96 lines
3.2 KiB
C++
96 lines
3.2 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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* $LicenseInfo:firstyear=2002&license=viewergpl$
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*
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* Copyright (c) 2002-2009, Linden Research, Inc.
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*
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* Second Life Viewer Source Code
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* The source code in this file ("Source Code") is provided by Linden Lab
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* to you under the terms of the GNU General Public License, version 2.0
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* ("GPL"), unless you have obtained a separate licensing agreement
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* ("Other License"), formally executed by you and Linden Lab. Terms of
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* the GPL can be found in doc/GPL-license.txt in this distribution, or
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* online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
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*
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* There are special exceptions to the terms and conditions of the GPL as
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* it is applied to this Source Code. View the full text of the exception
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* in the file doc/FLOSS-exception.txt in this software distribution, or
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* online at
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* http://secondlifegrid.net/programs/open_source/licensing/flossexception
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*
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* By copying, modifying or distributing this software, you acknowledge
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* that you have read and understood your obligations described above,
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* and agree to abide by those obligations.
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*
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* ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
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* WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
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* COMPLETENESS OR PERFORMANCE.
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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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//-----------------------------------------------------------------------------
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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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