Added EdgesHelper

src/extras/helpers/EdgesHelper.js

@@ -0,0 +1,84 @@
+/**
+ * @author WestLangley / http://github.com/WestLangley
+ */
+
+THREE.EdgesHelper = function ( object, hex ) {
+
+	var color = ( hex !== undefined ) ? hex : 0xffffff;
+
+	var edge = [ 0, 0 ], hash = {};
+	var sortFunction = function ( a, b ) { return a - b };
+
+	var keys = [ 'a', 'b', 'c' ];
+	var geometry = new THREE.BufferGeometry();
+
+	var geometry2 = object.geometry.clone();
+
+	geometry2.mergeVertices();
+	geometry2.computeFaceNormals();
+
+	var vertices = geometry2.vertices;
+	var faces = geometry2.faces;
+	var numEdges = 0;
+
+	for ( var i = 0, l = faces.length; i < l; i ++ ) {
+
+		var face = faces[ i ];
+
+		for ( var j = 0; j < 3; j ++ ) {
+
+			edge[ 0 ] = face[ keys[ j ] ];
+			edge[ 1 ] = face[ keys[ ( j + 1 ) % 3 ] ];
+			edge.sort( sortFunction );
+
+			var key = edge.toString();
+
+			if ( hash[ key ] === undefined ) {
+
+				hash[ key ] = { vert1: edge[ 0 ], vert2: edge[ 1 ], face1: i, face2: undefined };
+				numEdges ++;
+
+			} else {
+
+				hash[ key ].face2 = i;
+
+			}
+
+		}
+
+	}
+
+	geometry.addAttribute( 'position', Float32Array, 2 * numEdges, 3 );
+
+	var coords = geometry.attributes.position.array;
+
+	var index = 0;
+
+	for ( var key in hash ) {
+
+		var h = hash[ key ];
+
+		if ( h.face2 === undefined || faces[ h.face1 ].normal.dot( faces[ h.face2 ].normal ) < 0.9999 ) { // hardwired const OK
+
+			var vertex = vertices[ h.vert1 ];
+			coords[ index ++ ] = vertex.x;
+			coords[ index ++ ] = vertex.y;
+			coords[ index ++ ] = vertex.z;
+
+			vertex = vertices[ h.vert2 ];
+			coords[ index ++ ] = vertex.x;
+			coords[ index ++ ] = vertex.y;
+			coords[ index ++ ] = vertex.z;
+
+		}
+
+	}
+
+	THREE.Line.call( this, geometry, new THREE.LineBasicMaterial( { color: color } ), THREE.LinePieces );
+
+	this.matrixAutoUpdate = false;
+	this.matrixWorld = object.matrixWorld;
+
+};
+
+THREE.EdgesHelper.prototype = Object.create( THREE.Line.prototype );

utils/build/includes/extras.json

@@ -48,6 +48,7 @@
 	"src/extras/helpers/BoundingBoxHelper.js",
 	"src/extras/helpers/CameraHelper.js",
 	"src/extras/helpers/DirectionalLightHelper.js",
+	"src/extras/helpers/EdgesHelper.js",
 	"src/extras/helpers/FaceNormalsHelper.js",
 	"src/extras/helpers/GridHelper.js",
 	"src/extras/helpers/HemisphereLightHelper.js",