nel/src/misc/mouse_smoother.cpp

   1 // NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
   2 // Copyright (C) 2010  Winch Gate Property Limited
   3 //
   4 // This program is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU Affero General Public License as
   6 // published by the Free Software Foundation, either version 3 of the
   7 // License, or (at your option) any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU Affero General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU Affero General Public License
  15 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 #include "stdmisc.h"
  18 #include "nel/misc/mouse_smoother.h"
  19
  20 #ifdef DEBUG_NEW
  21         #define new DEBUG_NEW
  22 #endif
  23
  24 namespace NLMISC
  25 {
  26
  27 // *******************************************************************************************
  28 /// build some hermite spline value, with the given points and tangents
  29 static inline void BuildHermiteVector(const NLMISC::CVector2f &P0,
  30                                                                           const NLMISC::CVector2f &P1,
  31                                                                           const NLMISC::CVector2f &T0,
  32                                                                           const NLMISC::CVector2f &T1,
  33                                                                           NLMISC::CVector2f &dest,
  34                                                                           float lambda
  35                                                                           )
  36 {
  37         const float lambda2 = lambda * lambda;
  38         const float lambda3 = lambda2 * lambda;
  39         const float h1 = 2 * lambda3 - 3 * lambda2 + 1;
  40         const float h2 = - 2 * lambda3 + 3 * lambda2;
  41         const float h3 = lambda3 - 2 * lambda2 + lambda;
  42         const float h4 = lambda3 - lambda2;
  43         /// just avoid some ctor calls here...
  44         dest.set(h1 * P0.x + h2 * P1.x + h3 * T0.x + h4 * T1.x,
  45                 h1 * P0.y + h2 * P1.y + h3 * T0.y + h4 * T1.y);
  46 }
  47
  48 // *******************************************************************************************
  49 CMouseSmoother::CMouseSmoother(double samplingPeriod /*=0.2f*/)
  50 {
  51         nlassert(samplingPeriod > 0);
  52         _SamplingPeriod = samplingPeriod;
  53         _Init = false;
  54 }
  55
  56
  57 // *******************************************************************************************
  58 void CMouseSmoother::setSamplingPeriod(double period)
  59 {
  60         if (period == _SamplingPeriod) return;
  61         reset();
  62         nlassert(_SamplingPeriod > 0);
  63         _SamplingPeriod = period;
  64 }
  65
  66
  67 // *******************************************************************************************
  68 NLMISC::CVector2f CMouseSmoother::samplePos(const CVector2f &wantedPos, double date)
  69 {
  70         if (!_Init)
  71         {
  72                 _Sample[0] = _Sample[1] = _Sample[2] = _Sample[3] = CSample(date, wantedPos);
  73                 _Init = true;
  74         }
  75         else
  76         {
  77                 // see if enough time has elapsed since last sample
  78                 if (date - _Sample[3].Date >= _SamplingPeriod)
  79                 {
  80                         uint numSamples = (uint) floor((date - _Sample[3].Date) / _SamplingPeriod);
  81                         numSamples = std::min(numSamples, (uint) 4);
  82                         for(uint k = 0; k < numSamples; ++k)
  83                         {
  84                                 // add a new sample
  85                                 _Sample[0] = _Sample[1];
  86                                 _Sample[1] = _Sample[2];
  87                                 _Sample[2] = _Sample[3];
  88                                 _Sample[3] = CSample(date, wantedPos);
  89                         }
  90                 }
  91                 else if (date == _Sample[3].Date)
  92                 {
  93                         // update cur pos
  94                         _Sample[3] = CSample(date, wantedPos);
  95                 }
  96         }
  97         if (_Sample[1].Pos.x == _Sample[2].Pos.x &&
  98                 _Sample[1].Pos.y == _Sample[2].Pos.y
  99            )
 100         {
 101                 // special case : if pointer hasn't moved, allow a discontinuity of speed
 102                 return _Sample[2].Pos;
 103         }
 104         double evalDate = date - 2 * _SamplingPeriod;
 105         clamp(evalDate, _Sample[1].Date, _Sample[2].Date);
 106         CVector2f t0;
 107         double dt = _Sample[2].Date - _Sample[1].Date;
 108         if (_Sample[2].Date != _Sample[0].Date)
 109         {
 110                 t0 = (float) dt * (_Sample[2].Pos - _Sample[0].Pos) / (float) (_Sample[2].Date - _Sample[0].Date);
 111         }
 112         else
 113         {
 114                 t0= NLMISC::CVector::Null;
 115         }
 116         CVector2f t1;
 117         if (_Sample[3].Date != _Sample[1].Date)
 118         {
 119                 t1 = (float) dt * (_Sample[3].Pos - _Sample[1].Pos) / (float) (_Sample[3].Date - _Sample[1].Date);
 120         }
 121         else
 122         {
 123                 t1= NLMISC::CVector::Null;
 124         }
 125         NLMISC::CVector2f result;
 126         if (dt == 0) return _Sample[2].Pos;
 127         BuildHermiteVector(_Sample[1].Pos, _Sample[2].Pos, t0, t1, result, (float) ((evalDate - _Sample[1].Date) / dt));
 128         return result;
 129 }
 130
 131 // *******************************************************************************************
 132 void CMouseSmoother::reset()
 133 {
 134         _Init = false;
 135 }
 136
 137 } // NLMISC