hi,

=?UTF-8?Q?J=c3=b6rg_=22Yadgar=22_Bleimann?= <yaz### [at] gmxde> wrote:
> On 13.08.20 21:03, jr wrote:
> > "jr" <cre### [at] gmailcom> wrote:
> >> ...
> > the increments where you make the vector for 'eval_pigment', pretty sure you'll
> > want '<(.5+b)*(1/xdim), (.5+a)*(1/ydim),0>'.
>
> As the data tile is square, xdim = ydim! Of course you're right, if I
> ever wanted to render a non-square data set, it's better to have the two
> variables assigned to the proper dimensions.

re square vs non-square -- if you use the method suggested by BE, ie using
'max_extent' to obtain '[xy]dim', you never need to know, nor care.

re code -- I think that you will see improved performance if you, again, follow
the advice given by BE regarding pre-calculating what you can.  so '[xy]dim' are
constant, for that bit of code, and not calculating both in the inner loop
removes two (relatively) expensive (division) operations; furthermore, file
system operations too are expensive, so consolidating the '#write's should make
a noticeable difference.  suggest bracket yr existing code with '#declare before
= now;' and '#declare after = now;' and run two or three times to get the number
of seconds, then replace yr code with the below, and compare.  I'd be v
interested to find out what savings that makes for the large kind of image
you're playing with.

   #declare i=0;
   #write (ES, "  texture_list")
   #write (ES, "  {\n")
   #write (ES, concat("    ",str(NumTextures, 1, 0),"\n"))
   #declare xincr = 1 / xdim;
   #declare yincr = 1 / ydim;
   #declare before = now;
   #for (a, 0, ydim-1)
     #for (b, 0, xdim-1)
       #declare C_Texture = eval_pigment(P_Texture,
<(.5+b)*xincr,(0.5+a)*yincr,0>);
       #write (ES, concat("    texture\n",
                          "    {\n",
                          "      pigment\n",
                          "      {\n",
                          "        color rgb <",
                          vstr(3, C_Texture, ",", 1, 7),
                          ">\n",
                          "      }\n",
                          "    }\n"))
     #end
   #end
   #write (ES, "  }\n")
   #declare after = now;


regards, jr.

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