From 97e80f5df3610b2c09dd199c64e943e5602509e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Thu, 23 Dec 2010 23:13:46 +0100
Subject: [PATCH] Function for multiplying vector with matrix.

---
 src/Matrix.h            | 13 +++++++++++++
 src/Test/MatrixTest.cpp | 18 ++++++++++++++++++
 src/Test/MatrixTest.h   |  1 +
 3 files changed, 32 insertions(+)

diff --git a/src/Matrix.h b/src/Matrix.h
index 1d2380100..45bda5aed 100644
--- a/src/Matrix.h
+++ b/src/Matrix.h
@@ -21,6 +21,7 @@
 
 #include <cstring>
 
+#include "Vector.h"
 #include "constants.h"
 
 namespace Magnum {
@@ -114,6 +115,18 @@ template<class T, size_t size> class Matrix {
             return out;
         }
 
+        /** @brief Multiply vector operator */
+        Vector<T, size> operator*(const Vector<T, size>& other) const {
+            Vector<T, size> out;
+
+            for(size_t row = 0; row != size; ++row) {
+                for(size_t pos = 0; pos != size; ++pos)
+                    out.add(row, at(pos, row)*other.at(pos));
+            }
+
+            return out;
+        }
+
         /** @brief Transposed matrix */
         Matrix<T, size> transposed() const {
             Matrix<T, size> out;
diff --git a/src/Test/MatrixTest.cpp b/src/Test/MatrixTest.cpp
index aefcdab59..786668bd5 100644
--- a/src/Test/MatrixTest.cpp
+++ b/src/Test/MatrixTest.cpp
@@ -135,6 +135,24 @@ void MatrixTest::multiply() {
     QVERIFY(is);
 }
 
+void MatrixTest::multiplyVector() {
+    int matrix[] = {
+         -3,  -3,  -1,   3,  -5,
+         -1,  -3,  -5,   2,   3,
+         -1,  -4,   3,  -1,  -2,
+         -5,  -5,  -1,  -4,  -1,
+          1,   3,  -3,  -4,  -1
+    };
+
+    int vector[] = { 0, 5, 3, 4, 4 };
+
+    int expected[] = { -24, -35, -32, -25, 1 };
+
+    bool is = (Matrix<int, 5>(matrix)*Vector<int, 5>(vector) == Vector<int, 5>(expected));
+
+    QVERIFY(is);
+}
+
 void MatrixTest::transposed() {
     float original[] = {
         0.0f,   1.0f,   2.0f,   3.0f,
diff --git a/src/Test/MatrixTest.h b/src/Test/MatrixTest.h
index 71058d001..39dfb99d4 100644
--- a/src/Test/MatrixTest.h
+++ b/src/Test/MatrixTest.h
@@ -29,6 +29,7 @@ class MatrixTest: public QObject {
         void copy();
         void multiplyIdentity();
         void multiply();
+        void multiplyVector();
         void transposed();
 };