axmol/tests/unit-tests/Source/core/math/FastRNGTests.cpp

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 Copyright (c) 2019-present Axmol Engine contributors (see AUTHORS.md).

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#include <doctest.h>
#include <float.h>
#include "math/FastRNG.h"


TEST_SUITE("math/FastRNG") {
    TEST_CASE("next") {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(1695105466, rng.next());
        CHECK_EQ(1423115009, rng.next());
        CHECK_EQ(634581793, rng.next());

        auto rng2 = ax::FastRNG();
        rng2.seed(2);

        CHECK_EQ(1086064458, rng2.next());
        CHECK_EQ(2256779072, rng2.next());
        CHECK_EQ(556893360, rng2.next());
    }

    TEST_CASE("nextInt")
    {
        auto rng = ax::FastRNG();
        rng.seed(12);

        CHECK_EQ(30, rng.nextInt<int8_t>(INT8_MIN, INT8_MAX));
        CHECK_EQ(124, rng.nextInt<uint8_t>(0, UINT8_MAX));

        CHECK_EQ(-14353, rng.nextInt<int16_t>(INT16_MIN, INT16_MAX));
        CHECK_EQ(61806, rng.nextInt<uint16_t>(0, UINT16_MAX));

        CHECK_EQ(-1775882703, rng.nextInt<int32_t>(INT32_MIN, INT32_MAX));
        CHECK_EQ(1623340863, rng.nextInt<uint32_t>(0, UINT32_MAX));
    }

    TEST_CASE("nextReal")
    {
        auto rng = ax::FastRNG();
        rng.seed(14);

        CHECK_EQ(doctest::Approx(0.927014), rng.nextReal<float>());
        CHECK_EQ(doctest::Approx(2.02437e+38), rng.nextReal<float>(0, FLT_MAX));
        CHECK_EQ(doctest::Approx(2.79091e+38), rng.nextReal<float>(FLT_MIN, FLT_MAX));

        CHECK_EQ(doctest::Approx(0.845991), rng.nextReal<double>());
        CHECK_EQ(doctest::Approx(1.50478e+308), rng.nextReal<double>(0, DBL_MAX));
        CHECK_EQ(doctest::Approx(9.94378e+307), rng.nextReal<double>(DBL_MIN, DBL_MAX));
    }

    TEST_CASE("range") {
        auto rng = ax::FastRNG();
        rng.seed(12345);

        CHECK_EQ(0, rng.range(0, 1));
        CHECK_EQ(-1, rng.range(-1, 0));
        CHECK_EQ(14, rng.range(10, 20));
        CHECK_EQ(19, rng.range(10, 20));
        CHECK_EQ(-18, rng.range(-20, -10));
        CHECK_EQ(-19, rng.range(-20, -10));

        CHECK_EQ(-704160663, rng.range(-INT_MAX, INT_MAX));
        CHECK_EQ(1299678946, rng.range(-INT_MAX, INT_MAX));
    }

    TEST_CASE("max")
    {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(0, rng.max(1));
        CHECK_EQ(3, rng.max(10));
        CHECK_EQ(317290896, rng.max());
    }


    TEST_CASE("rangeu") {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(0u, rng.rangeu(0u, 1u));
        CHECK_EQ(0u, rng.rangeu(0u, 1u));
        CHECK_EQ(11u, rng.rangeu(10u, 20u));

        CHECK_EQ(1068227752, rng.rangeu(0u, UINT_MAX));
    }

    TEST_CASE("maxu")
    {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(0u, rng.maxu(1));
        CHECK_EQ(3u, rng.maxu(10));
        CHECK_EQ(634581792, rng.maxu());
    }

    TEST_CASE("rangef") {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(doctest::Approx(-0.210655), rng.rangef(-1.0f, 1.0f));
        CHECK_EQ(doctest::Approx(-0.33731), rng.rangef(-1.0f, 1.0f));
        CHECK_EQ(doctest::Approx(11.4775), rng.rangef(10.0f, 20.0f));
        // These overflow
        // CHECK_EQ(doctest::Approx(1.0), rng.rangef(-FLT_MAX, FLT_MAX));
        // CHECK_EQ(doctest::Approx(1.0), rng.rangef(-FLT_MAX, FLT_MAX));
    }


    TEST_CASE("maxf") {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(doctest::Approx(0.394672), rng.maxf(1.0f));
        CHECK_EQ(doctest::Approx(0.331345), rng.maxf(1.0f));
        CHECK_EQ(doctest::Approx(1.4775), rng.maxf(10.0f));
        CHECK_EQ(doctest::Approx(8.46337e+37), rng.maxf(FLT_MAX));
        CHECK_EQ(doctest::Approx(5.67875e+37), rng.maxf(FLT_MAX));
    }

    TEST_CASE("ranged")
    {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(doctest::Approx(-0.210655), rng.ranged(-1.0, 1.0));
        CHECK_EQ(doctest::Approx(-0.7045), rng.ranged(-1.0, 1.0));
        CHECK_EQ(doctest::Approx(11.6688), rng.ranged(10.0, 20.0));
    }

    TEST_CASE("maxd")
    {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(doctest::Approx(0.394672), rng.maxd(1.0f));
        CHECK_EQ(doctest::Approx(0.14775), rng.maxd(1.0f));
        CHECK_EQ(doctest::Approx(1.66884), rng.maxd(10.0f));
        CHECK_EQ(doctest::Approx(1.58118e+308), rng.maxd(DBL_MAX));
        CHECK_EQ(doctest::Approx(1.19643e+308), rng.maxd(DBL_MAX));
    }

    TEST_CASE("float01") {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(doctest::Approx(0.394672), rng.float01());
        CHECK_EQ(doctest::Approx(0.331345), rng.float01());
        CHECK_EQ(doctest::Approx(0.14775), rng.float01());
        CHECK_EQ(doctest::Approx(0.248716), rng.float01());
    }

    TEST_CASE("double01")
    {
        auto rng = ax::FastRNG();
        rng.seed(1);

        CHECK_EQ(doctest::Approx(0.394672), rng.double01());
        CHECK_EQ(doctest::Approx(0.14775), rng.double01());
        CHECK_EQ(doctest::Approx(0.166884), rng.double01());
        CHECK_EQ(doctest::Approx(0.879563), rng.double01());
    }

    TEST_CASE("bool01") {
        auto rng = ax::FastRNG();
        rng.seed(1);

        auto t = 0;
        auto f = 0;
        for (auto i = 0; i < 100; i++) {
            if (rng.bool01()) {
                t++;
            } else {
                f++;
            }
        }

        CHECK_EQ(50, t);
        CHECK_EQ(50, f);
    }
}