spectrum.cpp

/*

Copyright 2018 Lingqi Yan

This file is part of WaveOpticsBrdf.

WaveOpticsBrdf is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

WaveOpticsBrdf is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with WaveOpticsBrdf.  If not, see <https://www.gnu.org/licenses/>.

*/

/*
    This file is part of Mitsuba, a physically based rendering system.

    Copyright (c) 2007-2014 by Wenzel Jakob and others.

    Mitsuba is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License Version 3
    as published by the Free Software Foundation.

    Mitsuba is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program. If not, see <http://www.gnu.org/licenses/>.
*/

#include <cmath>
#include "spectrum.h"
using namespace std;

float CIE_X[SPECTRUM_SAMPLES];
float CIE_Y[SPECTRUM_SAMPLES];
float CIE_Z[SPECTRUM_SAMPLES];
float CIE_normalization;

void SpectrumInit() {
    for (size_t i = 0; i < SPECTRUM_SAMPLES; ++i) {
        double lambda = (i + 0.5) / SPECTRUM_SAMPLES * (0.7 - 0.3) + 0.3;
        
        double closestDist = 10000.0;
        int closestIndex = -1;
        for (int j = 0; j < CIE_samples; j++) {
            double lambdaSample = CIE_wavelengths[j] / 1000.0;
            if (fabs(lambdaSample - lambda) <= closestDist) {
                closestDist = fabs(lambdaSample - lambda);
                closestIndex = j;
            }
        }
//        printf("%d\n", closestIndex);

        CIE_X[i] = CIE_X_entries[closestIndex] * (0.7 - 0.3) / SPECTRUM_SAMPLES;
        CIE_Y[i] = CIE_Y_entries[closestIndex] * (0.7 - 0.3) / SPECTRUM_SAMPLES;
        CIE_Z[i] = CIE_Z_entries[closestIndex] * (0.7 - 0.3) / SPECTRUM_SAMPLES;
    }

    CIE_normalization = 0.0f;
    for (size_t i=0; i<SPECTRUM_SAMPLES; ++i)
        CIE_normalization += CIE_Y[i];
    CIE_normalization = 1.0f / CIE_normalization;
}

void SpectrumToXYZ(const vector<float> &s, float &x, float &y, float &z) {
    x = y = z = 0.0f;
    for (size_t i = 0; i < SPECTRUM_SAMPLES; ++i) {
        x += CIE_X[i] * s[i];
        y += CIE_Y[i] * s[i];
        z += CIE_Z[i] * s[i];
    }
    x *= CIE_normalization;
    y *= CIE_normalization;
    z *= CIE_normalization;
    // if (x != 0.0 && y != 0.0 && z != 0.0)
    //     printf("%f %f %f\n", x, y, z);
}

void XYZToRGB(float x, float y, float z, float &r, float &g, float &b) {
    /* Convert from XYZ tristimulus values to ITU-R Rec. BT.709 linear RGB */
    r =  3.240479f * x + -1.537150f * y + -0.498535f * z;
    g = -0.969256f * x +  1.875991f * y +  0.041556f * z;
    b =  0.055648f * x + -0.204043f * y +  1.057311f * z;
}

void SpectrumToRGB(const vector<float> &s, float &r, float &g, float &b) {
    float x, y, z;
    SpectrumToXYZ(s, x, y, z);
    XYZToRGB(x, y, z, r, g, b);
}

