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| author | Christian Goetze <cg@lindenlab.com> | 2009-07-01 00:22:05 +0000 |
|---|---|---|
| committer | Christian Goetze <cg@lindenlab.com> | 2009-07-01 00:22:05 +0000 |
| commit | e588d1f28419745ee1e1ee98dc1852e0364a4088 (patch) | |
| tree | 8a3546576e0d5a8f0cf32cca68d0913f1061d523 /indra/llmath/llquaternion.h | |
| parent | 5f4c09fa1f4b09126e1a16e78044c64e97828530 (diff) | |
svn merge -r125825:125901 svn+ssh://svn.lindenlab.com/svn/user/cg/qar-1654
QAR-1654 merge completed.
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 { |