From 3e38074a9f49fae439e9e8ce84d3f5da537d88c7 Mon Sep 17 00:00:00 2001
From: varon <varon@users.noreply.github.com>
Date: Sun, 19 Mar 2017 15:56:16 +0200
Subject: [PATCH] Use longs to avoid two's complement failure in approxEqual

---
 src/OpenTK/Math/MathHelper.cs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/OpenTK/Math/MathHelper.cs b/src/OpenTK/Math/MathHelper.cs
index a5ecc61c..f1effe6e 100644
--- a/src/OpenTK/Math/MathHelper.cs
+++ b/src/OpenTK/Math/MathHelper.cs
@@ -341,15 +341,16 @@ namespace OpenTK
 		/// <param name="maxDeltaBits">the number of floating point bits to check</param>
 		/// <returns></returns>
 		public static bool ApproximatelyEqual(float a, float b, int maxDeltaBits) {
-			int aInt = FloatToInt32Bits(a);
+			// we use longs here, otherwise we run into a two's complement problem, causing this to fail with -2 and 2.0
+			long aInt = FloatToInt32Bits(a);
 			if (aInt < 0)
 				aInt = Int32.MinValue - aInt;
 
-			int bInt = FloatToInt32Bits(b);
+			long bInt = FloatToInt32Bits(b);
 			if (bInt < 0)
 				bInt = Int32.MinValue - bInt;
 
-			int intDiff = Math.Abs(aInt - bInt);
+			long intDiff = Math.Abs(aInt - bInt);
 			return intDiff <= (1 << maxDeltaBits);
 		}