From ffa039a8498e214d4e8375d46c04fc11829eab43 Mon Sep 17 00:00:00 2001
From: vng <viktor.govako@gmail.com>
Date: Fri, 10 Jun 2011 23:18:19 +0300
Subject: [PATCH] Minor code fixes for Rect-Point intersection.

---
 geometry/geometry_tests/intersect_test.cpp | 59 +++++++++++++++++++---
 geometry/rect_intersect.hpp                | 28 +++++-----
 2 files changed, 63 insertions(+), 24 deletions(-)

diff --git a/geometry/geometry_tests/intersect_test.cpp b/geometry/geometry_tests/intersect_test.cpp
index 803b5a1b33..052e09334a 100644
--- a/geometry/geometry_tests/intersect_test.cpp
+++ b/geometry/geometry_tests/intersect_test.cpp
@@ -9,8 +9,14 @@
 
 #include "../../base/start_mem_debug.hpp"
 
+
 using namespace test;
 
+namespace
+{
+  typedef m2::PointD P;
+}
+
 m2::PointD get_point(m2::RectD const & r, int ind)
 {
   switch (ind % 4)
@@ -25,7 +31,7 @@ m2::PointD get_point(m2::RectD const & r, int ind)
   }
 }
 
-void make_section_longer(m2::PointD & p1, m2::PointD & p2, double sm = 10.0)
+void make_section_longer(m2::PointD & p1, m2::PointD & p2, double sm)
 {
   if (p1.x == p2.x)
   {
@@ -54,20 +60,17 @@ void check_full_equal(m2::RectD const & r, m2::PointD const & p1, m2::PointD con
 {
   m2::PointD pp1 = p1;
   m2::PointD pp2 = p2;
-  make_section_longer(pp1, pp2);
+  make_section_longer(pp1, pp2, 1000.0);
 
   TEST(m2::Intersect(r, pp1, pp2), ());
   TEST(comp(pp1, p1) && comp(pp2, p2), ());
 }
 
-void check_inside(m2::RectD const & r, m2::PointD p1, m2::PointD p2)
+void check_inside(m2::RectD const & r, m2::PointD const & p1, m2::PointD const & p2)
 {
-  double const sm = p1.Length(p2) / 4.0;
-  make_section_longer(p1, p2, -sm);
-
   m2::PointD pp1 = p1;
   m2::PointD pp2 = p2;
-  TEST(m2::Intersect(r, p1, p2), ());
+  TEST(m2::Intersect(r, pp1, pp2), ());
   TEST((pp1 == p1) && (pp2 == p2), ());
 }
 
@@ -120,7 +123,7 @@ void check_eps_boundaries(m2::RectD const & r, double eps = 1.0E-6)
     check_inside(r, get_point(rr, i), get_point(rr, i+1));
 }
 
-UNIT_TEST(IntersectRectSection)
+UNIT_TEST(IntersectRect_Section)
 {
   m2::RectD r(-1, -1, 2, 2);
   check_intersect_boundaries(r);
@@ -128,3 +131,43 @@ UNIT_TEST(IntersectRectSection)
   check_sides(r);
   check_eps_boundaries(r);
 }
+
+namespace 
+{
+  void check_point_in_rect(m2::RectD const & r, m2::PointD const & p)
+  {
+    m2::PointD p1 = p;
+    m2::PointD p2 = p;
+
+    TEST(m2::Intersect(r, p1, p2), ());
+    TEST(p == p1 && p == p2, ());
+  }
+}
+
+UNIT_TEST(IntersectRect_Point)
+{
+  {
+    m2::RectD r(-100, -100, 200, 200);
+    for (int i = 0; i < 4; ++i)
+    {
+      check_point_in_rect(r, get_point(r, i));
+      check_point_in_rect(r, (get_point(r, i) + get_point(r, i+1)) / 2.0);
+    }
+  }
+
+  {
+    m2::RectD r(-1000, -1000, 1000, 1000);
+    double const eps = 1.0E-6;
+    P sm[] = { P(-eps, -eps), P(-eps, eps), P(eps, eps), P(eps, -eps) };
+    for (int i = 0; i < 4; ++i)
+    {
+      P p1 = get_point(r, i);
+      P p2 = p1 - sm[i];
+      check_inside(r, p1, p2);
+
+      p1 = p1 + sm[i];
+      p2 = p1 + sm[i];
+      TEST(!m2::Intersect(r, p1, p2), ());
+    }
+  }
+}
diff --git a/geometry/rect_intersect.hpp b/geometry/rect_intersect.hpp
index e3c8e731e8..2897b8f772 100644
--- a/geometry/rect_intersect.hpp
+++ b/geometry/rect_intersect.hpp
@@ -25,13 +25,12 @@ namespace m2
   template <class T>
   bool Intersect(m2::Rect<T> const & r, m2::Point<T> & p1, m2::Point<T> & p2)
   {
-    int code1 = detail::vcode(r, p1);
-    int code2 = detail::vcode(r, p2);
+    int code[2] = { detail::vcode(r, p1), detail::vcode(r, p2) };
 
     // пока одна из точек отрезка вне прямоугольника
-    while (code1 || code2)
+    while (code[0] || code[1])
     {
-      if (code1 & code2)
+      if (code[0] & code[1])
       {
         // если обе точки с одной стороны прямоугольника, то отрезок не пересекает прямоугольник
         return false;
@@ -39,26 +38,26 @@ namespace m2
 
       // выбираем точку c с ненулевым кодом
       m2::Point<T> * pp;
-      int code;
-      if (code1)
+      int i;
+      if (code[0])
       {
-        code = code1;
+        i = 0;
         pp = &p1;
       }
       else
       {
-        code = code2;
+        i = 1;
         pp = &p2;
       }
 
       // если pp левее r, то передвигаем pp на прямую x = r->x_min
       // если pp правее r, то передвигаем pp на прямую x = r->x_max
-      if (code & detail::LEFT)
+      if (code[i] & detail::LEFT)
       {
         pp->y += (p1.y - p2.y) * (r.minX() - pp->x) / (p1.x - p2.x);
         pp->x = r.minX();
       }
-      else if (code & detail::RIGHT)
+      else if (code[i] & detail::RIGHT)
       {
         pp->y += (p1.y - p2.y) * (r.maxX() - pp->x) / (p1.x - p2.x);
         pp->x = r.maxX();
@@ -66,22 +65,19 @@ namespace m2
 
       // если pp ниже r, то передвигаем pp на прямую y = r->y_min
       // если pp выше r, то передвигаем pp на прямую y = r->y_max
-      if (code & detail::BOT)
+      if (code[i] & detail::BOT)
       {
         pp->x += (p1.x - p2.x) * (r.minY() - pp->y) / (p1.y - p2.y);
         pp->y = r.minY();
       }
-      else if (code & detail::TOP)
+      else if (code[i] & detail::TOP)
       {
         pp->x += (p1.x - p2.x) * (r.maxY() - pp->y) / (p1.y - p2.y);
         pp->y = r.maxY();
       }
 
       // обновляем код
-      if (code == code1)
-        code1 = detail::vcode(r, p1);
-      else
-        code2 = detail::vcode(r, p2);
+      code[i] = detail::vcode(r, *pp);
     }
 
     // оба кода равны 0, следовательно обе точки в прямоугольнике