Add random generator that accepts state for repetability

src/values/MyRand.cpp

@@ -1,25 +0,0 @@
-#include <inttypes.h>
-
-static uint32_t rprand_state[4] = {0};
-
-static inline uint32_t my_rotate_left(const uint32_t x, int k)
-{
-  return (x << k) | (x >> (32 - k));
-}
-
-uint32_t my_rprand_xoshiro(void)
-{
-  const uint32_t result = my_rotate_left(rprand_state[1] * 5, 7) * 9;
-  const uint32_t t = rprand_state[1] << 9;
-
-  rprand_state[2] ^= rprand_state[0];
-  rprand_state[3] ^= rprand_state[1];
-  rprand_state[1] ^= rprand_state[2];
-  rprand_state[0] ^= rprand_state[3];
-
-  rprand_state[2] ^= t;
-
-  rprand_state[3] = my_rotate_left(rprand_state[3], 11);
-
-  return result;
-}

src/values/RandBuffer.cpp

@@ -1,5 +1,5 @@
 #include "values/RandBuffer.hpp"
-#include "Math.hpp"
+#include "values/mrand.hpp"
 
 void RandBuffer::reset()
 {
@@ -13,7 +13,7 @@ float RandBuffer::next()
   {
     return ((float *)m_buffer.buffer)[m_pos++];
   }
-  float ret = GetRandomFloat();
+  float ret = mrand::getFloat();
   m_buffer.add_end((uint8_t *)&ret, sizeof(float));
   m_pos++;
   return ret;

src/values/mrand.cpp

@@ -0,0 +1,63 @@
+#include <inttypes.h>
+#include <algorithm>
+#include "values/mrand.hpp"
+
+static uint32_t rprand_state[4] = {0};
+static uint64_t rprand_seed = 0;
+
+static inline uint32_t my_rotate_left(const uint32_t x, int k)
+{
+  return (x << k) | (x >> (32 - k));
+}
+
+uint32_t my_rprand_xoshiro(uint32_t state[4])
+{
+  const uint32_t result = my_rotate_left(state[1] * 5, 7) * 9;
+  const uint32_t t = state[1] << 9;
+
+  state[2] ^= state[0];
+  state[3] ^= state[1];
+  state[1] ^= state[2];
+  state[0] ^= state[3];
+
+  state[2] ^= t;
+
+  state[3] = my_rotate_left(state[3], 11);
+
+  return result;
+}
+
+uint64_t rprand_splitmix64()
+{
+  uint64_t z = (rprand_seed += 0x9e3779b97f4a7c15);
+  z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
+  z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
+  return z ^ (z >> 31);
+}
+
+namespace mrand
+{
+  void setSeed(unsigned long long seed)
+  {
+    rprand_seed = (uint64_t)seed; // Set SplitMix64 seed for further use
+
+    // To generate the Xoshiro128** state, we use SplitMix64 generator first
+    // We generate 4 pseudo-random 64bit numbers that we combine using their LSB|MSB
+    rprand_state[0] = (uint32_t)(rprand_splitmix64() & 0xffffffff);
+    rprand_state[1] = (uint32_t)((rprand_splitmix64() & 0xffffffff00000000) >> 32);
+    rprand_state[2] = (uint32_t)(rprand_splitmix64() & 0xffffffff);
+    rprand_state[3] = (uint32_t)((rprand_splitmix64() & 0xffffffff00000000) >> 32);
+  }
+
+  int getValue(int min, int max)
+  {
+    int value = my_rprand_xoshiro(rprand_state) % (std::abs(max - min) + 1) + min;
+
+    return value;
+  }
+
+  float getFloat()
+  {
+    return my_rprand_xoshiro(rprand_state) / 4294967295.0f;
+  }
+}