1 /*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "Interpolator.h"
18
19 #include <algorithm>
20
21 #include <log/log.h>
22
23 #include "utils/MathUtils.h"
24
25 namespace android {
26 namespace uirenderer {
27
createDefaultInterpolator()28 Interpolator* Interpolator::createDefaultInterpolator() {
29 return new AccelerateDecelerateInterpolator();
30 }
31
interpolate(float input)32 float AccelerateDecelerateInterpolator::interpolate(float input) {
33 return (float)(cosf((input + 1) * M_PI) / 2.0f) + 0.5f;
34 }
35
interpolate(float input)36 float AccelerateInterpolator::interpolate(float input) {
37 if (mFactor == 1.0f) {
38 return input * input;
39 } else {
40 return pow(input, mDoubleFactor);
41 }
42 }
43
interpolate(float t)44 float AnticipateInterpolator::interpolate(float t) {
45 return t * t * ((mTension + 1) * t - mTension);
46 }
47
a(float t,float s)48 static float a(float t, float s) {
49 return t * t * ((s + 1) * t - s);
50 }
51
o(float t,float s)52 static float o(float t, float s) {
53 return t * t * ((s + 1) * t + s);
54 }
55
interpolate(float t)56 float AnticipateOvershootInterpolator::interpolate(float t) {
57 if (t < 0.5f)
58 return 0.5f * a(t * 2.0f, mTension);
59 else
60 return 0.5f * (o(t * 2.0f - 2.0f, mTension) + 2.0f);
61 }
62
bounce(float t)63 static float bounce(float t) {
64 return t * t * 8.0f;
65 }
66
interpolate(float t)67 float BounceInterpolator::interpolate(float t) {
68 t *= 1.1226f;
69 if (t < 0.3535f)
70 return bounce(t);
71 else if (t < 0.7408f)
72 return bounce(t - 0.54719f) + 0.7f;
73 else if (t < 0.9644f)
74 return bounce(t - 0.8526f) + 0.9f;
75 else
76 return bounce(t - 1.0435f) + 0.95f;
77 }
78
interpolate(float input)79 float CycleInterpolator::interpolate(float input) {
80 return sinf(2 * mCycles * M_PI * input);
81 }
82
interpolate(float input)83 float DecelerateInterpolator::interpolate(float input) {
84 float result;
85 if (mFactor == 1.0f) {
86 result = 1.0f - (1.0f - input) * (1.0f - input);
87 } else {
88 result = 1.0f - pow((1.0f - input), 2 * mFactor);
89 }
90 return result;
91 }
92
interpolate(float t)93 float OvershootInterpolator::interpolate(float t) {
94 t -= 1.0f;
95 return t * t * ((mTension + 1) * t + mTension) + 1.0f;
96 }
97
interpolate(float t)98 float PathInterpolator::interpolate(float t) {
99 if (t <= 0) {
100 return 0;
101 } else if (t >= 1) {
102 return 1;
103 }
104 // Do a binary search for the correct x to interpolate between.
105 size_t startIndex = 0;
106 size_t endIndex = mX.size() - 1;
107
108 while (endIndex > startIndex + 1) {
109 int midIndex = (startIndex + endIndex) / 2;
110 if (t < mX[midIndex]) {
111 endIndex = midIndex;
112 } else {
113 startIndex = midIndex;
114 }
115 }
116
117 float xRange = mX[endIndex] - mX[startIndex];
118 if (xRange == 0) {
119 return mY[startIndex];
120 }
121
122 float tInRange = t - mX[startIndex];
123 float fraction = tInRange / xRange;
124
125 float startY = mY[startIndex];
126 float endY = mY[endIndex];
127 return startY + (fraction * (endY - startY));
128 }
129
LUTInterpolator(float * values,size_t size)130 LUTInterpolator::LUTInterpolator(float* values, size_t size) : mValues(values), mSize(size) {}
131
~LUTInterpolator()132 LUTInterpolator::~LUTInterpolator() {}
133
interpolate(float input)134 float LUTInterpolator::interpolate(float input) {
135 // lut position should only be at the end of the table when input is 1f.
136 float lutpos = input * (mSize - 1);
137 if (lutpos >= (mSize - 1)) {
138 return mValues[mSize - 1];
139 }
140
141 float ipart, weight;
142 weight = modff(lutpos, &ipart);
143
144 int i1 = (int)ipart;
145 int i2 = std::min(i1 + 1, (int)mSize - 1);
146
147 LOG_ALWAYS_FATAL_IF(
148 i1 < 0 || i2 < 0,
149 "negatives in interpolation!"
150 " i1=%d, i2=%d, input=%f, lutpos=%f, size=%zu, values=%p, ipart=%f, weight=%f",
151 i1, i2, input, lutpos, mSize, mValues.get(), ipart, weight);
152
153 float v1 = mValues[i1];
154 float v2 = mValues[i2];
155
156 return MathUtils::lerp(v1, v2, weight);
157 }
158
159 } /* namespace uirenderer */
160 } /* namespace android */
161