From 48467814d4745cfe27835bd59cd1be6a98f29d58 Mon Sep 17 00:00:00 2001
From: Capostrophic <Capostrophic@users.noreply.github.com>
Date: Sun, 8 Apr 2018 23:10:14 +0300
Subject: [PATCH] Improve random number generation

---
 components/misc/rng.cpp | 15 +++++++++------
 components/misc/rng.hpp |  4 ++++
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/components/misc/rng.cpp b/components/misc/rng.cpp
index df0fc687e..dfe0eff40 100644
--- a/components/misc/rng.cpp
+++ b/components/misc/rng.cpp
@@ -1,28 +1,31 @@
 #include "rng.hpp"
-#include <cstdlib>
-#include <ctime>
+
+#include <chrono>
+#include <random>
 
 namespace Misc
 {
 
+    std::mt19937 Rng::generator = std::mt19937();
+
     void Rng::init()
     {
-        std::srand(static_cast<unsigned int>(std::time(NULL)));
+        generator.seed(static_cast<unsigned int>(std::chrono::high_resolution_clock::now().time_since_epoch().count()));
     }
 
     float Rng::rollProbability()
     {
-        return static_cast<float>(std::rand() / (static_cast<double>(RAND_MAX)+1.0));
+        return std::uniform_real_distribution<float>(0, 1 - std::numeric_limits<float>::epsilon())(generator);
     }
 
     float Rng::rollClosedProbability()
     {
-        return static_cast<float>(std::rand() / static_cast<double>(RAND_MAX));
+        return std::uniform_real_distribution<float>(0, 1)(generator);
     }
 
     int Rng::rollDice(int max)
     {
-        return static_cast<int>((std::rand() / (static_cast<double>(RAND_MAX)+1.0)) * (max));
+        return std::uniform_int_distribution<int>(0, max - 1)(generator);
     }
 
 }
diff --git a/components/misc/rng.hpp b/components/misc/rng.hpp
index 01fcdd763..ff56906d9 100644
--- a/components/misc/rng.hpp
+++ b/components/misc/rng.hpp
@@ -2,6 +2,7 @@
 #define OPENMW_COMPONENTS_MISC_RNG_H
 
 #include <cassert>
+#include <random>
 
 namespace Misc
 {
@@ -13,6 +14,9 @@ class Rng
 {
 public:
 
+    /// create a RNG
+    static std::mt19937 generator;
+
     /// seed the RNG
     static void init();