Use xoroshiro128+ random generator (everywhere besides BSON code).

src/Probability.cpp

@@ -16,6 +16,7 @@
 #include <numeric>
 #include <cstdlib>
 #include "Probability.h"
+#include "common/tpt-rand.h"
 
 namespace Probability
 {
@@ -25,11 +26,6 @@ float binomial_gte1(int n, float p)
 	return 1.0f - std::pow(1.0f-p, n);
 }
 
-float randFloat()
-{
-	return static_cast<float>(rand())/RAND_MAX;
-}
-
 SmallKBinomialGenerator::SmallKBinomialGenerator(unsigned int n, float p, unsigned int maxK_)
 {
 	maxK = maxK_;

src/Probability.h

@@ -25,7 +25,6 @@ namespace Probability
 	// X ~ binomial(n,p), returns P(X>=1)
 	// e.g. If a reaction has n chances of occurring, each time with probability p, this returns the probability that it occurs at least once.
 	float binomial_gte1(int n, float p);
-	float randFloat();
 
 	class SmallKBinomialGenerator
 	{

src/common/tpt-rand.cpp

@@ -0,0 +1,51 @@
+#include "tpt-rand.h"
+#include <cstdlib>
+
+/* xoroshiro128+ by David Blackman and Sebastiano Vigna */
+
+static inline uint64_t rotl(const uint64_t x, int k) {
+	return (x << k) | (x >> (64 - k));
+}
+
+uint64_t RandomGen::next(void) {
+	const uint64_t s0 = s[0];
+	uint64_t s1 = s[1];
+	const uint64_t result = s0 + s1;
+
+	s1 ^= s0;
+	s[0] = rotl(s0, 55) ^ s1 ^ (s1 << 14); // a, b
+	s[1] = rotl(s1, 36); // c
+
+	return result;
+}
+
+unsigned int RandomGen::operator()()
+{
+	return next()&0xFFFFFFFF;
+}
+
+unsigned int RandomGen::between(unsigned int lower, unsigned int upper)
+{
+	unsigned int r = (*this)();
+
+	return r % (upper - lower + 1) + lower;
+}
+
+float RandomGen::uniform01()
+{
+	return static_cast<float>(random_gen())/(float)0xFFFFFFFF;
+}
+
+RandomGen::RandomGen()
+{
+	s[0] = 1;
+	s[1] = 2;
+}
+
+void RandomGen::seed(unsigned int sd)
+{
+	s[0] = sd;
+	s[1] = sd;
+}
+
+RandomGen random_gen;

src/common/tpt-rand.h

@@ -0,0 +1,22 @@
+#ifndef TPT_RAND_
+#define TPT_RAND_
+
+#include <stdint.h>
+
+class RandomGen
+{
+private:
+	uint64_t s[2];
+	uint64_t next(void);
+public:
+	unsigned int operator()();
+	unsigned int between(unsigned int lower, unsigned int upper);
+	float uniform01();
+
+	RandomGen();
+	void seed(unsigned int sd);
+};
+
+extern RandomGen random_gen;
+
+#endif /* TPT_RAND_ */

src/graphics/Renderer.cpp

@@ -8,6 +8,7 @@
 #include "Renderer.h"
 #include "Graphics.h"
 #include "common/tpt-math.h"
+#include "common/tpt-rand.h"
 #include "common/tpt-minmax.h"
 #include "gui/game/RenderPreset.h"
 #include "simulation/Elements.h"
@@ -1774,7 +1775,7 @@ void Renderer::render_parts()
 				}
 				if(pixel_mode & PMODE_SPARK)
 				{
-					flicker = rand()%20;
+					flicker = random_gen()%20;
 #ifdef OGLR
 					//Oh god, this is awful
 					lineC[clineC++] = ((float)colr)/255.0f;
@@ -1838,7 +1839,7 @@ void Renderer::render_parts()
 				}
 				if(pixel_mode & PMODE_FLARE)
 				{
-					flicker = rand()%20;
+					flicker = random_gen()%20;
 #ifdef OGLR
 					//Oh god, this is awful
 					lineC[clineC++] = ((float)colr)/255.0f;
@@ -1911,7 +1912,7 @@ void Renderer::render_parts()
 				}
 				if(pixel_mode & PMODE_LFLARE)
 				{
-					flicker = rand()%20;
+					flicker = random_gen()%20;
 #ifdef OGLR
 					//Oh god, this is awful
 					lineC[clineC++] = ((float)colr)/255.0f;

src/gui/preview/PreviewView.cpp

@@ -17,6 +17,8 @@
 #include "gui/interface/AvatarButton.h"
 #include "gui/interface/Keys.h"
 #include "gui/dialogues/ErrorMessage.h"
+#include "common/tpt-math.h"
+#include "common/tpt-rand.h"
 
 class PreviewView::LoginAction: public ui::ButtonAction
 {
@@ -297,7 +299,7 @@ void PreviewView::CheckComment()
 	{
 		if (!commentHelpText)
 		{
-			if (rand()%2)
+			if (random_gen()%2)
 				commentWarningLabel->SetText("Stolen? Report the save instead");
 			else
 				commentWarningLabel->SetText("Please report stolen saves");
@@ -313,7 +315,7 @@ void PreviewView::CheckComment()
 	{
 		if (!commentHelpText)
 		{
-			if (rand()%2)
+			if (random_gen()%2)
 				commentWarningLabel->SetText("Please do not swear");
 			else
 				commentWarningLabel->SetText("Bad language may be deleted");

src/simulation/Air.cpp

@@ -6,6 +6,7 @@
 //#include <powder.h>
 //#include <defines.h>
 #include "Gravity.h"
+#include "common/tpt-rand.h"
 
 /*float kernel[9];
 
@@ -373,7 +374,7 @@ void Air::RecalculateBlockAirMaps()
 			}
 		}
 		// mostly accurate insulator blocking, besides checking GEL
-		else if ((type == PT_HSWC && sim.parts[i].life != 10) || sim.elements[type].HeatConduct <= (rand()%250))
+		else if ((type == PT_HSWC && sim.parts[i].life != 10) || sim.elements[type].HeatConduct <= (random_gen()%250))
 		{
 			int x = ((int)(sim.parts[i].x+0.5f))/CELL, y = ((int)(sim.parts[i].y+0.5f))/CELL;
 			if (sim.InBounds(x, y) && !(bmap_blockairh[y][x]&0x8))

src/simulation/Elements.h

@@ -70,6 +70,7 @@
 struct playerst;
 
 #include "ElementClasses.h"
+#include "common/tpt-rand.h"
 
 
 #endif /* ELEMENTS_H_ */