From 0cb197a6c4fb07925f850c9af232bf6d73601e2a Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Sun, 19 Jun 2022 22:25:56 +0300
Subject: [PATCH] Fix geom::intersection(segment,box) for axis-aligned segments

---
 libs/geom/include/psemek/geom/intersection.hpp | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/libs/geom/include/psemek/geom/intersection.hpp b/libs/geom/include/psemek/geom/intersection.hpp
index 100b8702..72a85e00 100644
--- a/libs/geom/include/psemek/geom/intersection.hpp
+++ b/libs/geom/include/psemek/geom/intersection.hpp
@@ -139,12 +139,20 @@ namespace psemek::geom
 
 		for (std::size_t i = 0; i < N; ++i)
 		{
-			T tmin = (b[i].min - s[0][i]) / (s[1][i] - s[0][i]);
-			T tmax = (b[i].max - s[0][i]) / (s[1][i] - s[0][i]);
+			if (s[1][i] != s[0][i])
+			{
+				T tmin = (b[i].min - s[0][i]) / (s[1][i] - s[0][i]);
+				T tmax = (b[i].max - s[0][i]) / (s[1][i] - s[0][i]);
 
-			if (tmin > tmax) std::swap(tmin, tmax);
+				if (tmin > tmax) std::swap(tmin, tmax);
 
-			t &= interval<T>{tmin, tmax};
+				t &= interval<T>{tmin, tmax};
+			}
+			else
+			{
+				if (!contains(b[i], s[0][i]))
+					return interval<T>{};
+			}
 		}
 
 		return t;