refactored random subsystem

added compile-time seed support

math/DrawList.h

@@ -2,8 +2,8 @@
 #define DRAWLIST_H
 
 #include <vector>
-#include <random>
 
+#include "Random.h"
 #include "../Assertions.h"
 
 /**
@@ -38,7 +38,7 @@ private:
 	std::vector<Entry> elements;
 
 	/** random number generator */
-	std::minstd_rand gen;
+	RandomGenerator gen;
 
 public:
 

math/Random.h

@@ -0,0 +1,28 @@
+#ifndef RANDOM_H
+#define RANDOM_H
+
+#include <cmath>
+#include <random>
+#include "../misc/Time.h"
+
+#ifdef USE_FIXED_SEED
+	#define RANDOM_SEED 1234
+#else
+	#define RANDOM_SEED ( std::chrono::system_clock::now().time_since_epoch() / std::chrono::milliseconds(1) )
+#endif
+
+//using RandomGenerator = std::minstd_rand;
+
+class RandomGenerator : public std::minstd_rand {
+
+public:
+
+	/** ctor with default seed */
+	RandomGenerator() : std::minstd_rand(RANDOM_SEED) {;}
+
+	/** ctor with custom seed */
+	RandomGenerator(result_type) : std::minstd_rand(RANDOM_SEED) {;}
+
+};
+
+#endif // RANDOM_H

math/distribution/Exponential.h

@@ -3,7 +3,7 @@
 
 #include <cmath>
 #include <random>
-
+#include "../Random.h"
 
 namespace Distribution {
 
@@ -14,13 +14,13 @@ namespace Distribution {
 
 		const T lambda;
 
-		std::minstd_rand gen;
+		RandomGenerator gen;
 		std::exponential_distribution<T> dist;
 
 	public:
 
 		/** ctor */
-		Exponential(const T lambda) : lambda(lambda), dist(lambda) {
+		Exponential(const T lambda) : lambda(lambda), gen(RANDOM_SEED), dist(lambda) {
 			;
 		}
 

math/distribution/Normal.h

@@ -3,6 +3,7 @@
 
 #include <cmath>
 #include <random>
+#include "../Random.h"
 
 namespace Distribution {
 
@@ -15,14 +16,14 @@ namespace Distribution {
 		const T sigma;
 		const T _a;
 
-		std::minstd_rand gen;
+		RandomGenerator gen;
 		std::normal_distribution<T> dist;
 
 	public:
 
 		/** ctor */
 		Normal(const T mu, const T sigma) :
-			mu(mu), sigma(sigma), _a(1.0 / (sigma * std::sqrt(2.0 * M_PI))), gen(1234), dist(mu,sigma) {
+			mu(mu), sigma(sigma), _a(1.0 / (sigma * std::sqrt(2.0 * M_PI))), gen(RANDOM_SEED), dist(mu,sigma) {
 
 		}
 

math/distribution/Uniform.h

@@ -3,6 +3,9 @@
 
 #include <cmath>
 #include <random>
+#include "../Random.h"
+
+#include <type_traits>
 
 namespace Distribution {
 
@@ -11,14 +14,17 @@ namespace Distribution {
 
 	private:
 
-		std::minstd_rand gen;
-		std::uniform_real_distribution<T> dist;
+		RandomGenerator gen;
+
+		/** depending on T, Dist is either a uniform_real or uniform_int distribution */
+		typedef typename std::conditional< std::is_floating_point<T>::value, std::uniform_real_distribution<T>, std::uniform_int_distribution<T> >::type Dist;
+		Dist dist;
+
 
 	public:
 
 		/** ctor */
-		Uniform(const T min, const T max) :
-			gen(1234), dist(min, max) {
+		Uniform(const T min, const T max) : gen(RANDOM_SEED), dist(min, max) {
 
 		}
 		/** get a uniformaly distributed random number */