Use longs to avoid two's complement failure in approxEqual

diff --git a/src/OpenTK/Math/MathHelper.cs b/src/OpenTK/Math/MathHelper.cs
index a5ecc61..f1effe6 100644 (file)
--- 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);
                }