优化:避免错误

src/Geometry/ExtrudeEdgeGeometry.ts

@@ -14,6 +14,7 @@ export function GenerateExtrudeEdgeGeometry(contourPoints: Vector3[][], height:
 
 function GenerateExtrudeEdgeGeometryPoints(contourPoints: Vector3[], height: number): Vector3[]
 {
+    if (contourPoints.length < 3) return [];
     if (equalv3(contourPoints[0], arrayLast(contourPoints)))
         contourPoints.pop();
     let pts: Vector3[] = [];