/** * @file llcriticaldamp.cpp * @brief Implementation of the critical damping functionality. * * $LicenseInfo:firstyear=2002&license=viewerlgpl$ * Second Life Viewer Source Code * Copyright (C) 2010, Linden Research, Inc. * * 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. * * 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. * * 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 * $/LicenseInfo$ */ #include "linden_common.h" #include "llcriticaldamp.h" //----------------------------------------------------------------------------- // static members //----------------------------------------------------------------------------- LLFrameTimer LLCriticalDamp::sInternalTimer; std::map<F32, F32> LLCriticalDamp::sInterpolants; F32 LLCriticalDamp::sTimeDelta; //----------------------------------------------------------------------------- // LLCriticalDamp() //----------------------------------------------------------------------------- LLCriticalDamp::LLCriticalDamp() { sTimeDelta = 0.f; } // static //----------------------------------------------------------------------------- // updateInterpolants() //----------------------------------------------------------------------------- void LLCriticalDamp::updateInterpolants() { sTimeDelta = sInternalTimer.getElapsedTimeAndResetF32(); F32 time_constant; for (std::map<F32, F32>::iterator iter = sInterpolants.begin(); iter != sInterpolants.end(); iter++) { time_constant = iter->first; F32 new_interpolant = 1.f - pow(2.f, -sTimeDelta / time_constant); new_interpolant = llclamp(new_interpolant, 0.f, 1.f); sInterpolants[time_constant] = new_interpolant; } } //----------------------------------------------------------------------------- // getInterpolant() //----------------------------------------------------------------------------- F32 LLCriticalDamp::getInterpolant(const F32 time_constant, BOOL use_cache) { if (time_constant == 0.f) { return 1.f; } if (use_cache && sInterpolants.count(time_constant)) { return sInterpolants[time_constant]; } F32 interpolant = 1.f - pow(2.f, -sTimeDelta / time_constant); interpolant = llclamp(interpolant, 0.f, 1.f); if (use_cache) { sInterpolants[time_constant] = interpolant; } return interpolant; }