Abstract base class of interpolants over parametric samples.
		The parameter domain is one dimensional, typically the time or a path along a curve defined by the data.
		The sample values can have any dimensionality and derived classes may apply special interpretations to the data.
		This class provides the interval seek in a Template Method, deferring the actual interpolation to derived classes.
		Time complexity is *O(1)* for linear access crossing at most two points and *O(log N)* for random access,
		where *N* is the number of positions.
		References:	[link:http://www.oodesign.com/template-method-pattern.html http://www.oodesign.com/template-method-pattern.html]
		
		parameterPositions -- array of positions
		sampleValues -- array of samples
		sampleSize -- number of samples
		resultBuffer -- buffer to store the interpolation results.
		Note: This is not designed to be called directly.
		
Optional, subclass-specific settings structure.
Evaluate the interpolant at position *t*.
[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]