Add difference of regions.

1 files changed, 36 insertions, 0 deletions

diff --git a/geometry/geometry_tests/region2d_binary_op_test.cpp b/geometry/geometry_tests/region2d_binary_op_test.cpp
index f129c24652..47b00095a2 100644
--- a/geometry/geometry_tests/region2d_binary_op_test.cpp
+++ b/geometry/geometry_tests/region2d_binary_op_test.cpp
@@ -42,3 +42,39 @@ UNIT_TEST(RegionIntersect_Smoke)
     TEST_EQUAL(res.size(), 0, ());
   }
 }
+
+UNIT_TEST(RegionDifference_Smoke)
+{
+  {
+    P arr1[] = { P(-1, 1), P(1, 1), P(1, -1), P(-1, -1) };
+    P arr2[] = { P(-2, 2), P(2, 2), P(2, -2), P(-2, -2) };
+
+    R r1, r2;
+    r1.Assign(arr1, arr1 + ARRAY_SIZE(arr1));
+    r2.Assign(arr2, arr2 + ARRAY_SIZE(arr2));
+
+    vector<R> res;
+    m2::DiffRegions(r1, r2, res);
+    TEST_EQUAL(res.size(), 0, ());
+
+    m2::DiffRegions(r2, r1, res);
+
+    TEST_EQUAL(res.size(), 1, ());
+    TEST_EQUAL(res[0].GetRect(), r2.GetRect(), ());
+  }
+
+  {
+    P arr1[] = { P(0, 1), P(2, 1), P(2, 0), P(0, 0) };
+    P arr2[] = { P(1, 2), P(2, 2), P(2, -1), P(1, -1) };
+
+    R r1, r2;
+    r1.Assign(arr1, arr1 + ARRAY_SIZE(arr1));
+    r2.Assign(arr2, arr2 + ARRAY_SIZE(arr2));
+
+    vector<R> res;
+    m2::DiffRegions(r1, r2, res);
+
+    TEST_EQUAL(res.size(), 1, ());
+    TEST_EQUAL(res[0].GetRect(), m2::RectI(0, 0, 1, 1), ());
+  }
+}