diff options
Diffstat (limited to 'indra/llmath/llquaternion.h')
| -rw-r--r-- | indra/llmath/llquaternion.h | 70 |
1 files changed, 39 insertions, 31 deletions
diff --git a/indra/llmath/llquaternion.h b/indra/llmath/llquaternion.h index 5db9c5be2e..26da14ae20 100644 --- a/indra/llmath/llquaternion.h +++ b/indra/llmath/llquaternion.h @@ -2,31 +2,25 @@ * @file llquaternion.h * @brief LLQuaternion class header file. * - * $LicenseInfo:firstyear=2000&license=viewergpl$ - * - * Copyright (c) 2000-2009, Linden Research, Inc. - * + * $LicenseInfo:firstyear=2000&license=viewerlgpl$ * Second Life Viewer Source Code - * The source code in this file ("Source Code") is provided by Linden Lab - * to you under the terms of the GNU General Public License, version 2.0 - * ("GPL"), unless you have obtained a separate licensing agreement - * ("Other License"), formally executed by you and Linden Lab. Terms of - * the GPL can be found in doc/GPL-license.txt in this distribution, or - * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2 + * Copyright (C) 2010, Linden Research, Inc. * - * There are special exceptions to the terms and conditions of the GPL as - * it is applied to this Source Code. View the full text of the exception - * in the file doc/FLOSS-exception.txt in this software distribution, or - * online at - * http://secondlifegrid.net/programs/open_source/licensing/flossexception + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; + * version 2.1 of the License only. * - * By copying, modifying or distributing this software, you acknowledge - * that you have read and understood your obligations described above, - * and agree to abide by those obligations. + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. * - * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO - * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY, - * COMPLETENESS OR PERFORMANCE. + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA * $/LicenseInfo$ */ @@ -469,20 +463,30 @@ 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 +503,15 @@ 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 { |