diff options
| -rw-r--r-- | source/blender/bmesh/intern/bmesh_mesh.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/source/blender/bmesh/intern/bmesh_mesh.c b/source/blender/bmesh/intern/bmesh_mesh.c index f6c235271bf..c0cd2e31753 100644 --- a/source/blender/bmesh/intern/bmesh_mesh.c +++ b/source/blender/bmesh/intern/bmesh_mesh.c @@ -412,18 +412,24 @@ static void mesh_verts_calc_normals_accum_cb(void *userdata, MempoolIterData *mp * It also assumes that collisions between threads are highly unlikely, * else performances would be quite bad here. */ float virtual_lock = v_no[0]; - while ((virtual_lock = atomic_cas_float(&v_no[0], virtual_lock, FLT_MAX)) == FLT_MAX) { + for (virtual_lock = v_no[0]; + (virtual_lock == FLT_MAX) || (atomic_cas_float(&v_no[0], virtual_lock, FLT_MAX) != virtual_lock); + virtual_lock = v_no[0]) + { /* This loops until following conditions are met: * - v_no[0] has same value as virtual_lock (i.e. it did not change since last try). * - v_no_[0] was not FLT_MAX, i.e. it was not locked by another thread. */ } + BLI_assert(v_no[0] == FLT_MAX); /* Now we own that normal value, and can change it. * But first scalar of the vector must not be changed yet, it's our lock! */ virtual_lock += f_no[0] * fac; v_no[1] += f_no[1] * fac; v_no[2] += f_no[2] * fac; /* Second atomic operation to 'release' our lock on that vector and set its first scalar value. */ + /* Note that we do not need to loop here, since we 'locked' v_no[0], + * nobody should have changed it in the mean time. */ virtual_lock = atomic_cas_float(&v_no[0], FLT_MAX, virtual_lock); BLI_assert(virtual_lock == FLT_MAX); |