const float CIE_wavelengths[CIE_samples] = {
    360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373,
    374, 375, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385, 386, 387,
    388, 389, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399, 400, 401,
    402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415,
    416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426, 427, 428, 429,
    430, 431, 432, 433, 434, 435, 436, 437, 438, 439, 440, 441, 442, 443,
    444, 445, 446, 447, 448, 449, 450, 451, 452, 453, 454, 455, 456, 457,
    458, 459, 460, 461, 462, 463, 464, 465, 466, 467, 468, 469, 470, 471,
    472, 473, 474, 475, 476, 477, 478, 479, 480, 481, 482, 483, 484, 485,
    486, 487, 488, 489, 490, 491, 492, 493, 494, 495, 496, 497, 498, 499,
    500, 501, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 512, 513,
    514, 515, 516, 517, 518, 519, 520, 521, 522, 523, 524, 525, 526, 527,
    528, 529, 530, 531, 532, 533, 534, 535, 536, 537, 538, 539, 540, 541,
    542, 543, 544, 545, 546, 547, 548, 549, 550, 551, 552, 553, 554, 555,
    556, 557, 558, 559, 560, 561, 562, 563, 564, 565, 566, 567, 568, 569,
    570, 571, 572, 573, 574, 575, 576, 577, 578, 579, 580, 581, 582, 583,
    584, 585, 586, 587, 588, 589, 590, 591, 592, 593, 594, 595, 596, 597,
    598, 599, 600, 601, 602, 603, 604, 605, 606, 607, 608, 609, 610, 611,
    612, 613, 614, 615, 616, 617, 618, 619, 620, 621, 622, 623, 624, 625,
    626, 627, 628, 629, 630, 631, 632, 633, 634, 635, 636, 637, 638, 639,
    640, 641, 642, 643, 644, 645, 646, 647, 648, 649, 650, 651, 652, 653,
    654, 655, 656, 657, 658, 659, 660, 661, 662, 663, 664, 665, 666, 667,
    668, 669, 670, 671, 672, 673, 674, 675, 676, 677, 678, 679, 680, 681,
    682, 683, 684, 685, 686, 687, 688, 689, 690, 691, 692, 693, 694, 695,
    696, 697, 698, 699, 700, 701, 702, 703, 704, 705, 706, 707, 708, 709,
    710, 711, 712, 713, 714, 715, 716, 717, 718, 719, 720, 721, 722, 723,
    724, 725, 726, 727, 728, 729, 730, 731, 732, 733, 734, 735, 736, 737,
    738, 739, 740, 741, 742, 743, 744, 745, 746, 747, 748, 749, 750, 751,
    752, 753, 754, 755, 756, 757, 758, 759, 760, 761, 762, 763, 764, 765,
    766, 767, 768, 769, 770, 771, 772, 773, 774, 775, 776, 777, 778, 779,
    780, 781, 782, 783, 784, 785, 786, 787, 788, 789, 790, 791, 792, 793,
    794, 795, 796, 797, 798, 799, 800, 801, 802, 803, 804, 805, 806, 807,
    808, 809, 810, 811, 812, 813, 814, 815, 816, 817, 818, 819, 820, 821,
    822, 823, 824, 825, 826, 827, 828, 829, 830 };

