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| 1 <!DOCTYPE html> | |
| 2 <!-- | |
| 3 Copyright (c) 2014 The Chromium Authors. All rights reserved. | |
| 4 Use of this source code is governed by a BSD-style license that can be | |
| 5 found in the LICENSE file. | |
| 6 --> | |
| 7 <link rel="import" href="/tracing/base/base.html"> | |
| 8 <script src="/gl-matrix-min.js"></script> | |
| 9 | |
| 10 <script> | |
| 11 'use strict'; | |
| 12 | |
| 13 // In node, the script-src for gl-matrix-min above brings in glmatrix into | |
| 14 // a module, instead of into the global scope. Whereas, Tracing code | |
| 15 // assumes that glMatrix is in the global scope. So, in Node only, we | |
| 16 // require() it in, and then take all its exports and shove them into the | |
| 17 // global scope by hand. | |
| 18 (function(global) { | |
| 19 if (tr.isNode) { | |
| 20 var glMatrixAbsPath = HTMLImportsLoader.hrefToAbsolutePath( | |
| 21 '/gl-matrix-min.js'); | |
| 22 var glMatrixModule = require(glMatrixAbsPath); | |
| 23 for (var exportName in glMatrixModule) { | |
| 24 global[exportName] = glMatrixModule[exportName]; | |
| 25 } | |
| 26 } | |
| 27 })(this); | |
| 28 </script> | |
| 29 | |
| 30 <script> | |
| 31 'use strict'; | |
| 32 | |
| 33 tr.exportTo('tr.b', function() { | |
| 34 var PREFERRED_NUMBER_SERIES_MULTIPLIERS = [1, 2, 5, 10]; | |
| 35 | |
| 36 /* Returns true when x and y are within delta of each other. */ | |
| 37 function approximately(x, y, delta) { | |
| 38 if (delta === undefined) | |
| 39 delta = 1e-9; | |
| 40 return Math.abs(x - y) < delta; | |
| 41 } | |
| 42 | |
| 43 function clamp(x, lo, hi) { | |
| 44 return Math.min(Math.max(x, lo), hi); | |
| 45 } | |
| 46 | |
| 47 function lerp(percentage, lo, hi) { | |
| 48 var range = hi - lo; | |
| 49 return lo + percentage * range; | |
| 50 } | |
| 51 | |
| 52 function normalize(value, lo, hi) { | |
| 53 return (value - lo) / (hi - lo); | |
| 54 } | |
| 55 | |
| 56 function deg2rad(deg) { | |
| 57 return (Math.PI * deg) / 180.0; | |
| 58 } | |
| 59 | |
| 60 /* The Gauss error function gives the probability that a measurement (which is | |
| 61 * under the influence of normally distributed errors with standard deviation | |
| 62 * sigma = 1) is less than x from the mean value of the standard normal | |
| 63 * distribution. | |
| 64 * https://www.desmos.com/calculator/t1v4bdpske | |
| 65 * | |
| 66 * @param {number} x A tolerance for error. | |
| 67 * @return {number} The probability that a measurement is less than |x| from | |
| 68 * the mean value of the standard normal distribution. | |
| 69 */ | |
| 70 function erf(x) { | |
| 71 // save the sign of x | |
| 72 // erf(-x) = -erf(x); | |
| 73 var sign = (x >= 0) ? 1 : -1; | |
| 74 x = Math.abs(x); | |
| 75 | |
| 76 // constants | |
| 77 var a1 = 0.254829592; | |
| 78 var a2 = -0.284496736; | |
| 79 var a3 = 1.421413741; | |
| 80 var a4 = -1.453152027; | |
| 81 var a5 = 1.061405429; | |
| 82 var p = 0.3275911; | |
| 83 | |
| 84 // Abramowitz and Stegun formula 7.1.26 | |
| 85 // maximum error: 1.5e-7 | |
| 86 var t = 1.0 / (1.0 + p * x); | |
| 87 var y = 1.0 - (((((a5 * t + a4) * t) + a3) * t + a2) * t + a1) * t * | |
| 88 Math.exp(-x * x); | |
| 89 return sign * y; | |
| 90 } | |
| 91 | |
| 92 var tmpVec2 = vec2.create(); | |
| 93 var tmpVec2b = vec2.create(); | |
| 94 var tmpVec4 = vec4.create(); | |
| 95 var tmpMat2d = mat2d.create(); | |
| 96 | |
| 97 vec2.createFromArray = function(arr) { | |
| 98 if (arr.length !== 2) | |
| 99 throw new Error('Should be length 2'); | |
| 100 var v = vec2.create(); | |
| 101 vec2.set(v, arr[0], arr[1]); | |
| 102 return v; | |
| 103 }; | |
| 104 | |
| 105 vec2.createXY = function(x, y) { | |
| 106 var v = vec2.create(); | |
| 107 vec2.set(v, x, y); | |
| 108 return v; | |
| 109 }; | |
| 110 | |
| 111 vec2.toString = function(a) { | |
| 112 return '[' + a[0] + ', ' + a[1] + ']'; | |
| 113 }; | |
| 114 | |
| 115 vec2.addTwoScaledUnitVectors = function(out, u1, scale1, u2, scale2) { | |
| 116 // out = u1 * scale1 + u2 * scale2 | |
| 117 vec2.scale(tmpVec2, u1, scale1); | |
| 118 vec2.scale(tmpVec2b, u2, scale2); | |
| 119 vec2.add(out, tmpVec2, tmpVec2b); | |
| 120 }; | |
| 121 | |
| 122 vec2.interpolatePiecewiseFunction = function(points, x) { | |
