> From: Raul Miller <[EMAIL PROTECTED]> > > I am trying to come up to speed on NURBS (non-uniform rational b-splines), > and I noticed that we have a couple J OpenGL demos that use NURBS: > http://www.jsoftware.com/jwiki/Studio/OpenGL/Teapot > http://www.jsoftware.com/jwiki/Studio/OpenGL/BraidKnot > > However, I have not found any documentation on NURBS in > the wiki. > > Does anyone have a simple treatment of NURBS, in J?
Just another illustration. J uses an OpenGL NURBS utility http://www.opengl.org/documentation/specs/man_pages/hardcopy/GL/html/glu/nurbssurface.html There is a simpler NURBS demo in Demos|opengl simple. (whose control point generation can be simplified as below) nurbpts=: verb define pts=. '' for_u. i.4 do. for_v. i.4 do. pts=. pts,2*u-1.5 pts=. pts,2*v-1.5 pts=. pts,3*_1^-.(*./(u,v) e. 1 2) end. end. pts ) See also * media/gdiplus, demo 2, curves; a Visio file bezier.vdx, using NURBS() * media/paint uses Bezier to draw curves http://www.jsoftware.com/svn/addons/trunk/media/paint/handlers.ijs ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
