Java Reference
In-Depth Information
Again, after applying the constraints imposed by implementing an interpolator, the function can be
thought of as:
ax
3
+ bx
2
+ cx = 1
The code in Listing 5-6 implements an interpolator based on the cubic function.
Listing 5-6.
CubicInterpolator.fx
public class CubicInterpolator extends SimpleInterpolator {
public var a = 1.0 on replace{
c = 1.0 - a -b;
}
public var b = 1.0 on replace{
c = 1.0 - a -b;
}
var c:Number = 1.0 - a -b;
public override function curve(fraction:Number):Number{
return (a*fraction*fraction*fraction + b*fraction*fraction + c*fraction);
}
}
The implementation of the
CubicInterpolator
in Listing 5-6 looks a lot like the
QuadraticInterpolator
—the coefficients
a
and
b
can be set, while the coefficient
c
is solved for. The
function
curve
simply adds up the terms. A cubic function was used to produce the curve in Figure 5-5,
which shows the signature up and down wave pattern that identifies a cubic function.
