73 lines
1.7 KiB
JavaScript
73 lines
1.7 KiB
JavaScript
import {
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BufferGeometry,
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Float32BufferAttribute
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} from 'three';
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import { ConvexHull } from '../math/ConvexHull.js';
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/**
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* This class can be used to generate a convex hull for a given array of 3D points.
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* The average time complexity for this task is considered to be O(nlog(n)).
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*
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* ```js
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* const geometry = new ConvexGeometry( points );
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* const material = new THREE.MeshBasicMaterial( { color: 0x00ff00 } );
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* const mesh = new THREE.Mesh( geometry, material );
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* scene.add( mesh );
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* ```
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*
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* @augments BufferGeometry
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* @three_import import { ConvexGeometry } from 'three/addons/geometries/ConvexGeometry.js';
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*/
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class ConvexGeometry extends BufferGeometry {
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/**
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* Constructs a new convex geometry.
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*
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* @param {Array<Vector3>} points - An array of points in 3D space which should be enclosed by the convex hull.
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*/
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constructor( points = [] ) {
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super();
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// buffers
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const vertices = [];
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const normals = [];
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const convexHull = new ConvexHull().setFromPoints( points );
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// generate vertices and normals
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const faces = convexHull.faces;
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for ( let i = 0; i < faces.length; i ++ ) {
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const face = faces[ i ];
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let edge = face.edge;
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// we move along a doubly-connected edge list to access all face points (see HalfEdge docs)
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do {
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const point = edge.head().point;
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vertices.push( point.x, point.y, point.z );
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normals.push( face.normal.x, face.normal.y, face.normal.z );
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edge = edge.next;
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} while ( edge !== face.edge );
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}
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// build geometry
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this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
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this.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );
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}
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}
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export { ConvexGeometry };
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