Halton sequence added to AzCore/Math/Random.h with unit tests. This work is in support of ATOM-13988 for generating sub-pixel camera offsets for TAA jitter.

Code/Framework/AzCore/Tests/Math/RandomTests.cpp

@@ -0,0 +1,74 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include <AzCore/Math/Random.h>
+#include <AzCore/UnitTest/TestTypes.h>
+
+using namespace AZ;
+
+namespace UnitTest
+{
+    TEST(MATH_Random, GetHaltonNumber)
+    {
+        EXPECT_FLOAT_EQ(0.5, GetHaltonNumber(1, 2));
+        EXPECT_FLOAT_EQ(898.0f / 2187.0f, GetHaltonNumber(1234, 3));
+        EXPECT_FLOAT_EQ(5981.0f / 15625.0f, GetHaltonNumber(4321, 5));
+    }
+
+    TEST(MATH_Random, HaltonSequence)
+    {
+        HaltonSequence<3> sequence({ 2, 3, 5 });
+        auto regularSequence = sequence.GetHaltonSequence<5>();
+
+        EXPECT_FLOAT_EQ(1.0f / 2.0f, regularSequence[0][0]);
+        EXPECT_FLOAT_EQ(1.0f / 3.0f, regularSequence[0][1]);
+        EXPECT_FLOAT_EQ(1.0f / 5.0f, regularSequence[0][2]);
+
+        EXPECT_FLOAT_EQ(1.0f / 4.0f, regularSequence[1][0]);
+        EXPECT_FLOAT_EQ(2.0f / 3.0f, regularSequence[1][1]);
+        EXPECT_FLOAT_EQ(2.0f / 5.0f, regularSequence[1][2]);
+
+        EXPECT_FLOAT_EQ(3.0f / 4.0f, regularSequence[2][0]);
+        EXPECT_FLOAT_EQ(1.0f / 9.0f, regularSequence[2][1]);
+        EXPECT_FLOAT_EQ(3.0f / 5.0f, regularSequence[2][2]);
+
+        EXPECT_FLOAT_EQ(1.0f / 8.0f, regularSequence[3][0]);
+        EXPECT_FLOAT_EQ(4.0f / 9.0f, regularSequence[3][1]);
+        EXPECT_FLOAT_EQ(4.0f / 5.0f, regularSequence[3][2]);
+
+        EXPECT_FLOAT_EQ(5.0f / 8.0f, regularSequence[4][0]);
+        EXPECT_FLOAT_EQ(7.0f / 9.0f, regularSequence[4][1]);
+        EXPECT_FLOAT_EQ(1.0f / 25.0f, regularSequence[4][2]);
+
+        sequence.SetOffsets({ 1, 2, 3 });
+        auto offsetSequence = sequence.GetHaltonSequence<2>();
+
+        EXPECT_FLOAT_EQ(1.0f / 4.0f, offsetSequence[0][0]);
+        EXPECT_FLOAT_EQ(1.0f / 9.0f, offsetSequence[0][1]);
+        EXPECT_FLOAT_EQ(4.0f / 5.0f, offsetSequence[0][2]);
+
+        EXPECT_FLOAT_EQ(3.0f / 4.0f, offsetSequence[1][0]);
+        EXPECT_FLOAT_EQ(4.0f / 9.0f, offsetSequence[1][1]);
+        EXPECT_FLOAT_EQ(1.0f / 25.0f, offsetSequence[1][2]);
+        
+        sequence.SetIncrements({ 1, 2, 3 });
+        auto incrementedSequence = sequence.GetHaltonSequence<2>();
+        
+        EXPECT_FLOAT_EQ(1.0f / 4.0f, incrementedSequence[0][0]);
+        EXPECT_FLOAT_EQ(1.0f / 9.0f, incrementedSequence[0][1]);
+        EXPECT_FLOAT_EQ(4.0f / 5.0f, incrementedSequence[0][2]);
+
+        EXPECT_FLOAT_EQ(3.0f / 4.0f, incrementedSequence[1][0]);
+        EXPECT_FLOAT_EQ(7.0f / 9.0f, incrementedSequence[1][1]);
+        EXPECT_FLOAT_EQ(11.0f / 25.0f, incrementedSequence[1][2]);
+    }
+}

Code/Framework/AzCore/Tests/azcoretests_files.cmake

@@ -152,6 +152,7 @@ set(FILES
     Math/PlaneTests.cpp
     Math/QuaternionPerformanceTests.cpp
     Math/QuaternionTests.cpp
+    Math/RandomTests.cpp
     Math/ShapeIntersectionPerformanceTests.cpp
     Math/ShapeIntersectionTests.cpp
     Math/SfmtTests.cpp