const float CIE_X_entries[CIE_samples] = {
    0.0001299000, 0.0001458470, 0.0001638021, 0.0001840037,
    0.0002066902, 0.0002321000, 0.0002607280, 0.0002930750,
    0.0003293880, 0.0003699140, 0.0004149000, 0.0004641587,
    0.0005189860, 0.0005818540, 0.0006552347, 0.0007416000,
    0.0008450296, 0.0009645268, 0.001094949, 0.001231154,
    0.001368000, 0.001502050, 0.001642328, 0.001802382,
    0.001995757, 0.002236000, 0.002535385, 0.002892603,
    0.003300829, 0.003753236, 0.004243000, 0.004762389,
    0.005330048, 0.005978712, 0.006741117, 0.007650000,
    0.008751373, 0.01002888, 0.01142170, 0.01286901,
    0.01431000, 0.01570443, 0.01714744, 0.01878122,
    0.02074801, 0.02319000, 0.02620736, 0.02978248,
    0.03388092, 0.03846824, 0.04351000, 0.04899560,
    0.05502260, 0.06171880, 0.06921200, 0.07763000,
    0.08695811, 0.09717672, 0.1084063, 0.1207672,
    0.1343800, 0.1493582, 0.1653957, 0.1819831,
    0.1986110, 0.2147700, 0.2301868, 0.2448797,
    0.2587773, 0.2718079, 0.2839000, 0.2949438,
    0.3048965, 0.3137873, 0.3216454, 0.3285000,
    0.3343513, 0.3392101, 0.3431213, 0.3461296,
    0.3482800, 0.3495999, 0.3501474, 0.3500130,
    0.3492870, 0.3480600, 0.3463733, 0.3442624,
    0.3418088, 0.3390941, 0.3362000, 0.3331977,
    0.3300411, 0.3266357, 0.3228868, 0.3187000,
    0.3140251, 0.3088840, 0.3032904, 0.2972579,
    0.2908000, 0.2839701, 0.2767214, 0.2689178,
    0.2604227, 0.2511000, 0.2408475, 0.2298512,
    0.2184072, 0.2068115, 0.1953600, 0.1842136,
    0.1733273, 0.1626881, 0.1522833, 0.1421000,
    0.1321786, 0.1225696, 0.1132752, 0.1042979,
    0.09564000, 0.08729955, 0.07930804, 0.07171776,
    0.06458099, 0.05795001, 0.05186211, 0.04628152,
    0.04115088, 0.03641283, 0.03201000, 0.02791720,
    0.02414440, 0.02068700, 0.01754040, 0.01470000,
    0.01216179, 0.009919960, 0.007967240, 0.006296346,
    0.004900000, 0.003777173, 0.002945320, 0.002424880,
    0.002236293, 0.002400000, 0.002925520, 0.003836560,
    0.005174840, 0.006982080, 0.009300000, 0.01214949,
    0.01553588, 0.01947752, 0.02399277, 0.02910000,
    0.03481485, 0.04112016, 0.04798504, 0.05537861,
    0.06327000, 0.07163501, 0.08046224, 0.08973996,
    0.09945645, 0.1096000, 0.1201674, 0.1311145,
    0.1423679, 0.1538542, 0.1655000, 0.1772571,
    0.1891400, 0.2011694, 0.2133658, 0.2257499,
    0.2383209, 0.2510668, 0.2639922, 0.2771017,
    0.2904000, 0.3038912, 0.3175726, 0.3314384,
    0.3454828, 0.3597000, 0.3740839, 0.3886396,
    0.4033784, 0.4183115, 0.4334499, 0.4487953,
    0.4643360, 0.4800640, 0.4959713, 0.5120501,
    0.5282959, 0.5446916, 0.5612094, 0.5778215,
    0.5945000, 0.6112209, 0.6279758, 0.6447602,
    0.6615697, 0.6784000, 0.6952392, 0.7120586,
    0.7288284, 0.7455188, 0.7621000, 0.7785432,
    0.7948256, 0.8109264, 0.8268248, 0.8425000,
    0.8579325, 0.8730816, 0.8878944, 0.9023181,
    0.9163000, 0.9297995, 0.9427984, 0.9552776,
    0.9672179, 0.9786000, 0.9893856, 0.9995488,
    1.0090892, 1.0180064, 1.0263000, 1.0339827,
    1.0409860, 1.0471880, 1.0524667, 1.0567000,
    1.0597944, 1.0617992, 1.0628068, 1.0629096,
    1.0622000, 1.0607352, 1.0584436, 1.0552244,
    1.0509768, 1.0456000, 1.0390369, 1.0313608,
