POV-Ray : Newsgroups : povray.bugreports : transparency bug... (scene included) Server Time
31 Oct 2024 23:31:57 EDT (-0400)
  transparency bug... (scene included) (Message 1 to 4 of 4)  
From: Stephane Hockenhull
Subject: transparency bug... (scene included)
Date: 29 Sep 1998 15:49:25
Message: <36112BC1.C320DD8F@videotron.ca>
the scene is a started turtle bowl (you know, the transparent plastic
thing with a tree in the middle  :)

and at some camera<->bowl_surface angle the ray are pitch black. (sound
like a prevented div-by-zero kind of bug)

I have an AMD K6-200MMX, 64Meg ram, win95, and this bug append every
time, on both 3.01 and 3.1

here's the scene:
--------------- cut here ------------------------
// "transparent" object that create a ?bug? every time
// I've tried it with povray 3.01 and 3.1

// see the last lines of the file


// ==== Standard POV-Ray Includes ====
#include "colors.inc"	// Standard Color definitions
#include "textures.inc"	// Standard Texture definitions

// ==== Additional Includes ====
#include "CHARS.INC"   // FIXME-add comments describing each of these
#include "CONSTS.INC"
#include "METALS.INC"
#include "SHAPES.INC"
#include "SHAPES2.INC"
#include "SHAPESQ.INC"
#include "SKIES.INC"
#include "STONES.INC"
#include "STONES2.INC"
#include "WOODMAPS.INC"
#include "WOODS.INC"


camera
{
  location  <-0.3 , 0.0 ,-5.0>
  look_at   <0.001 , 0.0 , 0.0> // tried to move the camera a bit to see
if wasn't a "div by zero" bug
                                // didnt change much
  rotate <20, 0, 0>
}


// create a regular point light source
light_source
{
  0*x // light's position (translated below)
  color red 0.75  green 0.75  blue 0.75  // light's color
  translate <0, 0, -5>
}

// create a regular point light source
light_source
{
  0*x // light's position (translated below)
  color red 1.0  green 1.0  blue 1.0  // light's color
  translate <-1, 2, -2>
}

// create a regular point light source
light_source
{
  0*x // light's position (translated below)
  color red 0.75  green 0.75  blue 0.75  // light's color
  translate <2, 10, 5>
}


plane
{
  y, 
  -0.1 
  texture {
          checker 
                  texture {
                          T_Wood10
                          rotate<32, 59, 12>
                          scale <2,2,2>
                  }
                  texture {
                          T_Wood11
                          rotate<60, 10, 34>
                          scale <2,2,2>
                  }                  
  }  
}

object {
 union {
   difference {
    cylinder // outer cyl
    {
      0*y,  0.5*y,  2
    }
    cylinder // inner substact (up)
    {
      0.2*y,  0.6*y,  1.9
    }
    cylinder //  inner substract (bottom)
    {
      0.1*y,  0.6*y,  1.8
    }
    torus {  // inner substract (bottom plastic curve)
       1.8, 0.1
       translate <0, 0.2, 0>
    }
   }

   torus { // bottom plastic curve
       1.9, 0.1
       translate <0, 0, 0>
   }

   torus { // top plastic curve
       1.95, 0.05
       translate <0, 0.5, 0>
   }
 }
 texture {
         pigment {
                 // use one or the other ... ?bug? with both
                 
                 color rgbft <0.9, 0.9, 1, 0.9, 0>
                 
                 //color rgbft <0.9, 0.9, 1, 0, 1>
         }
 }
 finish{
        phong 0.7
 }
}

--------------------- cut here ----------------------------------
Stephane Hockenhull
Rv[PotamSoft]
mailto:pot### [at] videotronca
http://pages.infinit.net/potam/


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From: Johannes Hubert
Subject: Re: transparency bug... (scene included)
Date: 29 Sep 1998 16:26:04
Message: <3611344c.0@news.povray.org>
Ouch! Not a bug!

Look in the docs for "max_trace_level"...

Johannes.


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From: Stephane Hockenhull
Subject: Re: transparency bug... (scene included)
Date: 30 Sep 1998 01:14:59
Message: <3611B04F.8B1B33ED@videotron.ca>
Johannes Hubert wrote:
> 
> Ouch! Not a bug!
> 
> Look in the docs for "max_trace_level"...
> 
> Johannes.

k, next time i'll post in general first to make sure it's a bug.

little suggestion: you might put a (one time, not for every rays :)
warning in povray, so that when max_trace_level is reached, it says:
"oups, max_trace_level reached, try raising it!" 

It should be simple to implement, and prevent raytracing-newbies like me
to complain about bug that are in fact protections from infinite and
almost-infinite loops :P

-- 
Stephane Hockenhull
Rv[PotamSoft]
mailto:pot### [at] videotronca
http://pages.infinit.net/potam/


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From: Thorsten Froehlich
Subject: Re: transparency bug... (scene included)
Date: 30 Sep 1998 01:36:36
Message: <3611b554.0@news.povray.org>
In article <3611B04F.8B1B33ED@videotron.ca> , Stephane Hockenhull <pot### [at] videotronca>
 wrote:

>It should be simple to implement, and prevent raytracing-newbies like me
>to complain about bug that are in fact protections from infinite and
>almost-infinite loops :P

Not loops, recursions... :-)   And if infinite, they will use all your stack space
until is reaches the heap and you would get a nice crash.


Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany


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