POV-Ray : Newsgroups : povray.binaries.images : Spherical displacement map : Re: Spherical displacement map Server Time: 28 Sep 2020 14:49:33 GMT
  Re: Spherical displacement map  
From: Bald Eagle
Date: 21 Jul 2020 01:15:01
William F Pokorny <ano### [at] anonymousorg> wrote:

> In the FWIW catagory, it looks like a function POVFPU_Exception() was
> mostly commented out in v3.7 and remains unchanged in v3.8. There are
> some TODOs in the code for it. It's still called from many places in the
> vm code, but...
>
> Bill P.

Well, it might have helped a bit to have an error message similar to "domain
error in atan2" or "divide by zero error", etc. before it shit the bed.

I'm still struggling with getting a good transition from the isosurface volume
coordinates to uv coordinates via the intermediate latitude/longitude values.

While what posted looks good superficially, I have a hole at the South pole, and
likely a similar issue at the North pole.

In my head, I should be able to take every <x,y,z> and convert it to a lat/long
pair (artificially constraining them to the proper domain) [maybe this is where
the error is], and then there should  be a 1:1 [Abelian?] mapping between that
and the 0-1 domain of the x and y of the image map (the u,v).

Here's a plot of my uv's calculated from a cube from -3, +3


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