https://github.com/WWBN/AVideo/issues/8713

node_modules/three/examples/jsm/curves/NURBSCurve.js

@@ -0,0 +1,75 @@
+import {
+	Curve,
+	Vector3,
+	Vector4
+} from '../../../build/three.module.js';
+import { NURBSUtils } from '../curves/NURBSUtils.js';
+
+/**
+ * NURBS curve object
+ *
+ * Derives from Curve, overriding getPoint and getTangent.
+ *
+ * Implementation is based on (x, y [, z=0 [, w=1]]) control points with w=weight.
+ *
+ **/
+
+var NURBSCurve = function ( degree, knots /* array of reals */, controlPoints /* array of Vector(2|3|4) */, startKnot /* index in knots */, endKnot /* index in knots */ ) {
+
+	Curve.call( this );
+
+	this.degree = degree;
+	this.knots = knots;
+	this.controlPoints = [];
+	// Used by periodic NURBS to remove hidden spans
+	this.startKnot = startKnot || 0;
+	this.endKnot = endKnot || ( this.knots.length - 1 );
+	for ( var i = 0; i < controlPoints.length; ++ i ) {
+
+		// ensure Vector4 for control points
+		var point = controlPoints[ i ];
+		this.controlPoints[ i ] = new Vector4( point.x, point.y, point.z, point.w );
+
+	}
+
+};
+
+
+NURBSCurve.prototype = Object.create( Curve.prototype );
+NURBSCurve.prototype.constructor = NURBSCurve;
+
+
+NURBSCurve.prototype.getPoint = function ( t, optionalTarget ) {
+
+	var point = optionalTarget || new Vector3();
+
+	var u = this.knots[ this.startKnot ] + t * ( this.knots[ this.endKnot ] - this.knots[ this.startKnot ] ); // linear mapping t->u
+
+	// following results in (wx, wy, wz, w) homogeneous point
+	var hpoint = NURBSUtils.calcBSplinePoint( this.degree, this.knots, this.controlPoints, u );
+
+	if ( hpoint.w != 1.0 ) {
+
+		// project to 3D space: (wx, wy, wz, w) -> (x, y, z, 1)
+		hpoint.divideScalar( hpoint.w );
+
+	}
+
+	return point.set( hpoint.x, hpoint.y, hpoint.z );
+
+};
+
+
+NURBSCurve.prototype.getTangent = function ( t, optionalTarget ) {
+
+	var tangent = optionalTarget || new Vector3();
+
+	var u = this.knots[ 0 ] + t * ( this.knots[ this.knots.length - 1 ] - this.knots[ 0 ] );
+	var ders = NURBSUtils.calcNURBSDerivatives( this.degree, this.knots, this.controlPoints, u, 1 );
+	tangent.copy( ders[ 1 ] ).normalize();
+
+	return tangent;
+
+};
+
+export { NURBSCurve };