| 123 if (x < points[0][0]) | |
| 124 return points[0][1]; | |
| 125 for (var i = 1; i < points.length; ++i) { | |
| 126 if (x < points[i][0]) { | |
| 127 var percent = normalize(x, points[i - 1][0], points[i][0]); | |
| 128 return lerp(percent, points[i - 1][1], points[i][1]); | |
| 129 } | |
| 130 } | |
| 131 return points[points.length - 1][1]; | |
| 132 }; | |
| 133 | |
| 134 vec3.createXYZ = function(x, y, z) { | |
| 135 var v = vec3.create(); | |
| 136 vec3.set(v, x, y, z); | |
| 137 return v; | |
| 138 }; | |
| 139 | |
| 140 vec3.toString = function(a) { | |
| 141 return 'vec3(' + a[0] + ', ' + a[1] + ', ' + a[2] + ')'; | |
| 142 }; | |
| 143 | |
| 144 mat2d.translateXY = function(out, x, y) { | |
| 145 vec2.set(tmpVec2, x, y); | |
| 146 mat2d.translate(out, out, tmpVec2); | |
| 147 }; | |
| 148 | |
| 149 mat2d.scaleXY = function(out, x, y) { | |
| 150 vec2.set(tmpVec2, x, y); | |
| 151 mat2d.scale(out, out, tmpVec2); | |
| 152 }; | |
| 153 | |
| 154 vec4.unitize = function(out, a) { | |
| 155 out[0] = a[0] / a[3]; | |
| 156 out[1] = a[1] / a[3]; | |
| 157 out[2] = a[2] / a[3]; | |
| 158 out[3] = 1; | |
| 159 return out; | |
| 160 }; | |
| 161 | |
| 162 vec2.copyFromVec4 = function(out, a) { | |
| 163 vec4.unitize(tmpVec4, a); | |
| 164 vec2.copy(out, tmpVec4); | |
| 165 }; | |
| 166 | |
| 167 /** | |
| 168 * @param {number} x | |
| 169 * @param {number=} opt_base Defaults to 10 | |
| 170 * @return {number} | |
| 171 */ | |
| 172 function logOrLog10(x, base) { | |
| 173 if (base === 10) return Math.log10(x); | |
| 174 return Math.log(x) / Math.log(base); | |
| 175 } | |
| 176 | |
| 177 /** | |
| 178 * @param {number} x | |
| 179 * @param {number=} opt_base Defaults to 10 | |
| 180 * @return {number} | |
| 181 */ | |
| 182 function lesserPower(x, opt_base) { | |
| 183 var base = opt_base || 10; | |
| 184 return Math.pow(base, Math.floor(logOrLog10(x, base))); | |
| 185 } | |
| 186 | |
| 187 /** | |
| 188 * @param {number} x | |
| 189 * @param {number=} opt_base Defaults to 10 | |
| 190 * @return {number} | |
| 191 */ | |
| 192 function greaterPower(x, opt_base) { | |
| 193 var base = opt_base || 10; | |
| 194 return Math.pow(base, Math.ceil(logOrLog10(x, base))); | |
| 195 } | |
| 196 | |
| 197 function lesserWholeNumber(x) { | |
| 198 if (x === 0) return 0; | |
| 199 const pow10 = (x < 0) ? -lesserPower(-x) : lesserPower(x); | |
| 200 return pow10 * Math.floor(x / pow10); | |
| 201 } | |
| 202 | |
| 203 function greaterWholeNumber(x) { | |
| 204 if (x === 0) return 0; | |
| 205 const pow10 = (x < 0) ? -lesserPower(-x) : lesserPower(x); | |
| 206 return pow10 * Math.ceil(x / pow10); | |
| 207 } | |
| 208 | |
| 209 /** | |
| 210 * Uses the 1-2-5 series to find the closest prefered number to min | |
| 211 * whose absolute value is at least the absolute value of |min|. | |
| 212 * https://en.wikipedia.org/wiki/Preferred_number | |
| 213 */ | |
| 214 function preferredNumberLargerThanMin(min) { | |
| 215 var absMin = Math.abs(min); | |
| 216 // The conservative guess is the largest power of 10 less than | |
| 217 // or equal to |absMin|. | |
| 218 var conservativeGuess = tr.b.lesserPower(absMin); | |
| 219 var minPreferedNumber = undefined; | |
| 220 for (var multiplier of PREFERRED_NUMBER_SERIES_MULTIPLIERS) { | |
| 221 var tightenedGuess = conservativeGuess * multiplier; | |
| 222 if (tightenedGuess >= absMin) { | |
| 223 minPreferedNumber = tightenedGuess; | |
| 224 break; | |
| 225 } | |
| 226 } | |
| 227 if (minPreferedNumber === undefined) { | |
| 228 throw new Error('Could not compute preferred number for ' + min); | |
| 229 } | |
| 230 if (min < 0) minPreferedNumber *= -1; | |
| 231 return minPreferedNumber; | |
| 232 } | |
| 233 | |
| 234 return { | |
| 235 approximately, | |
| 236 clamp, | |
| 237 lerp, | |
| 238 normalize, | |
| 239 deg2rad, | |
| 240 erf, | |
| 241 lesserPower, | |
| 242 greaterPower, | |
| 243 lesserWholeNumber, | |
| 244 greaterWholeNumber, | |
| 245 preferredNumberLargerThanMin, | |
| 246 }; | |
| 247 }); | |
| 248 </script> | |
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Chromium Code Reviews
Issue 2771723003:
[tracing] Move math utilities from base into their own subdirectory (attempt 2) (Closed)
