/** * @file llcriticaldamp.h * @brief A lightweight class that calculates critical damping constants once * per frame. * * $LicenseInfo:firstyear=2002&license=viewerlgpl$ * 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 * $/LicenseInfo$ */ #ifndef LL_LLCRITICALDAMP_H #define LL_LLCRITICALDAMP_H #include <vector> #include "llframetimer.h" #include "llunits.h" class LL_COMMON_API LLSmoothInterpolation { public: LLSmoothInterpolation(); // MANIPULATORS static void updateInterpolants(); // ACCESSORS static F32 getInterpolant(F32SecondsImplicit time_constant, bool use_cache = true); template<typename T> static T lerp(T a, T b, F32SecondsImplicit time_constant, bool use_cache = true) { F32 interpolant = getInterpolant(time_constant, use_cache); return ((a * (1.f - interpolant)) + (b * interpolant)); } protected: static F32 calcInterpolant(F32 time_constant); struct CompareTimeConstants; static LLFrameTimer sInternalTimer; // frame timer for calculating deltas struct Interpolant { F32 mTimeScale; F32 mInterpolant; }; typedef std::vector<Interpolant> interpolant_vec_t; static interpolant_vec_t sInterpolants; static F32 sTimeDelta; }; typedef LLSmoothInterpolation LLCriticalDamp; #endif // LL_LLCRITICALDAMP_H