Merge pull request #20 from ichiro-its/19-add-support-for-dot-product-and-cross-product

Add Supoort for Dot Product and Cross Product

Author: threeal

include/keisan/point_2.hpp

@@ -49,6 +49,8 @@ struct Point2
 
   static double distance_between(Point2 & point_a, Point2 & point_b);
   static double angle_between(Point2 & point_a, Point2 & point_b);
+  static double dot_product(Point2 & point_a, Point2 & point_b);
+  static double cross_product(Point2 & point_a, Point2 & point_b);
 
   double magnitude();
   double direction();

include/keisan/point_3.hpp

@@ -49,6 +49,8 @@ struct Point3
 
   static double distance_between(Point3 & point_a, Point3 & point_b);
   static double angle_between(Point3 & point_a, Point3 & point_b);
+  static double dot_product(Point3 & point_a, Point3 & point_b);
+  static double cross_product(Point3 & point_a, Point3 & point_b);
 
   double magnitude();
   double direction();

src/point_2.cpp

@@ -140,10 +140,20 @@ double Point2::distance_between(Point2 & point_a, Point2 & point_b)
 
 double Point2::angle_between(Point2 & point_a, Point2 & point_b)
 {
-  double dot_product = point_a.x * point_b.x + point_a.y * point_b.y;
+  double dot = dot_product(point_a, point_b);
   double mag = point_a.magnitude() * point_b.magnitude();
 
-  return wrap_rad(acos(dot_product / mag));
+  return wrap_rad(acos(dot / mag));
+}
+
+double Point2::dot_product(Point2 & point_a, Point2 & point_b)
+{
+  return point_a.x * point_b.x + point_a.y * point_b.y;
+}
+
+double Point2::cross_product(Point2 & point_a, Point2 & point_b)
+{
+  return point_a.magnitude() * point_b.magnitude() * sin(angle_between(point_a, point_b));
 }
 
 double Point2::magnitude()

src/point_3.cpp

@@ -151,10 +151,20 @@ double Point3::distance_between(Point3 & point_a, Point3 & point_b)
 
 double Point3::angle_between(Point3 & point_a, Point3 & point_b)
 {
-  double dot_product = point_a.x * point_b.x + point_a.y * point_b.y + point_a.z * point_b.z;
+  double dot = dot_product(point_a, point_b);
   double mag = point_a.magnitude() * point_b.magnitude();
 
-  return wrap_rad(acos(dot_product / mag));
+  return wrap_rad(acos(dot / mag));
+}
+
+double Point3::dot_product(Point3 & point_a, Point3 & point_b)
+{
+  return point_a.x * point_b.x + point_a.y * point_b.y + point_a.z * point_b.z;
+}
+
+double Point3::cross_product(Point3 & point_a, Point3 & point_b)
+{
+  return point_a.magnitude() * point_b.magnitude() * sin(angle_between(point_a, point_b));
 }
 
 double Point3::magnitude()

test/point_2_test.cpp

@@ -133,3 +133,17 @@ TEST(Point2Test, AngleBetween)
 
   ASSERT_DOUBLE_EQ(keisan::Point2::angle_between(point_a, point_b), keisan::deg_to_rad(90.0));
 }
+
+TEST(Point2Test, DotProduct)
+{
+  auto point_a = keisan::Point2(4.0, 3.0);
+  auto point_b = keisan::Point2(3.0, 4.0);
+  ASSERT_DOUBLE_EQ(keisan::Point2::dot_product(point_a, point_b), 24.0);
+}
+
+TEST(Point2Test, CrossProduct)
+{
+  auto point_a = keisan::Point2(4.0, 3.0);
+  auto point_b = keisan::Point2(-3.0, 4.0);
+  ASSERT_DOUBLE_EQ(keisan::Point2::cross_product(point_a, point_b), 25.0);
+}

test/point_3_test.cpp

@@ -133,3 +133,17 @@ TEST(Point3Test, AngleBetween)
 
   ASSERT_DOUBLE_EQ(keisan::Point3::angle_between(point_a, point_b), keisan::deg_to_rad(90.0));
 }
+
+TEST(Point3Test, DotProduct)
+{
+  auto point_a = keisan::Point3(4.0, 3.0, 2.0);
+  auto point_b = keisan::Point3(3.0, 4.0, 5.0);
+  ASSERT_DOUBLE_EQ(keisan::Point3::dot_product(point_a, point_b), 34.0);
+}
+
+TEST(Point3Test, CrossProduct)
+{
+  auto point_a = keisan::Point3(3.0, 6.0, -3.0);
+  auto point_b = keisan::Point3(0.0, 2.0, 4.0);
+  ASSERT_DOUBLE_EQ(keisan::Point3::cross_product(point_a, point_b), sqrt(54.0) * sqrt(20.0));
+}