    1.0226662, 1.0130477, 1.0026000, 0.9913675,
    0.9793314, 0.9664916, 0.9528479, 0.9384000,
    0.9231940, 0.9072440, 0.8905020, 0.8729200,
    0.8544499, 0.8350840, 0.8149460, 0.7941860,
    0.7729540, 0.7514000, 0.7295836, 0.7075888,
    0.6856022, 0.6638104, 0.6424000, 0.6215149,
    0.6011138, 0.5811052, 0.5613977, 0.5419000,
    0.5225995, 0.5035464, 0.4847436, 0.4661939,
    0.4479000, 0.4298613, 0.4120980, 0.3946440,
    0.3775333, 0.3608000, 0.3444563, 0.3285168,
    0.3130192, 0.2980011, 0.2835000, 0.2695448,
    0.2561184, 0.2431896, 0.2307272, 0.2187000,
    0.2070971, 0.1959232, 0.1851708, 0.1748323,
    0.1649000, 0.1553667, 0.1462300, 0.1374900,
    0.1291467, 0.1212000, 0.1136397, 0.1064650,
    0.09969044, 0.09333061, 0.08740000, 0.08190096,
    0.07680428, 0.07207712, 0.06768664, 0.06360000,
    0.05980685, 0.05628216, 0.05297104, 0.04981861,
    0.04677000, 0.04378405, 0.04087536, 0.03807264,
    0.03540461, 0.03290000, 0.03056419, 0.02838056,
    0.02634484, 0.02445275, 0.02270000, 0.02108429,
    0.01959988, 0.01823732, 0.01698717, 0.01584000,
    0.01479064, 0.01383132, 0.01294868, 0.01212920,
    0.01135916, 0.01062935, 0.009938846, 0.009288422,
    0.008678854, 0.008110916, 0.007582388, 0.007088746,
    0.006627313, 0.006195408, 0.005790346, 0.005409826,
    0.005052583, 0.004717512, 0.004403507, 0.004109457,
    0.003833913, 0.003575748, 0.003334342, 0.003109075,
    0.002899327, 0.002704348, 0.002523020, 0.002354168,
    0.002196616, 0.002049190, 0.001910960, 0.001781438,
    0.001660110, 0.001546459, 0.001439971, 0.001340042,
    0.001246275, 0.001158471, 0.001076430, 0.0009999493,
    0.0009287358, 0.0008624332, 0.0008007503, 0.0007433960,
    0.0006900786, 0.0006405156, 0.0005945021, 0.0005518646,
    0.0005124290, 0.0004760213, 0.0004424536, 0.0004115117,
    0.0003829814, 0.0003566491, 0.0003323011, 0.0003097586,
    0.0002888871, 0.0002695394, 0.0002515682, 0.0002348261,
    0.0002191710, 0.0002045258, 0.0001908405, 0.0001780654,
    0.0001661505, 0.0001550236, 0.0001446219, 0.0001349098,
    0.0001258520, 0.0001174130, 0.0001095515, 0.0001022245,
    0.00009539445, 0.00008902390, 0.00008307527, 0.00007751269,
    0.00007231304, 0.00006745778, 0.00006292844, 0.00005870652,
    0.00005477028, 0.00005109918, 0.00004767654, 0.00004448567,
    0.00004150994, 0.00003873324, 0.00003614203, 0.00003372352,
    0.00003146487, 0.00002935326, 0.00002737573, 0.00002552433,
    0.00002379376, 0.00002217870, 0.00002067383, 0.00001927226,
    0.00001796640, 0.00001674991, 0.00001561648, 0.00001455977,
    0.00001357387, 0.00001265436, 0.00001179723, 0.00001099844,
    0.00001025398, 0.000009559646, 0.000008912044, 0.000008308358,
    0.000007745769, 0.000007221456, 0.000006732475, 0.000006276423,
    0.000005851304, 0.000005455118, 0.000005085868, 0.000004741466,
    0.000004420236, 0.000004120783, 0.000003841716, 0.000003581652,
    0.000003339127, 0.000003112949, 0.000002902121, 0.000002705645,
    0.000002522525, 0.000002351726, 0.000002192415, 0.000002043902,
    0.000001905497, 0.000001776509, 0.000001656215, 0.000001544022,
    0.000001439440, 0.000001341977, 0.000001251141
};

