Minor fix in AKSceneTracker6DOF

Summary: In the normals of a triangles are invalid, we need to ensure that we are testing the replacement triangle (from the back) as in the next loop (and not skipping it).

Reviewed By: enpe

Differential Revision: D64418240

fbshipit-source-id: b5143d617b8119bd2498892dfb01f3f6b0fd9fc9

impl/ocean/devices/arkit/AKSceneTracker6DOF.mm

@@ -285,7 +285,7 @@
 
 					// ARKit sometimes provides invalid per-vertex normals, we remove these triangles
 
-					for (size_t n = 0; n < triangleIndices.size(); n += 3)
+					for (size_t n = 0; n < triangleIndices.size(); /*noop*/)
 					{
 						if (Numeric::isNan(perVertexNormals[triangleIndices[n + 0]].x())
 								|| Numeric::isNan(perVertexNormals[triangleIndices[n + 1]].x())
@@ -297,6 +297,10 @@
 
 							triangleIndices.resize(triangleIndices.size() - 3);
 						}
+						else
+						{
+							n += 3;
+						}
 					}
 
 					if (!triangleIndices.empty())