fix build error on VS2012

diff --git a/modules/calib3d/src/ap3p.cpp b/modules/calib3d/src/ap3p.cpp
index ad2841f..db88a02 100644 (file)
--- a/modules/calib3d/src/ap3p.cpp
+++ b/modules/calib3d/src/ap3p.cpp
@@ -2,6 +2,9 @@
 
 #include <cmath>
 #include <complex>
+#if defined (_MSC_VER) && (_MSC_VER <= 1700)
+static inline double cbrt(double x) { return (double)cv::cubeRoot((float)x); };
+#endif
 
 using namespace std;