POV-Ray : Newsgroups : povray.advanced-users : Speeding up media : Re: Speeding up media Server Time
22 Jan 2022 19:55:41 EST (-0500)
  Re: Speeding up media  
From: Ash Holsenback
Date: 14 Feb 2021 11:02:43
Message: <602949a3$1@news.povray.org>
On 2/13/21 7:36 PM, William F Pokorny wrote:
> On 2/13/21 8:18 AM, Ash Holsenback wrote:
>> On 2/13/21 2:35 AM, Thomas de Groot wrote:
> ...
>>
>> spotted another difference with default for aa_level... 2nd paragraph 
>> after 1st note has it at 4
>>
>> while: http://wiki.povray.org/content/Reference:Media
>>
>> has it at 3... inquiring minds wanna know
>>
> 
> It looks like it is 3.
> 
> media.cpp has:
> 
> Media::Media()
> {
>      Type = ISOTROPIC_SCATTERING;
> 
>      Intervals      = 10;
>      Min_Samples    = 1;
>      Max_Samples    = 1;
>      Eccentricity   = 0.0;
> 
>      Absorption.Clear();
>      Emission.Clear();
>      Extinction.Clear();
>      Scattering.Clear();
> 
>      is_constant = false;
> 
>      use_absorption = false;
>      use_emission   = false;
>      use_extinction = false;
>      use_scattering = false;
> 
>      ignore_photons = false;
> 
>      sc_ext     = 1.0;
>      Ratio      = 0.9;
>      Confidence = 0.9;
>      Variance   = 1.0 / 128.0;
> 
>      Sample_Threshold = nullptr;
> 
>      Sample_Method = 1;
>      AA_Threshold = 0.1;
>      AA_Level = 3;
>      Jitter = 0.0;
> }
> 
> Before anyone jumps on the Intervals, Min_Samples, Max_Samples and 
> Sample_Method defaults above, in parser_materials.cpp we have:
> 
>      if (AllowToken(MEDIA_ID_TOKEN))
>          IMediaObj = CurrentTokenData<Media>();
>      else
>      {
>          /* as of v3.5, the default media method is now 3 */
>          if (sceneData->EffectiveLanguageVersion() >= 350)
>          {
>              IMedia->Intervals = 1;
>              IMedia->Min_Samples = 10;
>              IMedia->Max_Samples = 10;
>              IMedia->Sample_Method = 3;
>          }
>      }
> 
> ---
> Won't that parser override sometimes mess up the defaults for method 1 
> and 2 you ask. Yes, I think it well might... I'm not going to do the 
> work to prove it now, but likely media 1 & 2 users will 'always' have to 
> set the intervals to 10, min and max to 1 if they want documented 
> defaults for those two methods.
> 
> Bill P.
> 
> 
another question: are variance, confidence and ratio valid in method 
3... given current narrative i'd say yes to the first two and no on the last

made some progress... here's what i have so far
http://wiki.povray.org/content/Reference:Sampling_Parameters_%26_Methods


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