/** * @file llcriticaldamp.cpp * @brief Implementation of the critical damping functionality. * * $LicenseInfo:firstyear=2002&license=viewergpl$ * * Copyright (c) 2002-2009, Linden Research, Inc. * * 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 * * 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 * * 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. * * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY, * COMPLETENESS OR PERFORMANCE. * $/LicenseInfo$ */ #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; }