X-Git-Url: http://shamusworld.gotdns.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fvector.cpp;h=e992bbffd53aa5496bffde85c0ff6b543f4891fd;hb=8ab4e08bd78cb5b07f069e3e6c5bf76944cb14fa;hp=da0d4c557aae2fe4e68b5df17d8cf0d4ce5f0ccf;hpb=9f6ad3fe0b9cb30115a5d38e8af3aebed0d70c08;p=architektonas

diff --git a/src/vector.cpp b/src/vector.cpp
index da0d4c5..e992bbf 100644
--- a/src/vector.cpp
+++ b/src/vector.cpp
@@ -1,7 +1,7 @@
 //
 // vector.cpp: Various structures used for 3 dimensional imaging
 //
-// by James L. Hammons
+// by James Hammons
 // (C) 2006 Underground Software
 //
 // JLH = James L. Hammons <jlhamm@acm.org>
@@ -25,6 +25,10 @@ Vector::Vector(double xx/*= 0*/, double yy/*= 0*/, double zz/*= 0*/): x(xx), y(y
 {
 }
 
+Vector::Vector(Vector head, Vector tail): x(head.x - tail.x), y(head.y - tail.y), z(head.z - tail.z)
+{
+}
+
 Vector Vector::operator=(Vector const v)
 {
 	x = v.x, y = v.y, z = v.z;
@@ -129,6 +133,35 @@ Vector& Vector::operator+=(double const v)
 	return *this;
 }
 
+// Vector - vector, self assigned
+
+Vector& Vector::operator-=(Vector const v)
+{
+	x -= v.x, y -= v.y, z -= v.z;
+
+	return *this;
+}
+
+// Vector - constant, self assigned
+
+Vector& Vector::operator-=(double const v)
+{
+	x -= v, y -= v, z -= v;
+
+	return *this;
+}
+
+// Check for equality
+bool Vector::operator==(Vector const v)
+{
+	return (x == v.x && y == v.y && z == v.z ? true : false);
+}
+
+// Check for inequality
+bool Vector::operator!=(Vector const v)
+{
+	return (x != v.x || y != v.y || z != v.z ? true : false);
+}
 
 Vector Vector::Unit(void)
 {
@@ -169,3 +202,11 @@ double Vector::Dot(Vector v1, Vector v2)
 {
 	return (v1.x * v2.x) + (v1.y * v2.y) + (v1.z * v2.z);
 }
+
+double Vector::Magnitude(Vector v1, Vector v2)
+{
+	double xx = v1.x - v2.x;
+	double yy = v1.y - v2.y;
+	double zz = v1.z - v2.z;
+	return sqrt(xx * xx + yy * yy + zz * zz);
+}