three 基础库
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( function () {
/**
* NURBS surface object
*
* Implementation is based on (x, y [, z=0 [, w=1]]) control points with w=weight.
**/
class NURBSSurface {
constructor( degree1, degree2, knots1, knots2
/* arrays of reals */
, controlPoints
/* array^2 of Vector(2|3|4) */
) {
this.degree1 = degree1;
this.degree2 = degree2;
this.knots1 = knots1;
this.knots2 = knots2;
this.controlPoints = [];
const len1 = knots1.length - degree1 - 1;
const len2 = knots2.length - degree2 - 1; // ensure THREE.Vector4 for control points
for ( let i = 0; i < len1; ++ i ) {
this.controlPoints[ i ] = [];
for ( let j = 0; j < len2; ++ j ) {
const point = controlPoints[ i ][ j ];
this.controlPoints[ i ][ j ] = new THREE.Vector4( point.x, point.y, point.z, point.w );
}
}
}
getPoint( t1, t2, target ) {
const u = this.knots1[ 0 ] + t1 * ( this.knots1[ this.knots1.length - 1 ] - this.knots1[ 0 ] ); // linear mapping t1->u
const v = this.knots2[ 0 ] + t2 * ( this.knots2[ this.knots2.length - 1 ] - this.knots2[ 0 ] ); // linear mapping t2->u
THREE.NURBSUtils.calcSurfacePoint( this.degree1, this.degree2, this.knots1, this.knots2, this.controlPoints, u, v, target );
}
}
THREE.NURBSSurface = NURBSSurface;
} )();