From 4e2f56c78b5b79b1e206f5b8ee8767f3ce2c1226 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Mon, 27 Dec 2010 18:44:40 +0100
Subject: [PATCH] Function for negating a vector.

---
 src/Math/Test/VectorTest.cpp |  7 +++++++
 src/Math/Test/VectorTest.h   |  1 +
 src/Math/Vector.h            | 10 ++++++++++
 3 files changed, 18 insertions(+)

diff --git a/src/Math/Test/VectorTest.cpp b/src/Math/Test/VectorTest.cpp
index a60af9923..7d4f23d15 100644
--- a/src/Math/Test/VectorTest.cpp
+++ b/src/Math/Test/VectorTest.cpp
@@ -125,4 +125,11 @@ void VectorTest::angle() {
     QCOMPARE(Vector3::angle(a, b), 1.16251f);
 }
 
+void VectorTest::negative() {
+    float vec[] = { 1.0f, -3.0f, 5.0f, -10.0f };
+    float negative[] = { -1.0f, 3.0f, -5.0f, 10.0f };
+
+    QVERIFY(-Vector4(vec) == negative);
+}
+
 }}}
diff --git a/src/Math/Test/VectorTest.h b/src/Math/Test/VectorTest.h
index 83a2917d3..05dfe2e7b 100644
--- a/src/Math/Test/VectorTest.h
+++ b/src/Math/Test/VectorTest.h
@@ -33,6 +33,7 @@ class VectorTest: public QObject {
         void length();
         void normalized();
         void angle();
+        void negative();
 };
 
 }}}
diff --git a/src/Math/Vector.h b/src/Math/Vector.h
index e7ce856e1..e7c709b10 100644
--- a/src/Math/Vector.h
+++ b/src/Math/Vector.h
@@ -148,6 +148,16 @@ template<class T, size_t size> class Vector {
             return out;
         }
 
+        /** @brief Negative vector */
+        Vector<T, size> operator-() const {
+            Vector<T, size> out;
+
+            for(size_t i = 0; i != size; ++i)
+                out.set(i, -at(i));
+
+            return out;
+        }
+
         /** @brief Vector length */
         T length() const {
             T out(0);