[Orxonox-commit 6155] r10813 - in code/branches/cpp11_v2/src/libraries: core util

[muemart at orxonox.net]

Author: muemart
Date: 2015-11-17 18:28:25 +0100 (Tue, 17 Nov 2015)
New Revision: 10813

Modified:
   code/branches/cpp11_v2/src/libraries/core/CoreConfig.cc
   code/branches/cpp11_v2/src/libraries/util/Math.cc
   code/branches/cpp11_v2/src/libraries/util/Math.h
Log:
Use new random number generation functions

Modified: code/branches/cpp11_v2/src/libraries/core/CoreConfig.cc
===================================================================
--- code/branches/cpp11_v2/src/libraries/core/CoreConfig.cc	2015-11-16 15:30:49 UTC (rev 10812)
+++ code/branches/cpp11_v2/src/libraries/core/CoreConfig.cc	2015-11-17 17:28:25 UTC (rev 10813)
@@ -35,6 +35,8 @@
 #include "core/Language.h"
 #include "core/ApplicationPaths.h"
 
+#include <random>
+
 namespace orxonox
 {
     RegisterClassNoArgs(CoreConfig);
@@ -128,7 +130,10 @@
         static bool bInitialized = false;
         if (!bInitialized && this->bInitRandomNumberGenerator_)
         {
-            srand(static_cast<unsigned int>(time(0)));
+            std::random_device rnddev;
+            rndseed(rnddev());
+            //Keep the old seeding around because people will probably still use the old functions
+            srand(rnddev());
             rand();
             bInitialized = true;
         }

Modified: code/branches/cpp11_v2/src/libraries/util/Math.cc
===================================================================
--- code/branches/cpp11_v2/src/libraries/util/Math.cc	2015-11-16 15:30:49 UTC (rev 10812)
+++ code/branches/cpp11_v2/src/libraries/util/Math.cc	2015-11-17 17:28:25 UTC (rev 10813)
@@ -370,6 +370,12 @@
         return (targetposition + targetvelocity * time);
     }
 
+
+    namespace detail
+    {
+        std::mt19937 rngen;
+    }
+
     /**
         @brief Returns a unique number. This function will never return the same value twice.
     */

Modified: code/branches/cpp11_v2/src/libraries/util/Math.h
===================================================================
--- code/branches/cpp11_v2/src/libraries/util/Math.h	2015-11-16 15:30:49 UTC (rev 10812)
+++ code/branches/cpp11_v2/src/libraries/util/Math.h	2015-11-17 17:28:25 UTC (rev 10813)
@@ -45,6 +45,7 @@
 #include <string>
 #include <cmath>
 #include <cstdlib>
+#include <random>
 
 #include <OgreMath.h>
 #include <OgreVector2.h>
@@ -251,31 +252,48 @@
         return static_cast<T>((-2 * (end - start) * cube(time)) + (3 * (end - start) * square(time)) + start);
     }
 
+    namespace detail
+    {
+        /**
+        Random number generator used for the functions below. Marked extern to only have one global instance.
+        */
+        _UtilExport extern std::mt19937 rngen;
+    }
+
     /**
-        @brief Returns a random number between 0 and almost 1: <tt>0 <= rnd < 1</tt>.
+    @brief Seeds the random number generator used for the functions below.
     */
-    inline float rnd()
+    inline void rndseed(unsigned int seed)
     {
-        return rand() / (RAND_MAX + 1.0f);
+        detail::rngen.seed(seed);
     }
 
     /**
-        @brief Returns a random number between 0 and almost @a max: <tt>0 <= rnd < max</tt>.
-        @param max The maximum
+    @brief Returns a random number between @a min and almost @a max: <tt>min <= rnd < max</tt>.
+    @param min The minimum
+    @param max The maximum
     */
-    inline float rnd(float max)
+    inline float rnd(float min, float max)
     {
-        return rnd() * max;
+        std::uniform_real_distribution<float> dist(min, max);
+        return dist(detail::rngen);
     }
 
     /**
-        @brief Returns a random number between @a min and almost @a max: <tt>min <= rnd < max</tt>.
-        @param min The minimum
+        @brief Returns a random number between 0 and almost 1: <tt>0 <= rnd < 1</tt>.
+    */
+    inline float rnd()
+    {
+        return rnd(0, 1);
+    }
+
+    /**
+        @brief Returns a random number between 0 and almost @a max: <tt>0 <= rnd < max</tt>.
         @param max The maximum
     */
-    inline float rnd(float min, float max)
+    inline float rnd(float max)
     {
-        return rnd(max - min) + min;
+        return rnd(0, max);
     }
 
     /**
@@ -283,7 +301,8 @@
     */
     inline float rndsgn()
     {
-        return static_cast<float>((rand() & 0x2) - 1); // rand() & 0x2 is either 2 or 0
+        std::uniform_int_distribution<> dist;
+        return static_cast<float>((dist(detail::rngen) & 0x2) - 1); // dist(...) & 0x2 is either 2 or 0
     }
 
     _UtilExport unsigned long getUniqueNumber();