const float CIE_Y_entries[CIE_samples] = {
    0.000003917000, 0.000004393581, 0.000004929604, 0.000005532136,
    0.000006208245, 0.000006965000, 0.000007813219, 0.000008767336,
    0.000009839844, 0.00001104323, 0.00001239000, 0.00001388641,
    0.00001555728, 0.00001744296, 0.00001958375, 0.00002202000,
    0.00002483965, 0.00002804126, 0.00003153104, 0.00003521521,
    0.00003900000, 0.00004282640, 0.00004691460, 0.00005158960,
    0.00005717640, 0.00006400000, 0.00007234421, 0.00008221224,
    0.00009350816, 0.0001061361, 0.0001200000, 0.0001349840,
    0.0001514920, 0.0001702080, 0.0001918160, 0.0002170000,
    0.0002469067, 0.0002812400, 0.0003185200, 0.0003572667,
    0.0003960000, 0.0004337147, 0.0004730240, 0.0005178760,
    0.0005722187, 0.0006400000, 0.0007245600, 0.0008255000,
    0.0009411600, 0.001069880, 0.001210000, 0.001362091,
    0.001530752, 0.001720368, 0.001935323, 0.002180000,
    0.002454800, 0.002764000, 0.003117800, 0.003526400,
    0.004000000, 0.004546240, 0.005159320, 0.005829280,
    0.006546160, 0.007300000, 0.008086507, 0.008908720,
    0.009767680, 0.01066443, 0.01160000, 0.01257317,
    0.01358272, 0.01462968, 0.01571509, 0.01684000,
    0.01800736, 0.01921448, 0.02045392, 0.02171824,
    0.02300000, 0.02429461, 0.02561024, 0.02695857,
    0.02835125, 0.02980000, 0.03131083, 0.03288368,
    0.03452112, 0.03622571, 0.03800000, 0.03984667,
    0.04176800, 0.04376600, 0.04584267, 0.04800000,
    0.05024368, 0.05257304, 0.05498056, 0.05745872,
    0.06000000, 0.06260197, 0.06527752, 0.06804208,
    0.07091109, 0.07390000, 0.07701600, 0.08026640,
    0.08366680, 0.08723280, 0.09098000, 0.09491755,
    0.09904584, 0.1033674, 0.1078846, 0.1126000,
    0.1175320, 0.1226744, 0.1279928, 0.1334528,
    0.1390200, 0.1446764, 0.1504693, 0.1564619,
    0.1627177, 0.1693000, 0.1762431, 0.1835581,
    0.1912735, 0.1994180, 0.2080200, 0.2171199,
    0.2267345, 0.2368571, 0.2474812, 0.2586000,
    0.2701849, 0.2822939, 0.2950505, 0.3085780,
    0.3230000, 0.3384021, 0.3546858, 0.3716986,
    0.3892875, 0.4073000, 0.4256299, 0.4443096,
    0.4633944, 0.4829395, 0.5030000, 0.5235693,
    0.5445120, 0.5656900, 0.5869653, 0.6082000,
    0.6293456, 0.6503068, 0.6708752, 0.6908424,
    0.7100000, 0.7281852, 0.7454636, 0.7619694,
    0.7778368, 0.7932000, 0.8081104, 0.8224962,
    0.8363068, 0.8494916, 0.8620000, 0.8738108,
    0.8849624, 0.8954936, 0.9054432, 0.9148501,
    0.9237348, 0.9320924, 0.9399226, 0.9472252,
    0.9540000, 0.9602561, 0.9660074, 0.9712606,
    0.9760225, 0.9803000, 0.9840924, 0.9874812,
    0.9903128, 0.9928116, 0.9949501, 0.9967108,
    0.9980983, 0.9991120, 0.9997482, 1.0000000,
    0.9998567, 0.9993046, 0.9983255, 0.9968987,
    0.9950000, 0.9926005, 0.9897426, 0.9864444,
    0.9827241, 0.9786000, 0.9740837, 0.9691712,
    0.9638568, 0.9581349, 0.9520000, 0.9454504,
    0.9384992, 0.9311628, 0.9234576, 0.9154000,
    0.9070064, 0.8982772, 0.8892048, 0.8797816,
    0.8700000, 0.8598613, 0.8493920, 0.8386220,
    0.8275813, 0.8163000, 0.8047947, 0.7930820,
    0.7811920, 0.7691547, 0.7570000, 0.7447541,
    0.7324224, 0.7200036, 0.7074965, 0.6949000,
    0.6822192, 0.6694716, 0.6566744, 0.6438448,
    0.6310000, 0.6181555, 0.6053144, 0.5924756,
    0.5796379, 0.5668000, 0.5539611, 0.5411372,
