POV-Ray : Newsgroups : povray.general : Request for Comments: Quadratic Bezier Splines : Re: Request for Comments: Quadratic Bezier Splines Server Time
16 Jun 2021 15:49:02 EDT (-0400)
  Re: Request for Comments: Quadratic Bezier Splines  
From: Bald Eagle
Date: 6 Jun 2021 18:45:00
Message: <web.60bd4ee884e2d21b1f9dae3025979125@news.povray.org>
clipka <ano### [at] anonymousorg> wrote:
> 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).

> <snip>

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

> Thoughts, anyone?


thoughts:


used in fonts/typfaces and svg representations of glyphs.  Cousin Ricky was nice
enough to provide me with an early release of his sphere sweep macro that allows
QBS.


degree.

So, you may not have to code a whole separate section for QBS - just write an
algorithm to degree-elevate a QBS to a cubic.  I have my SDL version that you
can have to adapt into suitable c++ source code.

IIRC degree reduction was a bit trickier, and I hadn't implemented that.

maybe he already has something to do that side of the degree manipulation.

What would be very nice would be a generic "bezier" keyword followed by the
desired degree, or perhaps, by the degree of the supplied control points
followed by the desired degree after elevation / reduction.

But that is JUST something to think about, before anything becomes "concrete".


Does that help?  :D


Post a reply to this message

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.