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Text File  |  1990-03-07  |  455 b   |  19 lines
  1. {
  2.     Cubic Basis Functions
  3. }
  4.  
  5. bezier(p1, p2, p3, p4, t) =     p1 * (1+t*(-3+t*(3-t))) +
  6.                 p2 * 3*t*(1+t*(-2+t)) +
  7.                 p3 * 3*t*t*(1-t) +
  8.                 p4 * t*t*t ;
  9.  
  10. hermite(p0, p1, r0, r1, t) =    p0 * ((2*t-3)*t*t+1) +
  11.                 p1 * (-2*t+3)*t*t +
  12.                 r0 * (((t-2)*t+1)*t) +
  13.                 r1 * ((t-1)*t*t);
  14.  
  15. bspline(pp, p0, p1, pn, t) =    pp * (1/6+t*(-1/2+t*(1/2-1/6*t))) +
  16.                 p0 * (2/3+t*t*(-1+1/2*t)) +
  17.                 p1 * (1/6+t*(1/2+t*(1/2-1/2*t))) +
  18.                 pn * (1/6*t*t*t) ;
  19.