src/movement.cpp

   1 /*
   2   Copyright (c) 2006 Paolo Capriotti <p.capriotti@gmail.com>
   3             (c) 2006 Maurizio Monge <maurizio.monge@kdemail.net>
   4
   5   This program is free software; you can redistribute it and/or modify
   6   it under the terms of the GNU General Public License as published by
   7   the Free Software Foundation; either version 2 of the License, or
   8   (at your option) any later version.
   9 */
  10
  11 #include "movement.h"
  12 #include "common.h"
  13 #include <cmath>
  14
  15 using std::abs;
  16 #define QUINTIC_SIGMOID
  17
  18 double Movement::sigmoid(double t) {
  19 #ifdef CUBIC_SIGMOID
  20   return -2 * pow(t - 0.5, 3) + 1.5 * t - 0.25;
  21 #else
  22   return 6 * pow(t - 0.5, 5) - 5 * pow(t, 3) + 7.5 * t * t - 15 * 0.125 * t + 3.0 / 16;
  23 #endif
  24 }
  25
  26 double Movement::half_sigmoid(double t) {
  27   // use the second half of the sigmoid parameterization
  28   return sigmoid(0.5 * (t + 1));
  29 }
  30
  31 LinearMovement::LinearMovement(const QPoint& from, const QPoint& to, bool /*rotate*/)
  32 : m_from(from)
  33 , m_velocity(to - from) { }
  34
  35 QPoint LinearMovement::pos(double t) const {
  36   return m_from + m_velocity * t;
  37 }
  38
  39 LMovement::LMovement(const QPoint& from, const QPoint& to, bool rotate)
  40 : m_from(from)
  41 , m_velocity(to - from)
  42 , m_rotate(rotate) {
  43   if (abs(static_cast<double>(m_velocity.x())) >=
  44       abs(static_cast<double>(m_velocity.y()))) {
  45     m_x = LMovement::nonlinear;
  46     m_y = LMovement::linear;
  47   }
  48   else {
  49     m_y = LMovement::nonlinear;
  50     m_x = LMovement::linear;
  51   }
  52 }
  53
  54 double LMovement::nonlinear(double t) {
  55   return (exp( (double)(3 * t) ) - 1) / (exp( (double)3 ) - 1);
  56 }
  57
  58 QPoint LMovement::pos(double t) const {
  59   return m_from + QPoint(
  60     static_cast<int>(m_velocity.x() * m_x(t)),
  61     static_cast<int>(m_velocity.y() * m_y(t)));
  62 }
  63
  64 double LMovement::rotation(double t) const {
  65   if(!m_rotate)
  66     return 0.0;
  67
  68   double r = (1.0-cos(t*M_PI))*M_PI;
  69   return m_velocity.x() >= 0 ? r : -r;
  70 }
  71