73 lines
2.0 KiB
C++
73 lines
2.0 KiB
C++
/**
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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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* Copyright (c) 2002-$CurrentYear$, Linden Research, Inc.
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* $License$
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*/
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#include "linden_common.h"
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#include <math.h>
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#include "llcriticaldamp.h"
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//-----------------------------------------------------------------------------
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// static members
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//-----------------------------------------------------------------------------
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LLFrameTimer LLCriticalDamp::sInternalTimer;
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std::map<F32, F32> LLCriticalDamp::sInterpolants;
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F32 LLCriticalDamp::sTimeDelta;
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//-----------------------------------------------------------------------------
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// LLCriticalDamp()
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//-----------------------------------------------------------------------------
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LLCriticalDamp::LLCriticalDamp()
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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 LLCriticalDamp::updateInterpolants()
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{
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sTimeDelta = sInternalTimer.getElapsedTimeAndResetF32();
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F32 time_constant;
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for (std::map<F32, F32>::iterator iter = sInterpolants.begin();
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iter != sInterpolants.end(); iter++)
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{
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time_constant = iter->first;
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F32 new_interpolant = 1.f - pow(2.f, -sTimeDelta / time_constant);
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new_interpolant = llclamp(new_interpolant, 0.f, 1.f);
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sInterpolants[time_constant] = new_interpolant;
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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 LLCriticalDamp::getInterpolant(const F32 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 && sInterpolants.count(time_constant))
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{
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return sInterpolants[time_constant];
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}
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F32 interpolant = 1.f - pow(2.f, -sTimeDelta / time_constant);
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interpolant = llclamp(interpolant, 0.f, 1.f);
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if (use_cache)
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{
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sInterpolants[time_constant] = interpolant;
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}
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return interpolant;
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}
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