LineSegments: Added .computeLineDistances()

src/objects/Line.js

@@ -65,7 +65,7 @@ Line.prototype = Object.assign( Object.create( Object3D.prototype ), {
 
 						}
 
-						lineDistances.push( distance );
+						lineDistances[ i ] = distance;
 
 					}
 

src/objects/LineSegments.js

@@ -1,4 +1,5 @@
 import { Line } from './Line.js';
+import { Vector3 } from '../math/Vector3.js';
 
 /**
  * @author mrdoob / http://mrdoob.com/
@@ -16,7 +17,70 @@ LineSegments.prototype = Object.assign( Object.create( Line.prototype ), {
 
 	constructor: LineSegments,
 
-	isLineSegments: true
+	isLineSegments: true,
+
+	computeLineDistances: ( function () {
+
+		var start = new Vector3();
+		var end = new Vector3();
+
+		return function computeLineDistances() {
+
+			var distance = 0;
+			var geometry = this.geometry;
+
+			if ( geometry.isBufferGeometry ) {
+
+				// we assume non-indexed geometry
+
+				if ( geometry.index === null ) {
+
+					var positionAttribute = geometry.attributes.position;
+					var lineDistances = [];
+
+					for ( var i = 0, l = positionAttribute.count; i < l; i += 2 ) {
+
+						start.fromBufferAttribute( positionAttribute, i );
+						end.fromBufferAttribute( positionAttribute, i + 1 );
+
+						distance += start.distanceTo( end );
+
+						lineDistances[ i ] = ( i === 0 ) ? 0 : lineDistances[ i - 1 ];
+						lineDistances[ i + 1 ] = distance;
+
+					}
+
+					geometry.addAttribute( 'lineDistance', new THREE.Float32BufferAttribute( lineDistances, 1 ) );
+
+				} else {
+
+					console.warn( 'THREE.Line.computeLineDistances(): Computation only possible with non-indexed BufferGeometry.' );
+
+				}
+
+			} else if ( geometry.isGeometry ) {
+
+				var vertices = geometry.vertices;
+
+				for ( var i = 0, l = vertices.length; i < l; i += 2 ) {
+
+					start.copy( vertices[ i ] );
+					end.copy( vertices[ i + 1 ] );
+
+					distance += start.distanceTo( end );
+
+					geometry.lineDistances[ i ] = ( i === 0 ) ? 0 : geometry.lineDistances[ i - 1 ];
+					geometry.lineDistances[ i + 1 ] = distance;
+
+				}
+
+			}
+
+			return this;
+
+		};
+
+	}() )
 
 } );