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authorRĂ©mi Verschelde <rverschelde@gmail.com>2019-04-01 17:17:30 +0200
committerGitHub <noreply@github.com>2019-04-01 17:17:30 +0200
commit29a1202d39b0efb617a8ff4ee9764612f3e0124f (patch)
treeae139220628ef18ce35a14d47a5aaefab3cceae1
parent18ee888541de80307da68808f3996ae2b0a807ab (diff)
parent6280be46a6fb62b8833a9d55bff590fb209b0fc6 (diff)
Merge pull request #27171 from Chaosus/randfix
Properly setup seed in RNG
-rw-r--r--core/math/random_pcg.cpp3
-rw-r--r--core/math/random_pcg.h6
-rw-r--r--thirdparty/misc/pcg.cpp10
-rw-r--r--thirdparty/misc/pcg.h1
4 files changed, 15 insertions, 5 deletions
diff --git a/core/math/random_pcg.cpp b/core/math/random_pcg.cpp
index 45467b32b2..8351bd138e 100644
--- a/core/math/random_pcg.cpp
+++ b/core/math/random_pcg.cpp
@@ -34,8 +34,7 @@
RandomPCG::RandomPCG(uint64_t p_seed, uint64_t p_inc) :
pcg(),
- current_seed(DEFAULT_SEED) {
- pcg.inc = p_inc;
+ current_inc(p_inc) {
seed(p_seed);
}
diff --git a/core/math/random_pcg.h b/core/math/random_pcg.h
index 230eb9a11b..cd721ef4d1 100644
--- a/core/math/random_pcg.h
+++ b/core/math/random_pcg.h
@@ -38,18 +38,18 @@
class RandomPCG {
pcg32_random_t pcg;
uint64_t current_seed; // seed with this to get the same state
+ uint64_t current_inc;
public:
static const uint64_t DEFAULT_SEED = 12047754176567800795U;
static const uint64_t DEFAULT_INC = PCG_DEFAULT_INC_64;
static const uint64_t RANDOM_MAX = 0xFFFFFFFF;
- RandomPCG(uint64_t p_seed = DEFAULT_SEED, uint64_t p_inc = PCG_DEFAULT_INC_64);
+ RandomPCG(uint64_t p_seed = DEFAULT_SEED, uint64_t p_inc = DEFAULT_INC);
_FORCE_INLINE_ void seed(uint64_t p_seed) {
current_seed = p_seed;
- pcg.state = p_seed;
- pcg32_random_r(&pcg); // Force changing internal state to avoid initial 0
+ pcg32_srandom_r(&pcg, current_seed, current_inc);
}
_FORCE_INLINE_ uint64_t get_seed() { return current_seed; }
diff --git a/thirdparty/misc/pcg.cpp b/thirdparty/misc/pcg.cpp
index eac3b36d36..c421e16f89 100644
--- a/thirdparty/misc/pcg.cpp
+++ b/thirdparty/misc/pcg.cpp
@@ -13,3 +13,13 @@ uint32_t pcg32_random_r(pcg32_random_t* rng)
uint32_t rot = oldstate >> 59u;
return (xorshifted >> rot) | (xorshifted << ((-rot) & 31));
}
+
+// Source from http://www.pcg-random.org/downloads/pcg-c-basic-0.9.zip
+void pcg32_srandom_r(pcg32_random_t* rng, uint64_t initstate, uint64_t initseq)
+{
+ rng->state = 0U;
+ rng->inc = (initseq << 1u) | 1u;
+ pcg32_random_r(rng);
+ rng->state += initstate;
+ pcg32_random_r(rng);
+}
diff --git a/thirdparty/misc/pcg.h b/thirdparty/misc/pcg.h
index e2d66d51d5..6f42b3b094 100644
--- a/thirdparty/misc/pcg.h
+++ b/thirdparty/misc/pcg.h
@@ -10,5 +10,6 @@
typedef struct { uint64_t state; uint64_t inc; } pcg32_random_t;
uint32_t pcg32_random_r(pcg32_random_t* rng);
+void pcg32_srandom_r(pcg32_random_t* rng, uint64_t initstate, uint64_t initseq);
#endif // RANDOM_H