From 17ecdb1cc718f103c58b4abdcb9bfd5c630c77ec Mon Sep 17 00:00:00 2001
From: ikpil <ikpil@naver.com>
Date: Thu, 30 May 2024 22:53:01 +0900
Subject: [PATCH] added RcMath.Lerp()

---
 src/DotRecast.Core/RcMath.cs           |  6 ++++
 test/DotRecast.Core.Test/RcMathTest.cs | 38 ++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 test/DotRecast.Core.Test/RcMathTest.cs

diff --git a/src/DotRecast.Core/RcMath.cs b/src/DotRecast.Core/RcMath.cs
index 0b407da..b981bd1 100644
--- a/src/DotRecast.Core/RcMath.cs
+++ b/src/DotRecast.Core/RcMath.cs
@@ -29,5 +29,11 @@ namespace DotRecast.Core
         {
             return f * f;
         }
+        
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static float Lerp(float value1, float value2, float amount)
+        {
+            return (value1 * (1.0f - amount)) + (value2 * amount);
+        }
     }
 }
\ No newline at end of file
diff --git a/test/DotRecast.Core.Test/RcMathTest.cs b/test/DotRecast.Core.Test/RcMathTest.cs
new file mode 100644
index 0000000..9bdda89
--- /dev/null
+++ b/test/DotRecast.Core.Test/RcMathTest.cs
@@ -0,0 +1,38 @@
+using System;
+using NUnit.Framework;
+
+namespace DotRecast.Core.Test;
+
+public class RcMathTest
+{
+    [Test]
+    public void TestSqr()
+    {
+        Assert.That(RcMath.Sqr(0), Is.EqualTo(0));
+        Assert.That(RcMath.Sqr(5), Is.EqualTo(25));
+        Assert.That(RcMath.Sqr(-5), Is.EqualTo(25));
+        Assert.That(RcMath.Sqr(float.PositiveInfinity), Is.EqualTo(float.PositiveInfinity));
+        Assert.That(RcMath.Sqr(float.NegativeInfinity), Is.EqualTo(float.PositiveInfinity));
+        Assert.That(RcMath.Sqr(float.NaN), Is.EqualTo(float.NaN));
+    }
+
+    [Test]
+    public void TestLerp()
+    {
+        //
+        Assert.That(RcMath.Lerp(-10, 10, 2f), Is.EqualTo(30));
+        Assert.That(RcMath.Lerp(-10, 10, 1f), Is.EqualTo(10));
+        Assert.That(RcMath.Lerp(-10, 10, 0.5f), Is.EqualTo(0));
+        Assert.That(RcMath.Lerp(-10, 10, 0.25f), Is.EqualTo(-5));
+        Assert.That(RcMath.Lerp(-10, 10, 0), Is.EqualTo(-10));
+        Assert.That(RcMath.Lerp(-10, 10, -0.5f), Is.EqualTo(-20));
+        Assert.That(RcMath.Lerp(-10, 10, -1f), Is.EqualTo(-30));
+
+        //
+        Assert.That(RcMath.Lerp(10, 10, 0.5f), Is.EqualTo(10));
+        Assert.That(RcMath.Lerp(10, 10, 0.8f), Is.EqualTo(10));
+
+        //
+        Assert.That(RcMath.Lerp(10, -10, 0.75f), Is.EqualTo(-5));
+    }
+}
\ No newline at end of file