From 8c63886ba6e84b61499955a89a8011f2cdad1a5d Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@yandex-team.ru>
Date: Sat, 23 May 2020 14:26:40 +0300
Subject: [PATCH] Added a comment

---
 src/Functions/pointInPolygon.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Functions/pointInPolygon.cpp b/src/Functions/pointInPolygon.cpp
index a780989e18..00df42bdc1 100644
--- a/src/Functions/pointInPolygon.cpp
+++ b/src/Functions/pointInPolygon.cpp
@@ -319,6 +319,10 @@ private:
           * - simplicity and performance;
           * - can be additionally speed up with loop unrolling and/or binary search for possible intersecting edges.
           *
+          * Drawbacks:
+          * - it's unspecified whether a point of the edge is inside or outside of a polygon
+          *   (looks like it's inside for "left" edges and outside for "right" edges)
+          *
           * Why not to apply the same algorithm available in boost::geometry?
           * It will require to move data from columns to temporary containers.
           * Despite the fact that the boost library is template based and allows arbitrary containers and points,
-- 
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