Claw  1.7.3
symmetric_easing.tpp
1 /*
2  CLAW - a C++ Library Absolutely Wonderful
3 
4  CLAW is a free library without any particular aim but being useful to
5  anyone.
6 
7  Copyright (C) 2005-2011 Julien Jorge
8 
9  This library is free software; you can redistribute it and/or
10  modify it under the terms of the GNU Lesser General Public
11  License as published by the Free Software Foundation; either
12  version 2.1 of the License, or (at your option) any later version.
13 
14  This library is distributed in the hope that it will be useful,
15  but WITHOUT ANY WARRANTY; without even the implied warranty of
16  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  Lesser General Public License for more details.
18 
19  You should have received a copy of the GNU Lesser General Public
20  License along with this library; if not, write to the Free Software
21  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22  contact: julien.jorge@gamned.org
23 */
24 /**
25  * \file claw/tween/easing/impl/symmetric_easing.tpp
26  * \brief Implementation of the claw::tween::symmetric_easing class.
27  * \author Julien Jorge
28  */
29 
30 /*----------------------------------------------------------------------------*/
31 /**
32  * \brief Apply the easing at the beginning of the tweener.
33  * \param t The ratio of the date, in (0, 1), representing the total progression
34  * of the tweener.
35  */
36 template<double (*Function)(double)>
37 double claw::tween::symmetric_easing<Function>::ease_in( double t )
38 {
39  return Function(t);
40 } // symmetric_easing::ease_in()
41 
42 /*----------------------------------------------------------------------------*/
43 /**
44  * \brief Apply the easing at the end of the tweener.
45  * \param t The ratio of the date, in (0, 1), representing the total progression
46  * of the tweener.
47  */
48 template<double (*Function)(double)>
49 double claw::tween::symmetric_easing<Function>::ease_out( double t )
50 {
51  return 1 - ease_in( 1 - t );
52 } // symmetric_easing::ease_out()
53 
54 /*----------------------------------------------------------------------------*/
55 /**
56  * \brief Apply the easing at the beginning and the end of the tweener.
57  * \param t The ratio of the date, in (0, 1), representing the total progression
58  * of the tweener.
59  */
60 template<double (*Function)(double)>
61 double claw::tween::symmetric_easing<Function>::ease_in_out( double t )
62 {
63  if ( t < 0.5 )
64  return ease_in( 2 * t ) / 2;
65  else
66  return 0.5 + ease_out( 2 * t - 1 ) / 2;
67 } // symmetric_easing::ease_in_out()