Fix a compilation error when using clang++

Clang gives this error:

  In file included from opencv_trail_effect.cpp:25:
  ./Trail.hpp:13:22: error: in-class initialization of non-static data member is a C++11 extension [-Werror,-Wc++11-extensions]
          cv::Mat *background = NULL;
                              ^
  1 error generated.
  <builtin>: recipe for target 'opencv_trail_effect.o' failed
  make: *** [opencv_trail_effect.o] Error 1

Fix it to make compilation succeed.

diff --git a/Trail.hpp b/Trail.hpp
index e519c94..ecf486a 100644 (file)
--- a/Trail.hpp
+++ b/Trail.hpp
@@ -10,7 +10,7 @@ class Trail {
 private:
        virtual void iterate(cv::Mat& frame, void (*action)(cv::Mat&, Frame *, int, int)) = 0;
 
-       cv::Mat *background = NULL;
+       cv::Mat *background;
        bool redraw_current_frame;
        bool persistent;
 
@@ -58,6 +58,7 @@ protected:
 public:
        Trail(int trail_length, cv::Size frame_size)
        {
+               background = NULL;
                redraw_current_frame = false;
                drawStrategy = frameCopy;
                persistent = false;