cubic-hermite-spline

Cubic Hermite spline interpolation

Cubic Hermite spline interpolation of points / tangeants in any dimension with optional derivative computation. The interpolator can also take a knot-like vector as an optional parameter, which may be useful to enforce time at control points when used for position / velocity interpolation.

Install

$ npm install cubic-hermite-spline

Example

Basic usage

var hermite = require('cubic-hermite-spline');
 
var points = [
  [-1, 0],
  [ 0, 0],
  [ 1, 0]
];
 
var tangents = [
  [1, 1],
  [0, 1],
  [1, 1]
];
 
for(var t=0; t<1; t+=0.01) {
  var point = hermite(t, points, tangents);
  var tangent = hermite(t, points, tangents, null, true);
}

With a knot vector

var hermite = require('cubic-hermite-spline');
 
var points = [
  [-1, 0],
  [ 0, 0],
  [ 1, 0]
];
 
var tangents = [
  [1, 1],
  [0, 1],
  [1, 1]
];
 
var knots = [
  0, 1.5, 2
];
 
for(var t=0; t<1; t+=0.01) {
  var point = hermite(t, points, tangents);
  var tangent = hermite(t, points, tangents, knots, true);
}

Usage

hermite(t, points, tangents[, knots, derivative, result])

Computes the interpolation at t for the provided set of points and tangents, and optional knots.

• t position along the curve: in the [0, 1] range for regular use, and [0, last-knot-value] when using knots
• points vectors to interpolate
• tangents tangents at provided points
• knots enforced values of t at provided points
• derivative if true return the tangeant at t instead of the position
• result preallocated array in which the result will be stored (avoid GC)

Returns the interpolated vector