language: C++ 4.7.2 (gcc-4.7.2)
date: 82 days 1 hour ago
link:
visibility: public 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183

#include "EaseEquations.h"
#include <cmath>
 
const float FloatPI = 3.14159f;
 
//While I wrote the C++ code here, most of the algorithms used were created by Robert Penner. 
 
/*
    TERMS OF USE - EASING EQUATIONS
    
    Open source under the BSD License. 
    
    Copyright © 2001 Robert Penner
    All rights reserved.
    
    Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are 
    met:
    
     - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
    
     - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the 
       documentation and/or other materials provided with the distribution.
       
     - Neither the name of the author nor the names of contributors may be used to endorse or promote products derived from this software 
       without specific prior written permission.
    
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR 
    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 
    AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 
    OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
    OF SUCH DAMAGE.
*/
 
float QuadraticEase(float position)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return (position * position); //PowerEase(position, 2.0f);
}
 
float CubicEase(float position)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return (position * position * position); //PowerEase(position, 3.0f);
}
 
float QuarticEase(float position)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return (position * position * position * position); //PowerEase(position, 4.0f);
}
 
float QuinticEase(float position)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return (position * position * position * position * position); //PowerEase(position, 5.0f);
}
 
float PowerEase(float position, float power)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return std::pow(position, power);
}
 
float ExponentialEase(float position, float exponent)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return ((std::exp(exponent * position) - 1.0f) / (std::exp(exponent) - 1.0f));
}
 
float CircleEase(float position)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return 1.0f - sqrtf(1.0f - std::pow(position, 2.0f));
}
 
float SineEase(float position)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return -1.0f * std::cos(position * (FloatPI/2.0f)) + 1.0f;
}
 
float BounceEase(float position)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    //Because this equation is EaseOut, we have to invert the input and the output to make it EaseIn.
    position = 1.0f - position;
    
    //I don't know the purpose this constant serves in the original ease equation.
    const float UnknownVar = 7.5625f;
    //1.0f for the half-bounce, 1.0f, 0.5f, and 0.25f, for the other bounces.
    const float TotalSize = 2.75f;
    
    if(position < (1.0f / TotalSize)) 
    {
        return 1.0f - (UnknownVar * position * position);
    }
    else if(position < (2.0f / TotalSize))
    {
        position -= (1.5f / TotalSize);
        return 1.0f - (UnknownVar * position * position + 0.75f);
    }
    else if(position < (2.5f / TotalSize))
    {
        position -= (2.25f / TotalSize);
        return 1.0f - (UnknownVar * position * position + 0.9375f); //0.75 + (0.75 * 0.25)
    }
    else
    {
        position -= (2.625f / TotalSize);
        return 1.0f - (UnknownVar * position * position + 0.984375f); //(0.75 + (0.75 * 0.25)) + (0.75f * 0.0625f)
    }
}
 
float ElasticEase(float position, float period)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return -std::pow(2, 10 * (position - 1.0f)) * std::sin(((position - 1.0f) - period / 4.0f) * 2.0f * FloatPI / period);
}
 
float BackEase(float position, float amplitude)
{
    //Optimization for end points, which are the most common spots.
    if(position == 0.0f || position == 1.0f)
    {
        return position;
    }
    
    return std::pow(position, 3.0f) - (position * amplitude * std::sin(position * FloatPI));
}
Useful Easing functions, ported from the Robert Penning equations.