Examples: Fix use of removed GeometryUtils method.

examples/jsm/utils/GeometryUtils.d.ts

 import {
-	BufferGeometry,
-	Face3,
-	Geometry,
 	Vector3
 } from '../../../src/Three';
 
 export namespace GeometryUtils {
-	/**
-   * @deprecated Use {@link Geometry#merge geometry.merge( geometry2, matrix, materialIndexOffset )} instead.
-   */
-	export function merge( geometry1: Geometry, geometry2: Geometry, materialIndexOffset?: number ): void;
-	/**
-   * @deprecated Use {@link Geometry#center geometry.center()} instead.
-   */
-	export function center( geometry: Geometry ): Geometry;
-
-	export function randomPointInTriangle( vectorA: Vector3, vectorB: Vector3, vectorC: Vector3 ): Vector3;
-	export function randomPointInFace( face: Face3, geometry: Geometry ): Vector3;
-	export function randomPointsInGeometry( geometry: Geometry, n: number ): Vector3[];
-	export function randomPointsInBufferGeometry( geometry: BufferGeometry, n: number ): Vector3[];
-	export function triangleArea( vectorA: Vector3, vectorB: Vector3, vectorC: Vector3 ): number;
 	export function hilbert2D( center?: Vector3, size?: number, iterations?: number, v0?: number, v1?: number, v2?: number, v3?: number ): Vector3[];
 	export function hilbert3D( center?: Vector3, size?: number, iterations?: number, v0?: number, v1?: number, v2?: number, v3?: number, v4?: number, v5?: number, v6?: number, v7?: number ): Vector3[];
 }

examples/webgl_geometry_text.html

@@ -357,6 +357,8 @@
 				textGeo.computeBoundingBox();
 				textGeo.computeVertexNormals();
 
+				var triangle = new THREE.Triangle();
+
 				// "fix" side normals by removing z-component of normals for side faces
 				// (this doesn't work well for beveled geometry as then we lose nice curvature around z-axis)
 
@@ -381,7 +383,7 @@
 							var vb = textGeo.vertices[ face.b ];
 							var vc = textGeo.vertices[ face.c ];
 
-							var s = GeometryUtils.triangleArea( va, vb, vc );
+							var s = triangle.set( va, vb, vc ).getArea();
 
 							if ( s > triangleAreaHeuristics ) {