    0.5283528, 0.5156323, 0.5030000, 0.4904688,
    0.4780304, 0.4656776, 0.4534032, 0.4412000,
    0.4290800, 0.4170360, 0.4050320, 0.3930320,
    0.3810000, 0.3689184, 0.3568272, 0.3447768,
    0.3328176, 0.3210000, 0.3093381, 0.2978504,
    0.2865936, 0.2756245, 0.2650000, 0.2547632,
    0.2448896, 0.2353344, 0.2260528, 0.2170000,
    0.2081616, 0.1995488, 0.1911552, 0.1829744,
    0.1750000, 0.1672235, 0.1596464, 0.1522776,
    0.1451259, 0.1382000, 0.1315003, 0.1250248,
    0.1187792, 0.1127691, 0.1070000, 0.1014762,
    0.09618864, 0.09112296, 0.08626485, 0.08160000,
    0.07712064, 0.07282552, 0.06871008, 0.06476976,
    0.06100000, 0.05739621, 0.05395504, 0.05067376,
    0.04754965, 0.04458000, 0.04175872, 0.03908496,
    0.03656384, 0.03420048, 0.03200000, 0.02996261,
    0.02807664, 0.02632936, 0.02470805, 0.02320000,
    0.02180077, 0.02050112, 0.01928108, 0.01812069,
    0.01700000, 0.01590379, 0.01483718, 0.01381068,
    0.01283478, 0.01192000, 0.01106831, 0.01027339,
    0.009533311, 0.008846157, 0.008210000, 0.007623781,
    0.007085424, 0.006591476, 0.006138485, 0.005723000,
    0.005343059, 0.004995796, 0.004676404, 0.004380075,
    0.004102000, 0.003838453, 0.003589099, 0.003354219,
    0.003134093, 0.002929000, 0.002738139, 0.002559876,
    0.002393244, 0.002237275, 0.002091000, 0.001953587,
    0.001824580, 0.001703580, 0.001590187, 0.001484000,
    0.001384496, 0.001291268, 0.001204092, 0.001122744,
    0.001047000, 0.0009765896, 0.0009111088, 0.0008501332,
    0.0007932384, 0.0007400000, 0.0006900827, 0.0006433100,
    0.0005994960, 0.0005584547, 0.0005200000, 0.0004839136,
    0.0004500528, 0.0004183452, 0.0003887184, 0.0003611000,
    0.0003353835, 0.0003114404, 0.0002891656, 0.0002684539,
    0.0002492000, 0.0002313019, 0.0002146856, 0.0001992884,
    0.0001850475, 0.0001719000, 0.0001597781, 0.0001486044,
    0.0001383016, 0.0001287925, 0.0001200000, 0.0001118595,
    0.0001043224, 0.00009733560, 0.00009084587, 0.00008480000,
    0.00007914667, 0.00007385800, 0.00006891600, 0.00006430267,
    0.00006000000, 0.00005598187, 0.00005222560, 0.00004871840,
    0.00004544747, 0.00004240000, 0.00003956104, 0.00003691512,
    0.00003444868, 0.00003214816, 0.00003000000, 0.00002799125,
    0.00002611356, 0.00002436024, 0.00002272461, 0.00002120000,
    0.00001977855, 0.00001845285, 0.00001721687, 0.00001606459,
    0.00001499000, 0.00001398728, 0.00001305155, 0.00001217818,
    0.00001136254, 0.00001060000, 0.000009885877, 0.000009217304,
    0.000008592362, 0.000008009133, 0.000007465700, 0.000006959567,
    0.000006487995, 0.000006048699, 0.000005639396, 0.000005257800,
    0.000004901771, 0.000004569720, 0.000004260194, 0.000003971739,
    0.000003702900, 0.000003452163, 0.000003218302, 0.000003000300,
    0.000002797139, 0.000002607800, 0.000002431220, 0.000002266531,
    0.000002113013, 0.000001969943, 0.000001836600, 0.000001712230,
    0.000001596228, 0.000001488090, 0.000001387314, 0.000001293400,
    0.000001205820, 0.000001124143, 0.000001048009, 0.0000009770578,
    0.0000009109300, 0.0000008492513, 0.0000007917212, 0.0000007380904,
    0.0000006881098, 0.0000006415300, 0.0000005980895, 0.0000005575746,
    0.0000005198080, 0.0000004846123, 0.0000004518100
};

