course, my fault. Sorry.

--
Jonathan.
"Thorsten Froehlich" <tho### [at] trfde> ha scritto nel messaggio
news:3bffbaac@news.povray.org...
> In article <3bffadd0@news.povray.org> , "JRG" <jrg### [at] hotmailcom> wrote:
>
> > Maybe light buffers work unexpectedly in XP? I mean, there's a bug, but
with
> > XP it doesn't show. Any other XP users here?
>
> The core code does not depend on the operating system (besides, one thing
is
> for sure: I am not using WinDOS XP).  Don't jump to such conclusions.
There
> are a million reasons why it cannot work, none of which has to do with the
> operating system.  Only the source code can tell...
>
>     Thorsten
>
> ____________________________________________________
> Thorsten Froehlich
> e-mail: mac### [at] povrayorg
>
> I am a member of the POV-Ray Team.
> Visit POV-Ray on the web: http://mac.povray.org


Post a reply to this message

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