diff options
| author | Chaosus <chaosus89@gmail.com> | 2019-03-17 20:51:51 +0300 |
|---|---|---|
| committer | Chaosus <chaosus89@gmail.com> | 2019-03-27 19:37:25 +0300 |
| commit | 6280be46a6fb62b8833a9d55bff590fb209b0fc6 (patch) | |
| tree | d87540826d691bf6f533b14efa27dbc14c8ced44 | |
| parent | df7d3708c5b535c3696943322a14ec19a175e30c (diff) | |
Properly setup seed in RNG
| -rw-r--r-- | core/math/random_pcg.cpp | 3 | ||||
| -rw-r--r-- | core/math/random_pcg.h | 6 | ||||
| -rw-r--r-- | thirdparty/misc/pcg.cpp | 10 | ||||
| -rw-r--r-- | thirdparty/misc/pcg.h | 1 |
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 |