const float CIE_Z_entries[CIE_samples] = {
    0.0006061000, 0.0006808792, 0.0007651456, 0.0008600124,
    0.0009665928, 0.001086000, 0.001220586, 0.001372729,
    0.001543579, 0.001734286, 0.001946000, 0.002177777,
    0.002435809, 0.002731953, 0.003078064, 0.003486000,
    0.003975227, 0.004540880, 0.005158320, 0.005802907,
    0.006450001, 0.007083216, 0.007745488, 0.008501152,
    0.009414544, 0.01054999, 0.01196580, 0.01365587,
    0.01558805, 0.01773015, 0.02005001, 0.02251136,
    0.02520288, 0.02827972, 0.03189704, 0.03621000,
    0.04143771, 0.04750372, 0.05411988, 0.06099803,
    0.06785001, 0.07448632, 0.08136156, 0.08915364,
    0.09854048, 0.1102000, 0.1246133, 0.1417017,
    0.1613035, 0.1832568, 0.2074000, 0.2336921,
    0.2626114, 0.2947746, 0.3307985, 0.3713000,
    0.4162091, 0.4654642, 0.5196948, 0.5795303,
    0.6456000, 0.7184838, 0.7967133, 0.8778459,
    0.9594390, 1.0390501, 1.1153673, 1.1884971,
    1.2581233, 1.3239296, 1.3856000, 1.4426352,
    1.4948035, 1.5421903, 1.5848807, 1.6229600,
    1.6564048, 1.6852959, 1.7098745, 1.7303821,
    1.7470600, 1.7600446, 1.7696233, 1.7762637,
    1.7804334, 1.7826000, 1.7829682, 1.7816998,
    1.7791982, 1.7758671, 1.7721100, 1.7682589,
    1.7640390, 1.7589438, 1.7524663, 1.7441000,
    1.7335595, 1.7208581, 1.7059369, 1.6887372,
    1.6692000, 1.6475287, 1.6234127, 1.5960223,
    1.5645280, 1.5281000, 1.4861114, 1.4395215,
    1.3898799, 1.3387362, 1.2876400, 1.2374223,
    1.1878243, 1.1387611, 1.0901480, 1.0419000,
    0.9941976, 0.9473473, 0.9014531, 0.8566193,
    0.8129501, 0.7705173, 0.7294448, 0.6899136,
    0.6521049, 0.6162000, 0.5823286, 0.5504162,
    0.5203376, 0.4919673, 0.4651800, 0.4399246,
    0.4161836, 0.3938822, 0.3729459, 0.3533000,
    0.3348578, 0.3175521, 0.3013375, 0.2861686,
    0.2720000, 0.2588171, 0.2464838, 0.2347718,
    0.2234533, 0.2123000, 0.2011692, 0.1901196,
    0.1792254, 0.1685608, 0.1582000, 0.1481383,
    0.1383758, 0.1289942, 0.1200751, 0.1117000,
    0.1039048, 0.09666748, 0.08998272, 0.08384531,
    0.07824999, 0.07320899, 0.06867816, 0.06456784,
    0.06078835, 0.05725001, 0.05390435, 0.05074664,
    0.04775276, 0.04489859, 0.04216000, 0.03950728,
    0.03693564, 0.03445836, 0.03208872, 0.02984000,
    0.02771181, 0.02569444, 0.02378716, 0.02198925,
    0.02030000, 0.01871805, 0.01724036, 0.01586364,
    0.01458461, 0.01340000, 0.01230723, 0.01130188,
    0.01037792, 0.009529306, 0.008749999, 0.008035200,
    0.007381600, 0.006785400, 0.006242800, 0.005749999,
    0.005303600, 0.004899800, 0.004534200, 0.004202400,
    0.003900000, 0.003623200, 0.003370600, 0.003141400,
    0.002934800, 0.002749999, 0.002585200, 0.002438600,
    0.002309400, 0.002196800, 0.002100000, 0.002017733,
    0.001948200, 0.001889800, 0.001840933, 0.001800000,
    0.001766267, 0.001737800, 0.001711200, 0.001683067,
    0.001650001, 0.001610133, 0.001564400, 0.001513600,
    0.001458533, 0.001400000, 0.001336667, 0.001270000,
    0.001205000, 0.001146667, 0.001100000, 0.001068800,
    0.001049400, 0.001035600, 0.001021200, 0.001000000,
    0.0009686400, 0.0009299200, 0.0008868800, 0.0008425600,
    0.0008000000, 0.0007609600, 0.0007236800, 0.0006859200,
    0.0006454400, 0.0006000000, 0.0005478667, 0.0004916000,
    0.0004354000, 0.0003834667, 0.0003400000, 0.0003072533,
    0.0002831600, 0.0002654400, 0.0002518133, 0.0002400000,
    0.0002295467, 0.0002206400, 0.0002119600, 0.0002021867,
    0.0001900000, 0.0001742133, 0.0001556400, 0.0001359600,
    0.0001168533, 0.0001000000, 0.00008613333, 0.00007460000,
    0.00006500000, 0.00005693333, 0.00004999999, 0.00004416000,
    0.00003948000, 0.00003572000, 0.00003264000, 0.00003000000,
    0.00002765333, 0.00002556000, 0.00002364000, 0.00002181333,
    0.00002000000, 0.00001813333, 0.00001620000, 0.00001420000,
    0.00001213333, 0.00001000000, 0.000007733333, 0.000005400000,
    0.000003200000, 0.000001333333, 0.000000000000, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0, 0.0,
    0.0, 0.0, 0.0
};

