POV-Ray : Newsgroups : povray.general : I was wrong, image_pattern looks useful. Attn: Bald Eagle. : I was wrong, image_pattern looks useful. Attn: Bald Eagle. Server Time
13 Jun 2024 19:30:38 EDT (-0400)
  I was wrong, image_pattern looks useful. Attn: Bald Eagle.  
From: William F Pokorny
Date: 12 Mar 2023 12:29:11
Message: <640dfdd7$1@news.povray.org>
Hi Bill,

In some height_field thread I mentioned image_pattern was a 'different 
beast'.

This morning I looked at it again - and you're right - it fits with the 
height_field discussion in that it looks like an image_map alternative 
which converts a color pixels to grey on the fly. I'll have to play with 
the option.

Aside: I found only two uses in the sample stuff shipped with POV-Ray, 
One each in the portfolio allnormals.pov and allpatterns.pov code. The 
first has:

#declare Image_pattern = normal {
	pigment_pattern{image_pattern { png "mtmandj.png" }}
2}

which has me curious as to why both pigment_pattern and image_pattern 
are getting used as I think that will run the color to grey conversion 
twice. Maybe the image_pattern code creates a smaller internal image 
format? Hmm, but then what three channels does pigment_pattern use...

The second allpatterns use is:

#declare Image_pattern = pigment {image_pattern { png "mtmandj.png" }}

which looks useful.

Anyhow. I wonder if I was remembering some functionality other than 
image_pattern from 20 years back. There is too material_map, maybe I was 
wrongly thinking of that when I first blabbered about image_pattern. :-)

Bill P.


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