In article <3c77f65e@news.povray.org>,
 "Rune" <run### [at] mobilixnetdk> wrote:

> What option?

The mapping warps/image map mappings.


> The mapping warps were never designed to apply to an object with any
> alignment in space. Thus the mappings can't be used for the purpose of
> mapping the square from <0,0> to <1,1> onto any sphere or cylinder without
> considerable work from the user. That's why I want it to be an option
> directly implemented in the macros.

As I said, a deficiency of the mappings. And it isn't that much 
work...at least, no more work than mapping an image texture onto a 
cylinder. A set of macros to automate the mapping (MapSphere() and 
MapCylinder() for example) might be useful (and would work anywhere you 
need the mapping, not just in the height field macros), but it doesn't 
belong in the height field macros.


> > Look for "spherical height field" and "cylinderical height field"...
> 
> Look where? Where can I find the definitions?

Google popped up a few. Polyray has both as primitives, Virtualight has 
a spherical height field. Fractal Terrains uses spherical height fields 
for planets, and has a nice, simple description: "every latitude, 
longitude position has a radial offset from a perfect sphere". There 
have been utilities that output POV-Ray mesh files for these shapes. 
(Orb and Cyl for example)


> By the way, "cylinderical" is spelled wrong and the wrong spelling seems to
> have made it into the documentation. The correct spelling is "cylindrical".

The spelling "cylinderical" is very commonly used, and is one I 
personally have a hard time avoiding. :-(

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/

Post a reply to this message