POV-Ray : Newsgroups : povray.binaries.images : Amazonas : Re: Amazonas Server Time
24 Mar 2023 15:30:06 EDT (-0400)
  Re: Amazonas  
From: Jaime Vives Piqueres
Date: 18 May 2010 08:59:55
Message: <4bf28f4b@news.povray.org>

> Awesome!


> How do you place trees with a pigment function? I would like to do the
> same with the grass in my alley scene, so the grass won't grow on the
> asphalt...

   Indeed you could use this technique for that... it's very easy, specially
if you are already using a heighfield for the ground. Make a copy of the
grayscale map, and paint black the zones where you don't want grass, and
white for the rest. Then declare a pigment function of it:

#declare f_grass_distribution=
     image_map{png "your_image.png"}
     rotate 90*x
     translate <-.5,0,-.5>
     scale as_your_heightfield

   Now, build the classic while loop where you shot the heighfield with
trace(), but for each placement found, test first if the grass distribution
allows a grass patch there:

   #if (f_grass_distribution(Inter.x,0,Inter.z).gray>0)
      translate Inter

   Hope this helps...

Jaime Vives Piqueres


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