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| author | Vir Linden <60274682+vir-linden@users.noreply.github.com> | 2024-04-24 16:02:42 -0400 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-04-24 16:02:42 -0400 |
| commit | a3602d660c89a10126946d9c789e454fbfbc34bd (patch) | |
| tree | 1cd70015b45a432f599036f181dd93c53c59393a /indra/llcommon/llrand.cpp | |
| parent | 6ca4dfdb56d0107368a09af2b089c24d32e7108d (diff) | |
| parent | d98fc504a1d4bc292ba86acdda053c8b4598a193 (diff) | |
Merge pull request #1323 from secondlife/main
Update from main
Diffstat (limited to 'indra/llcommon/llrand.cpp')
| -rw-r--r-- | indra/llcommon/llrand.cpp | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/indra/llcommon/llrand.cpp b/indra/llcommon/llrand.cpp index 33afc50cf7..0192111574 100644 --- a/indra/llcommon/llrand.cpp +++ b/indra/llcommon/llrand.cpp @@ -58,7 +58,9 @@ * to restore uniform distribution. */ -static LLRandLagFib2281 gRandomGenerator(LLUUID::getRandomSeed()); +// gRandomGenerator is a stateful static object, which is therefore not +// inherently thread-safe. +static thread_local LLRandLagFib2281 gRandomGenerator(LLUUID::getRandomSeed()); // no default implementation, only specific F64 and F32 specializations template <typename REAL> @@ -71,7 +73,7 @@ inline F64 ll_internal_random<F64>() // CPUs (or at least multi-threaded processes) seem to // occasionally give an obviously incorrect random number -- like // 5^15 or something. Sooooo, clamp it as described above. - F64 rv = gRandomGenerator(); + F64 rv{ gRandomGenerator() }; if(!((rv >= 0.0) && (rv < 1.0))) return fmod(rv, 1.0); return rv; } @@ -79,7 +81,13 @@ inline F64 ll_internal_random<F64>() template <> inline F32 ll_internal_random<F32>() { - return F32(ll_internal_random<F64>()); + // *HACK: clamp the result as described above. + // Per Monty, it's important to clamp using the correct fmodf() rather + // than expanding to F64 for fmod() and then truncating back to F32. Prior + // to this change, we were getting sporadic ll_frand() == 1.0 results. + F32 rv{ narrow<F32>(gRandomGenerator()) }; + if(!((rv >= 0.0f) && (rv < 1.0f))) return fmodf(rv, 1.0f); + return rv; } /*------------------------------ F64 aliases -------------------------------*/ |