cubic-hermite-spline

cubic-hermite-spline
====================

$3

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
-------

``bash
$ npm install cubic-hermite-spline
`

Example
-------

Basic usage

`javascript
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

`javascript
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
-----

$3

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