first commit

geometries.js

@@ -0,0 +1,201 @@
+import * as THREE from 'three';
+import { ConvexHull } from 'three/addons/math/ConvexHull.js';
+
+const {BufferGeometry, Float32BufferAttribute, Vector3} = THREE;
+
+export class ConvexGeometry extends BufferGeometry {
+
+	constructor( points = [] ) {
+      super();
+      this.convexHull = new ConvexHull();
+      this.setFromPoints(points);
+    }
+
+    setFromPoints(points) {
+        const {convexHull} = this;
+
+        convexHull.setFromPoints(points);
+		// buffers
+
+		const vertices = [];
+		const normals = [];
+
+		// generate vertices and normals
+
+		const faces = convexHull.faces;
+
+		for ( let i = 0; i < faces.length; i ++ ) {
+
+			const face = faces[ i ];
+			let edge = face.edge;
+
+			// we move along a doubly-connected edge list to access all face points (see HalfEdge docs)
+
+			do {
+
+				const point = edge.head().point;
+
+				vertices.push( point.x, point.y, point.z );
+				normals.push( face.normal.x, face.normal.y, face.normal.z );
+
+				edge = edge.next;
+
+			} while ( edge !== face.edge );
+
+		}
+
+		// build geometry
+
+		this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
+		this.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );
+
+	}
+
+}
+
+export class WireframeGeometry extends BufferGeometry {
+
+	constructor( geometry = null ) {
+
+		super();
+
+		this.type = 'WireframeGeometry';
+
+		this.parameters = {
+			geometry: geometry
+		};
+
+      this.update();
+    }
+
+    update() {
+        const {geometry} = this.parameters;
+
+		if ( geometry !== null ) {
+
+			// buffer
+
+			const vertices = [];
+			const edges = new Set();
+
+			// helper variables
+
+			const start = new Vector3();
+			const end = new Vector3();
+
+			if ( geometry.index !== null ) {
+
+				// indexed BufferGeometry
+
+				const position = geometry.attributes.position;
+				const indices = geometry.index;
+				let groups = geometry.groups;
+
+				if ( groups.length === 0 ) {
+
+					groups = [ { start: 0, count: indices.count, materialIndex: 0 } ];
+
+				}
+
+				// create a data structure that contains all edges without duplicates
+
+				for ( let o = 0, ol = groups.length; o < ol; ++ o ) {
+
+					const group = groups[ o ];
+
+					const groupStart = group.start;
+					const groupCount = group.count;
+
+					for ( let i = groupStart, l = ( groupStart + groupCount ); i < l; i += 3 ) {
+
+						for ( let j = 0; j < 3; j ++ ) {
+
+							const index1 = indices.getX( i + j );
+							const index2 = indices.getX( i + ( j + 1 ) % 3 );
+
+							start.fromBufferAttribute( position, index1 );
+							end.fromBufferAttribute( position, index2 );
+
+							if ( isUniqueEdge( start, end, edges ) === true ) {
+
+								vertices.push( start.x, start.y, start.z );
+								vertices.push( end.x, end.y, end.z );
+
+							}
+
+						}
+
+					}
+
+				}
+
+			} else {
+
+				// non-indexed BufferGeometry
+
+				const position = geometry.attributes.position;
+
+				for ( let i = 0, l = ( position.count / 3 ); i < l; i ++ ) {
+
+					for ( let j = 0; j < 3; j ++ ) {
+
+						// three edges per triangle, an edge is represented as (index1, index2)
+						// e.g. the first triangle has the following edges: (0,1),(1,2),(2,0)
+
+						const index1 = 3 * i + j;
+						const index2 = 3 * i + ( ( j + 1 ) % 3 );
+
+						start.fromBufferAttribute( position, index1 );
+						end.fromBufferAttribute( position, index2 );
+
+						if ( isUniqueEdge( start, end, edges ) === true ) {
+
+							vertices.push( start.x, start.y, start.z );
+							vertices.push( end.x, end.y, end.z );
+
+						}
+
+					}
+
+				}
+
+			}
+
+			// build geometry
+
+			this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
+
+		}
+
+	}
+
+	copy( source ) {
+
+		super.copy( source );
+
+		this.parameters = Object.assign( {}, source.parameters );
+
+		return this;
+
+	}
+
+}
+
+export function isUniqueEdge( start, end, edges ) {
+
+	const hash1 = `${start.x},${start.y},${start.z}-${end.x},${end.y},${end.z}`;
+	const hash2 = `${end.x},${end.y},${end.z}-${start.x},${start.y},${start.z}`; // coincident edge
+
+	if ( edges.has( hash1 ) === true || edges.has( hash2 ) === true ) {
+
+		return false;
+
+	} else {
+
+		edges.add( hash1 );
+		edges.add( hash2 );
+		return true;
+
+	}
+
+}