From ec69aba0a9afcfe30d56a077a19bbf37305896f5 Mon Sep 17 00:00:00 2001
From: assiduous <assiduous@diligentgraphics.com>
Date: Mon, 29 Jan 2024 15:23:34 -0800
Subject: [PATCH] MathLib: added WrapToRange function

---
 Common/interface/BasicMath.hpp                | 14 ++++++++
 .../src/Common/MathLibTest.cpp                | 34 ++++++++++++++++++-
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/Common/interface/BasicMath.hpp b/Common/interface/BasicMath.hpp
index 736c65f13..8e5125409 100644
--- a/Common/interface/BasicMath.hpp
+++ b/Common/interface/BasicMath.hpp
@@ -2668,6 +2668,20 @@ typename std::enable_if<std::is_enum<T>::value, T>::type ExtractLSB(T& bits)
     return static_cast<T>(ExtractLSB(reinterpret_cast<typename std::underlying_type<T>::type&>(bits)));
 }
 
+/// Wraps Value to the range [Min, Min + Range)
+template <typename T>
+T WrapToRange(T Value, T Min, T Range)
+{
+    VERIFY_EXPR(Range >= 0);
+    if (Range <= 0)
+        return Min;
+
+    T Result = (Value - Min) % Range;
+    if (Result < 0)
+        Result += Range;
+
+    return Result + Min;
+}
 
 inline std::ostream& operator<<(std::ostream& os, const float4& vec)
 {
diff --git a/Tests/DiligentCoreTest/src/Common/MathLibTest.cpp b/Tests/DiligentCoreTest/src/Common/MathLibTest.cpp
index c135b8731..8397a4b7b 100644
--- a/Tests/DiligentCoreTest/src/Common/MathLibTest.cpp
+++ b/Tests/DiligentCoreTest/src/Common/MathLibTest.cpp
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2019-2023 Diligent Graphics LLC
+ *  Copyright 2019-2024 Diligent Graphics LLC
  *  Copyright 2015-2019 Egor Yusov
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
@@ -2292,6 +2292,38 @@ TEST(Common_BasicMath, VectorAll)
     EXPECT_FALSE(all(double4{1, 1, 1, 0}));
 }
 
+
+TEST(Common_BasicMath, Wrap)
+{
+    EXPECT_EQ(WrapToRange(10, 1, 0), 1);
+    EXPECT_EQ(WrapToRange(10, 1, 1), 1);
+    EXPECT_EQ(WrapToRange(-10, 1, 0), 1);
+    EXPECT_EQ(WrapToRange(-10, 1, 1), 1);
+
+    EXPECT_EQ(WrapToRange(0, 200, 10), 200);
+    EXPECT_EQ(WrapToRange(1, 200, 10), 201);
+    EXPECT_EQ(WrapToRange(9, 200, 10), 209);
+    EXPECT_EQ(WrapToRange(10, 200, 10), 200);
+
+    EXPECT_EQ(WrapToRange(-1, 200, 10), 209);
+    EXPECT_EQ(WrapToRange(-9, 200, 10), 201);
+    EXPECT_EQ(WrapToRange(-10, 200, 10), 200);
+
+    for (int Range : {1, 2, 7, 8, 9, 10, 15, 16, 17})
+    {
+        int Min = -Range / 2;
+        for (int i = -2; i <= 2; ++i)
+        {
+            for (int Ref = Min; Ref < Min + Range; ++Ref)
+            {
+                int Value = i * Range + Ref;
+                EXPECT_EQ(WrapToRange(Value, Min, Range), Ref) << Value << " " << Min << " " << Range;
+            }
+        }
+    }
+}
+
+
 TEST(Common_AdvancedMath, IsPointInsideTriangleF)
 {
     {