webglFramework/Thirdparty/three.js-master/src/extras/curves/SplineCurve.js

   1 import { Curve } from '../core/Curve';
   2 import { CatmullRom } from '../core/Interpolations';
   3 import { Vector2 } from '../../math/Vector2';
   4
   5
   6 function SplineCurve( points /* array of Vector2 */ ) {
   7
   8         Curve.call( this );
   9
  10         this.points = ( points === undefined ) ? [] : points;
  11
  12 }
  13
  14 SplineCurve.prototype = Object.create( Curve.prototype );
  15 SplineCurve.prototype.constructor = SplineCurve;
  16
  17 SplineCurve.prototype.isSplineCurve = true;
  18
  19 SplineCurve.prototype.getPoint = function ( t ) {
  20
  21         var points = this.points;
  22         var point = ( points.length - 1 ) * t;
  23
  24         var intPoint = Math.floor( point );
  25         var weight = point - intPoint;
  26
  27         var point0 = points[ intPoint === 0 ? intPoint : intPoint - 1 ];
  28         var point1 = points[ intPoint ];
  29         var point2 = points[ intPoint > points.length - 2 ? points.length - 1 : intPoint + 1 ];
  30         var point3 = points[ intPoint > points.length - 3 ? points.length - 1 : intPoint + 2 ];
  31
  32         return new Vector2(
  33                 CatmullRom( weight, point0.x, point1.x, point2.x, point3.x ),
  34                 CatmullRom( weight, point0.y, point1.y, point2.y, point3.y )
  35         );
  36
  37 };
  38
  39 export { SplineCurve };