mirror of
https://github.com/Doodle3D/Doodle3D-Slicer.git
synced 2024-07-08 11:40:43 +02:00
58 lines
1.6 KiB
JavaScript
Executable File
58 lines
1.6 KiB
JavaScript
Executable File
/**
|
|
* @author renej
|
|
* 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.
|
|
*
|
|
**/
|
|
|
|
|
|
/**************************************************************
|
|
* NURBS curve
|
|
**************************************************************/
|
|
|
|
THREE.NURBSCurve = function ( degree, knots /* array of reals */, controlPoints /* array of Vector(2|3|4) */) {
|
|
|
|
this.degree = degree;
|
|
this.knots = knots;
|
|
this.controlPoints = [];
|
|
for (var i = 0; i < controlPoints.length; ++ i) { // ensure Vector4 for control points
|
|
var point = controlPoints[i];
|
|
this.controlPoints[i] = new THREE.Vector4(point.x, point.y, point.z, point.w);
|
|
}
|
|
|
|
};
|
|
|
|
|
|
THREE.NURBSCurve.prototype = Object.create( THREE.Curve.prototype );
|
|
THREE.NURBSCurve.prototype.constructor = THREE.NURBSCurve;
|
|
|
|
|
|
THREE.NURBSCurve.prototype.getPoint = function ( t ) {
|
|
|
|
var u = this.knots[0] + t * (this.knots[this.knots.length - 1] - this.knots[0]); // linear mapping t->u
|
|
|
|
// following results in (wx, wy, wz, w) homogeneous point
|
|
var hpoint = THREE.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 new THREE.Vector3(hpoint.x, hpoint.y, hpoint.z);
|
|
};
|
|
|
|
|
|
THREE.NURBSCurve.prototype.getTangent = function ( t ) {
|
|
|
|
var u = this.knots[0] + t * (this.knots[this.knots.length - 1] - this.knots[0]);
|
|
var ders = THREE.NURBSUtils.calcNURBSDerivatives(this.degree, this.knots, this.controlPoints, u, 1);
|
|
var tangent = ders[1].clone();
|
|
tangent.normalize();
|
|
|
|
return tangent;
|
|
};
|
|
|