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 25namespace android { 26namespace uirenderer { 27 28Interpolator* Interpolator::createDefaultInterpolator() { 29 return new AccelerateDecelerateInterpolator(); 30} 31 32float AccelerateDecelerateInterpolator::interpolate(float input) { 33 return (float)(cosf((input + 1) * M_PI) / 2.0f) + 0.5f; 34} 35 36float AccelerateInterpolator::interpolate(float input) { 37 if (mFactor == 1.0f) { 38 return input * input; 39 } else { 40 return pow(input, mDoubleFactor); 41 } 42} 43 44float AnticipateInterpolator::interpolate(float t) { 45 return t * t * ((mTension + 1) * t - mTension); 46} 47 48static float a(float t, float s) { 49 return t * t * ((s + 1) * t - s); 50} 51 52static float o(float t, float s) { 53 return t * t * ((s + 1) * t + s); 54} 55 56float AnticipateOvershootInterpolator::interpolate(float t) { 57 if (t < 0.5f) return 0.5f * a(t * 2.0f, mTension); 58 else return 0.5f * (o(t * 2.0f - 2.0f, mTension) + 2.0f); 59} 60 61static float bounce(float t) { 62 return t * t * 8.0f; 63} 64 65float BounceInterpolator::interpolate(float t) { 66 t *= 1.1226f; 67 if (t < 0.3535f) return bounce(t); 68 else if (t < 0.7408f) return bounce(t - 0.54719f) + 0.7f; 69 else if (t < 0.9644f) return bounce(t - 0.8526f) + 0.9f; 70 else return bounce(t - 1.0435f) + 0.95f; 71} 72 73float CycleInterpolator::interpolate(float input) { 74 return sinf(2 * mCycles * M_PI * input); 75} 76 77float DecelerateInterpolator::interpolate(float input) { 78 float result; 79 if (mFactor == 1.0f) { 80 result = 1.0f - (1.0f - input) * (1.0f - input); 81 } else { 82 result = 1.0f - pow((1.0f - input), 2 * mFactor); 83 } 84 return result; 85} 86 87float OvershootInterpolator::interpolate(float t) { 88 t -= 1.0f; 89 return t * t * ((mTension + 1) * t + mTension) + 1.0f; 90} 91 92float PathInterpolator::interpolate(float t) { 93 if (t <= 0) { 94 return 0; 95 } else if (t >= 1) { 96 return 1; 97 } 98 // Do a binary search for the correct x to interpolate between. 99 size_t startIndex = 0; 100 size_t endIndex = mX.size() - 1; 101 102 while (endIndex > startIndex + 1) { 103 int midIndex = (startIndex + endIndex) / 2; 104 if (t < mX[midIndex]) { 105 endIndex = midIndex; 106 } else { 107 startIndex = midIndex; 108 } 109 } 110 111 float xRange = mX[endIndex] - mX[startIndex]; 112 if (xRange == 0) { 113 return mY[startIndex]; 114 } 115 116 float tInRange = t - mX[startIndex]; 117 float fraction = tInRange / xRange; 118 119 float startY = mY[startIndex]; 120 float endY = mY[endIndex]; 121 return startY + (fraction * (endY - startY)); 122 123} 124 125LUTInterpolator::LUTInterpolator(float* values, size_t size) 126 : mValues(values) 127 , mSize(size) { 128} 129 130LUTInterpolator::~LUTInterpolator() { 131} 132 133float LUTInterpolator::interpolate(float input) { 134 // lut position should only be at the end of the table when input is 1f. 135 float lutpos = input * (mSize - 1); 136 if (lutpos >= (mSize - 1)) { 137 return mValues[mSize - 1]; 138 } 139 140 float ipart, weight; 141 weight = modff(lutpos, &ipart); 142 143 int i1 = (int) ipart; 144 int i2 = std::min(i1 + 1, (int) mSize - 1); 145 146 LOG_ALWAYS_FATAL_IF(i1 < 0 || i2 < 0, "negatives in interpolation!" 147 " i1=%d, i2=%d, input=%f, lutpos=%f, size=%zu, values=%p, ipart=%f, weight=%f", 148 i1, i2, input, lutpos, mSize, mValues.get(), ipart, weight); 149 150 float v1 = mValues[i1]; 151 float v2 = mValues[i2]; 152 153 return MathUtils::lerp(v1, v2, weight); 154} 155 156 157} /* namespace uirenderer */ 158} /* namespace android */ 159