POV-Ray : Newsgroups : povray.general : Request for Comments: Quadratic Bezier Splines : Request for Comments: Quadratic Bezier Splines Server Time
29 Jul 2021 11:38:29 EDT (-0400)
  Request for Comments: Quadratic Bezier Splines  
From: clipka
Date: 6 Jun 2021 17:52:34
Message: <60bd43a2$1@news.povray.org>
Hi folks,

the `prism` primitive currently supports, among others, cubic Bezier 
spline outlines.

For certain technical reasons, I may need to add support for _quadratic_ 
Bezier splines at the render engine level as well, but it would be a 
waste to not expose them to the scene description language (and, while 
I'm at it, possibly also extend `lathe` accordingly).

An open question is, what keyword should be used for this type of spline?


For the records:

- Quadratic Bezier splines are a flavor of quadratic splines, aka 2nd 
order polynomial splines.

- Quadratic splines are also occasionally referred to as "conic splines" 
or "conic arcs", for reasons I'm not entirely sure of.

- `bezier_spline` is the current moniker for cubic Bezier splines.

- `quadratic_spline` is already in use for some quirky flavor of 
quadratic spline that, in my mind, doesn't even deserve to live, but has 
a long-standing tradition of existing under this moniker and therefore 
isn't going anywhere in POV-Ray v3.x.


Here are some ideas:

- `quadratic_bezier_spline`, being the most accurate term.

- `conic_bezier_spline`, being a bit shorter.

- `conic_spline`, being yet shorter.

- `bezier2_spline`, the "2" referring to the polynomial order.


Personally, I'm somewhat unhappy with the very first for being rather 
verbose, and the third for being prone to confusion with both 
`cubic_spline` and `conic_sweep`, the latter being also used in `prism`. 
I'm also not quite happy with the second one, because it's still 
somewhat lengthy, and I think it isn't the most accurate of terms.


Thoughts, anyone?


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