99 lines
2.6 KiB
JavaScript
99 lines
2.6 KiB
JavaScript
import {
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Vector4
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} from 'three';
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import * as NURBSUtils from '../curves/NURBSUtils.js';
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/**
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* This class represents a NURBS surface.
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*
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* Implementation is based on `(x, y [, z=0 [, w=1]])` control points with `w=weight`.
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*
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* @three_import import { NURBSSurface } from 'three/addons/curves/NURBSSurface.js';
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*/
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class NURBSSurface {
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/**
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* Constructs a new NURBS surface.
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*
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* @param {number} degree1 - The first NURBS degree.
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* @param {number} degree2 - The second NURBS degree.
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* @param {Array<number>} knots1 - The first knots as a flat array of numbers.
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* @param {Array<number>} knots2 - The second knots as a flat array of numbers.
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* @param {Array<Array<Vector2|Vector3|Vector4>>} controlPoints - An array^2 holding control points.
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*/
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constructor( degree1, degree2, knots1, knots2, controlPoints ) {
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/**
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* The first NURBS degree.
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*
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* @type {number}
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*/
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this.degree1 = degree1;
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/**
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* The second NURBS degree.
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*
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* @type {number}
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*/
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this.degree2 = degree2;
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/**
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* The first knots as a flat array of numbers.
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*
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* @type {Array<number>}
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*/
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this.knots1 = knots1;
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/**
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* The second knots as a flat array of numbers.
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*
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* @type {Array<number>}
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*/
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this.knots2 = knots2;
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/**
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* An array holding arrays of control points.
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*
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* @type {Array<Array<Vector2|Vector3|Vector4>>}
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*/
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this.controlPoints = [];
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const len1 = knots1.length - degree1 - 1;
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const len2 = knots2.length - degree2 - 1;
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// ensure Vector4 for control points
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for ( let i = 0; i < len1; ++ i ) {
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this.controlPoints[ i ] = [];
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for ( let j = 0; j < len2; ++ j ) {
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const point = controlPoints[ i ][ j ];
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this.controlPoints[ i ][ j ] = new Vector4( point.x, point.y, point.z, point.w );
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}
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}
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}
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/**
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* This method returns a vector in 3D space for the given interpolation factor. This vector lies on the NURBS surface.
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*
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* @param {number} t1 - The first interpolation factor representing the `u` position on the surface. Must be in the range `[0,1]`.
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* @param {number} t2 - The second interpolation factor representing the `v` position on the surface. Must be in the range `[0,1]`.
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* @param {Vector3} target - The target vector the result is written to.
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*/
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getPoint( t1, t2, target ) {
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const u = this.knots1[ 0 ] + t1 * ( this.knots1[ this.knots1.length - 1 ] - this.knots1[ 0 ] ); // linear mapping t1->u
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const v = this.knots2[ 0 ] + t2 * ( this.knots2[ this.knots2.length - 1 ] - this.knots2[ 0 ] ); // linear mapping t2->u
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NURBSUtils.calcSurfacePoint( this.degree1, this.degree2, this.knots1, this.knots2, this.controlPoints, u, v, target );
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}
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}
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export { NURBSSurface };
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