diff options
| author | Steve Bennetts <steve@lindenlab.com> | 2009-10-22 13:10:59 -0700 |
|---|---|---|
| committer | Steve Bennetts <steve@lindenlab.com> | 2009-10-22 13:10:59 -0700 |
| commit | b8ce05ed08a7db0825c04c217888814ef523027a (patch) | |
| tree | cae04332048f649e1280d3bdc3d20f46df773e67 /indra/llmath/llquaternion.h | |
| parent | e5484e56b3c13e65bd31d7bf21c1cd3a2d9333f2 (diff) | |
| parent | a464d469705aeae57fcdbfafa45e2bf592a182c5 (diff) | |
merge
Diffstat (limited to 'indra/llmath/llquaternion.h')
| -rw-r--r-- | indra/llmath/llquaternion.h | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/indra/llmath/llquaternion.h b/indra/llmath/llquaternion.h index 5db9c5be2e..0769f29f23 100644 --- a/indra/llmath/llquaternion.h +++ b/indra/llmath/llquaternion.h @@ -469,20 +469,30 @@ inline const LLQuaternion& operator*=(LLQuaternion &a, const LLQuaternion &b) return a; } +const F32 ONE_PART_IN_A_MILLION = 0.000001f; + inline F32 LLQuaternion::normalize() { F32 mag = sqrtf(mQ[VX]*mQ[VX] + mQ[VY]*mQ[VY] + mQ[VZ]*mQ[VZ] + mQ[VS]*mQ[VS]); if (mag > FP_MAG_THRESHOLD) { - F32 oomag = 1.f/mag; - mQ[VX] *= oomag; - mQ[VY] *= oomag; - mQ[VZ] *= oomag; - mQ[VS] *= oomag; + // Floating point error can prevent some quaternions from achieving + // exact unity length. When trying to renormalize such quaternions we + // can oscillate between multiple quantized states. To prevent such + // drifts we only renomalize if the length is far enough from unity. + if (fabs(1.f - mag) > ONE_PART_IN_A_MILLION) + { + F32 oomag = 1.f/mag; + mQ[VX] *= oomag; + mQ[VY] *= oomag; + mQ[VZ] *= oomag; + mQ[VS] *= oomag; + } } else { + // we were given a very bad quaternion so we set it to identity mQ[VX] = 0.f; mQ[VY] = 0.f; mQ[VZ] = 0.f; @@ -499,11 +509,15 @@ inline F32 LLQuaternion::normQuat() if (mag > FP_MAG_THRESHOLD) { - F32 oomag = 1.f/mag; - mQ[VX] *= oomag; - mQ[VY] *= oomag; - mQ[VZ] *= oomag; - mQ[VS] *= oomag; + if (fabs(1.f - mag) > ONE_PART_IN_A_MILLION) + { + // only renormalize if length not close enough to 1.0 already + F32 oomag = 1.f/mag; + mQ[VX] *= oomag; + mQ[VY] *= oomag; + mQ[VZ] *= oomag; + mQ[VS] *= oomag; + } } else { |