POV-Ray : Newsgroups : povray.unofficial.patches : Initial povr branch keywords id_type() and id_types_match() : Re: Initial povr branch keywords id_type() and id_types_match() Server Time
21 Apr 2024 08:17:26 EDT (-0400)
  Re: Initial povr branch keywords id_type() and id_types_match()  
From: William F Pokorny
Date: 27 May 2021 05:50:17
Message: <60af6b59$1@news.povray.org>
On 5/27/21 2:08 AM, jr wrote:
> hi,
> 
> William F Pokorny <ano### [at] anonymousorg> wrote:
>> On 5/25/21 8:40 AM, jr wrote:
>>> could it be implemented as-easily in POV-Ray
>>> too?
>>
>> You, and that concept of easy... ;-)
> 
> my ignorance wrt POV-Ray source stands me in good stead..  :-)

:-) Me alongside. Nobody understands the whole of the code base.

> 
> 
>> As implemented it's a stand alone bit of code.
> 
> that is good.  (afaict)  so it could be issued as a patch to the 3.8.0-alpha?
> 

Could be. Yes.

> 
>> Aside: I did manage to use some of the object flags to break out
>> light_sources, csg (merge,union,difference,intersection), light unions
>> and light groups from the object id category. The id sub-catagories Left
>> in as probably more useful than not, but there is the nagging thought it
>> might somewhere be the wrong thing to do.
> 
> forgot to thank you for the vector id background info.  read in conjunction with
> the above, I'm thinking a two function approach perhaps, 'id_type' much as is,
> supported by a similar function which returns an 'array mixed' with the various
> "properties"/categories broken out?
> 

What I've not done for arrays vs mixed arrays as yet is look for a 
method 'like' that employed to break out a few of the object types like 
light sources(1). The object flags popped into my head on Tor Olav's 
question.

Even without getting different type ids for arrays vs mixed arrays today 
from id_type, you can walk a mixed array asking about the types for each 
element and in that way via SDL looping (or your foreach work) build up 
what types in total are seen for any given the mixed array.

(1) - Strictly, the information isn't needed for code safety sake. We 
can today (v3.8) employ the back door type checking I mentioned 
'somewhere' to be sure types coming in via mixed arrays are consistent - 
when then need to be. I used the technique while adopting Tor Olav's 
array statics macro suggestions. Let me see, as two examples, I used the 
trick with his Mean and Minimum macros which now look like:

#macro Mean(Values)

     #local N = dimension_size(Values, 1);
     #local Sum = array[1] // Fixed array types cannot change.
     #local Sum[0] = Values[0];
     #for (I, 1, N - 1)
         #local Sum[0] = Sum[0] + Values[I];
     #end // for

     (Sum[0]/N)

#end // macro Mean

#macro Minimum(Values)

     #local N = dimension_size(Values, 1);
     #local Min = array[2] {1,1} // Fixed array types cannot change.
     #local Min[0] = Values[0];  // Better err msg - min() floats only.
     #for (I, 1, N - 1)
         #local Min[1] = Values[I]; // Better err msg.
         #local Min[0] = min(Min[0], Min[1]);
     #end // for

     Min[0]

#end // macro Minimu

Bill P.


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