Changeset 10813

Timestamp:

Nov 17, 2015, 6:28:25 PM (8 years ago)

Author:

muemart

Message:

Use new random number generation functions

Location:

code/branches/cpp11_v2/src/libraries

Files:

• core/CoreConfig.cc (modified) (2 diffs)
• util/Math.cc (modified) (1 diff)
• util/Math.h (modified) (5 diffs)

code/branches/cpp11_v2/src/libraries/core/CoreConfig.cc

@@ -35 +35 @@
 #include "core/Language.h"
 #include "core/ApplicationPaths.h"
+
+#include <random>
 
 namespace orxonox
@@ -129 +131 @@
         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;

code/branches/cpp11_v2/src/libraries/util/Math.cc

@@ -371 +371 @@
     }
 
+
+    namespace detail
+    {
+        std::mt19937 rngen;
+    }
+
     /**
         @brief Returns a unique number. This function will never return the same value twice.

code/branches/cpp11_v2/src/libraries/util/Math.h

@@ -46 +46 @@
 #include <cmath>
 #include <cstdlib>
+#include <random>
 
 #include <OgreMath.h>
@@ -252 +253 @@
     }
 
+    namespace detail
+    {
+        /**
+        Random number generator used for the functions below. Marked extern to only have one global instance.
+        */
+        _UtilExport extern std::mt19937 rngen;
+    }
+
+    /**
+    @brief Seeds the random number generator used for the functions below.
+    */
+    inline void rndseed(unsigned int seed)
+    {
+        detail::rngen.seed(seed);
+    }
+
+    /**
+    @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 min, float max)
+    {
+        std::uniform_real_distribution<float> dist(min, max);
+        return dist(detail::rngen);
+    }
+
     /**
         @brief Returns a random number between 0 and almost 1: <tt>0 <= rnd < 1</tt>.
@@ -257 +285 @@
     inline float rnd()
     {
-        return rand() / (RAND_MAX + 1.0f);
+        return rnd(0, 1);
     }
 
@@ -266 +294 @@
     inline float rnd(float max)
     {
-        return rnd() * max;
-    }
-
-    /**
-        @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 min, float max)
-    {
-        return rnd(max - min) + min;
+        return rnd(0, max);
     }
 
@@ -284 +302 @@
     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
     }