1 ! Copyright (C) 2010 Erik Charlebois
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: accessors combinators kernel locals math math.combinatorics
4 math.polynomials opengl.gl sequences ui.gadgets ui.gadgets.panes
5 ui.render arrays grouping math.vectors assocs
7 FROM: sequences => change-nth ;
11 :: bernstein-polynomial-ith ( n i -- p )
12 n i nCk { 0 1 } i p^ { 1 -1 } n i - p^ p* n*p ;
14 :: hermite-polynomial ( p0 m0 p1 m1 -- poly )
17 -3 p0 * -2 m0 * + 3 p1 * + m1 neg +
18 2 p0 * m0 + -2 p1 * + m1 +
21 :: kochanek-bartels-coefficients ( tension bias continuity -- s1 d1 s2 d2 )
25 [ 1 continuity + * * 2 / ]
26 [ 1 continuity - * * 2 / ] 2bi
30 [ 1 continuity - * * 2 / ]
31 [ 1 continuity + * * 2 / ] 2bi
34 :: kochanek-bartels-tangents ( points m0 mn c1 c2 -- tangents )
36 first3 :> ( pi-1 pi pi+1 )
44 :: <bezier-curve> ( control-points -- polynomials )
47 [ first length [ { 0 } ] replicate ]
50 control-points [| pt i |
51 n i bernstein-polynomial-ith :> poly
53 j acc [ v poly n*p p+ ] change-nth
58 :: <cubic-hermite-curve> ( p0 m0 p1 m1 -- polynomials )
68 : (cubic-hermite-spline) ( point-in-out-triplets -- polynomials-sequence )
70 first2 [ first2 ] [ [ first ] [ third ] bi ] bi* <cubic-hermite-curve>
74 : <cubic-hermite-spline> ( point-tangent-pairs -- polynomials-sequence )
75 2 clump [ first2 [ first2 ] bi@ <cubic-hermite-curve> ] map ;
77 :: <kochanek-bartels-curve> ( points m0 mn tension bias continuity -- polynomials-sequence )
78 tension bias continuity kochanek-bartels-coefficients :> ( s1 d1 s2 d2 )
80 [ s1 s2 kochanek-bartels-tangents ]
81 [ d1 d2 kochanek-bartels-tangents ] 3bi :> ( in out )
82 points in out [ 3array ] 3map (cubic-hermite-spline) ;
84 : <catmull-rom-spline> ( points m0 mn -- polynomials-sequence )
85 0 0 0 <kochanek-bartels-curve> ;