From ffd283b7d5cd1f3966518cc10bd25b0fce517a0d Mon Sep 17 00:00:00 2001
From: Alexander Mordvintsev <no@email>
Date: Wed, 11 Jul 2012 16:26:52 +0000
Subject: [PATCH] fixed SURF orientations, broken in r8892 (see also r8895,
 r8887 and #2043)

---
 modules/nonfree/src/surf.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/modules/nonfree/src/surf.cpp b/modules/nonfree/src/surf.cpp
index 1367cc6292..3ba4528c98 100644
--- a/modules/nonfree/src/surf.cpp
+++ b/modules/nonfree/src/surf.cpp
@@ -681,8 +681,8 @@ struct SURFInvoker
             if( !upright )
             {
                 descriptor_dir *= (float)(CV_PI/180);
-                float sin_dir = std::sin(descriptor_dir);
-                float cos_dir = std::cos(descriptor_dir);
+                float sin_dir = -std::sin(descriptor_dir);
+                float cos_dir =  std::cos(descriptor_dir);
 
                 /* Subpixel interpolation version (slower). Subpixel not required since
                 the pixels will all get averaged when we scale down to 20 pixels */