121 lines
3.9 KiB
C++
Executable File
121 lines
3.9 KiB
C++
Executable File
/**
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* @file llcriticaldamp.cpp
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* @brief Implementation of the critical damping functionality.
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*
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* $LicenseInfo:firstyear=2002&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2010, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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#include "linden_common.h"
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#include "llcriticaldamp.h"
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#include <algorithm>
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//-----------------------------------------------------------------------------
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// static members
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//-----------------------------------------------------------------------------
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LLFrameTimer LLSmoothInterpolation::sInternalTimer;
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std::vector<LLSmoothInterpolation::Interpolant> LLSmoothInterpolation::sInterpolants;
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F32 LLSmoothInterpolation::sTimeDelta;
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// helper functors
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struct LLSmoothInterpolation::CompareTimeConstants
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{
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bool operator()(const F32& a, const LLSmoothInterpolation::Interpolant& b) const
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{
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return a < b.mTimeScale;
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}
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bool operator()(const LLSmoothInterpolation::Interpolant& a, const F32& b) const
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{
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return a.mTimeScale < b; // bottom of a is higher than bottom of b
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}
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bool operator()(const LLSmoothInterpolation::Interpolant& a, const LLSmoothInterpolation::Interpolant& b) const
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{
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return a.mTimeScale < b.mTimeScale; // bottom of a is higher than bottom of b
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}
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};
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//-----------------------------------------------------------------------------
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// LLSmoothInterpolation()
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//-----------------------------------------------------------------------------
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LLSmoothInterpolation::LLSmoothInterpolation()
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{
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sTimeDelta = 0.f;
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}
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// static
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//-----------------------------------------------------------------------------
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// updateInterpolants()
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//-----------------------------------------------------------------------------
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void LLSmoothInterpolation::updateInterpolants()
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{
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sTimeDelta = sInternalTimer.getElapsedTimeAndResetF32();
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for (S32 i = 0; i < sInterpolants.size(); i++)
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{
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Interpolant& interp = sInterpolants[i];
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interp.mInterpolant = calcInterpolant(interp.mTimeScale);
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}
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}
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//-----------------------------------------------------------------------------
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// getInterpolant()
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//-----------------------------------------------------------------------------
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F32 LLSmoothInterpolation::getInterpolant(LLUnit<F32, LLUnits::Seconds> time_constant, bool use_cache)
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{
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if (time_constant == 0.f)
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{
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return 1.f;
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}
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if (use_cache)
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{
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interpolant_vec_t::iterator find_it = std::lower_bound(sInterpolants.begin(), sInterpolants.end(), time_constant.value(), CompareTimeConstants());
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if (find_it != sInterpolants.end() && find_it->mTimeScale == time_constant)
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{
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return find_it->mInterpolant;
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}
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else
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{
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Interpolant interp;
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interp.mTimeScale = time_constant.value();
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interp.mInterpolant = calcInterpolant(time_constant.value());
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sInterpolants.insert(find_it, interp);
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return interp.mInterpolant;
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}
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}
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else
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{
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return calcInterpolant(time_constant.value());
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}
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}
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//-----------------------------------------------------------------------------
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// calcInterpolant()
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//-----------------------------------------------------------------------------
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F32 LLSmoothInterpolation::calcInterpolant(F32 time_constant)
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{
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return llclamp(1.f - powf(2.f, -sTimeDelta / time_constant), 0.f, 1.f);
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}
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