const float CIE_D65_entries[CIE_samples] = {
    46.6383, 47.1834, 47.7285, 48.2735,
    48.8186, 49.3637, 49.9088, 50.4539,
    50.9989, 51.544,  52.0891, 51.8777,
    51.6664, 51.455,  51.2437, 51.0323,
    50.8209, 50.6096, 50.3982, 50.1869,
    49.9755, 50.4428, 50.91,   51.3773,
    51.8446, 52.3118, 52.7791, 53.2464,
    53.7137, 54.1809, 54.6482, 57.4589,
    60.2695, 63.0802, 65.8909, 68.7015,
    71.5122, 74.3229, 77.1336, 79.9442,
    82.7549, 83.628,  84.5011, 85.3742,
    86.2473, 87.1204, 87.9936, 88.8667,
    89.7398, 90.6129, 91.486,  91.6806,
    91.8752, 92.0697, 92.2643, 92.4589,
    92.6535, 92.8481, 93.0426, 93.2372,
    93.4318, 92.7568, 92.0819, 91.4069,
    90.732,  90.057,  89.3821, 88.7071,
    88.0322, 87.3572, 86.6823, 88.5006,
    90.3188, 92.1371, 93.9554, 95.7736,
    97.5919, 99.4102, 101.228, 103.047,
    104.865, 106.079, 107.294, 108.508,
    109.722, 110.936, 112.151, 113.365,
    114.579, 115.794, 117.008, 117.088,
    117.169, 117.249, 117.33,  117.41,
    117.49,  117.571, 117.651, 117.732,
    117.812, 117.517, 117.222, 116.927,
    116.632, 116.336, 116.041, 115.746,
    115.451, 115.156, 114.861, 114.967,
    115.073, 115.18,  115.286, 115.392,
    115.498, 115.604, 115.711, 115.817,
    115.923, 115.212, 114.501, 113.789,
    113.078, 112.367, 111.656, 110.945,
    110.233, 109.522, 108.811, 108.865,
    108.92,  108.974, 109.028, 109.082,
    109.137, 109.191, 109.245, 109.3,
    109.354, 109.199, 109.044, 108.888,
    108.733, 108.578, 108.423, 108.268,
    108.112, 107.957, 107.802, 107.501,
    107.2,   106.898, 106.597, 106.296,
    105.995, 105.694, 105.392, 105.091,
    104.79,  105.08,  105.37,  105.66,
    105.95,  106.239, 106.529, 106.819,
    107.109, 107.399, 107.689, 107.361,
    107.032, 106.704, 106.375, 106.047,
    105.719, 105.39,  105.062, 104.733,
    104.405, 104.369, 104.333, 104.297,
    104.261, 104.225, 104.19,  104.154,
    104.118, 104.082, 104.046, 103.641,
    103.237, 102.832, 102.428, 102.023,
    101.618, 101.214, 100.809, 100.405,
    100,     99.6334, 99.2668, 98.9003,
    98.5337, 98.1671, 97.8005, 97.4339,
    97.0674, 96.7008, 96.3342, 96.2796,
    96.225,  96.1703, 96.1157, 96.0611,
    96.0065, 95.9519, 95.8972, 95.8426,
    95.788,  95.0778, 94.3675, 93.6573,
    92.947,  92.2368, 91.5266, 90.8163,
    90.1061, 89.3958, 88.6856, 88.8177,
    88.9497, 89.0818, 89.2138, 89.3459,
    89.478,  89.61,   89.7421, 89.8741,
    90.0062, 89.9655, 89.9248, 89.8841,
    89.8434, 89.8026, 89.7619, 89.7212,
    89.6805, 89.6398, 89.5991, 89.4091,
    89.219,  89.029,  88.8389, 88.6489,
    88.4589, 88.2688, 88.0788, 87.8887,
    87.6987, 87.2577, 86.8167, 86.3757,
    85.9347, 85.4936, 85.0526, 84.6116,
    84.1706, 83.7296, 83.2886, 83.3297,
    83.3707, 83.4118, 83.4528, 83.4939,
    83.535,  83.576,  83.6171, 83.6581,
    83.6992, 83.332,  82.9647, 82.5975,
    82.2302, 81.863,  81.4958, 81.1285,
    80.7613, 80.394,  80.0268, 80.0456,
    80.0644, 80.0831, 80.1019, 80.1207,
    80.1395, 80.1583, 80.177,  80.1958,
    80.2146, 80.4209, 80.6272, 80.8336,
    81.0399, 81.2462, 81.4525, 81.6588,
    81.8652, 82.0715, 82.2778, 81.8784,
    81.4791, 81.0797, 80.6804, 80.281,
    79.8816, 79.4823, 79.0829, 78.6836,
    78.2842, 77.4279, 76.5716, 75.7153,
    74.859,  74.0027, 73.1465, 72.2902,
    71.4339, 70.5776, 69.7213, 69.9101,
    70.0989, 70.2876, 70.4764, 70.6652,
    70.854,  71.0428, 71.2315, 71.4203,
    71.6091, 71.8831, 72.1571, 72.4311,
    72.7051, 72.979,  73.253,  73.527,
    73.801,  74.075,  74.349,  73.0745,
    71.8,    70.5255, 69.251,  67.9765,
    66.702,  65.4275, 64.153,  62.8785,
    61.604,  62.4322, 63.2603, 64.0885,
    64.9166, 65.7448, 66.573,  67.4011,
    68.2293, 69.0574, 69.8856, 70.4057,
    70.9259, 71.446,  71.9662, 72.4863,
    73.0064, 73.5266, 74.0467, 74.5669,
    75.087,  73.9376, 72.7881, 71.6387,
    70.4893, 69.3398, 68.1904, 67.041,
    65.8916, 64.7421, 63.5927, 61.8752,
    60.1578, 58.4403, 56.7229, 55.0054,
    53.288,  51.5705, 49.8531, 48.1356,
    46.4182, 48.4569, 50.4956, 52.5344,
    54.5731, 56.6118, 58.6505, 60.6892,
    62.728,  64.7667, 66.8054, 66.4631,
    66.1209, 65.7786, 65.4364, 65.0941,
    64.7518, 64.4096, 64.0673, 63.7251,
    63.3828, 63.4749, 63.567,  63.6592,
    63.7513, 63.8434, 63.9355, 64.0276,
    64.1198, 64.2119, 64.304,  63.8188,
    63.3336, 62.8484, 62.3632, 61.8779,
    61.3927, 60.9075, 60.4223, 59.9371,
    59.4519, 58.7026, 57.9533, 57.204,
    56.4547, 55.7054, 54.9562, 54.2069,
    53.4576, 52.7083, 51.959,  52.5072,
    53.0553, 53.6035, 54.1516, 54.6998,
    55.248,  55.7961, 56.3443, 56.8924,
    57.4406, 57.7278, 58.015,  58.3022,
    58.5894, 58.8765, 59.1637, 59.4509,
    59.7381, 60.0253, 60.3125
};