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Optimize Math.NearEqual

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This commit is contained in:
Wojtek Figat
2021-11-23 23:17:05 +01:00
parent 4322563eed
commit a9c56caf84
2 changed files with 22 additions and 51 deletions
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47
Source/Engine/Core/Math/Math.h
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@@ -419,7 +419,7 @@ namespace Math
return (T)0;
return Saturate((value - a) / (b - a));
}
// Performs smooth (cubic Hermite) interpolation between 0 and 1
// @param amount Value between 0 and 1 indicating interpolation amount
static float SmoothStep(float amount)
@@ -480,44 +480,16 @@ namespace Math
}
/// <summary>
/// Checks if a and b are not even almost equal, taking into account the magnitude of floating point numbers
/// </summary>
/// <param name="a">The left value to compare</param>
/// <param name="b">The right value to compare</param>
/// <returns>False if a almost equal to b, otherwise true</returns>
static bool NotNearEqual(float a, float b)
{
// Check if the numbers are really close - needed when comparing numbers near zero
if (IsZero(a - b))
return false;
// Original from Bruce Dawson: http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
const int32 aInt = *(int32*)&a;
const int32 bInt = *(int32*)&b;
// Different signs means they do not match
if (aInt < 0 != bInt < 0)
return true;
// Find the difference in ULPs
const int ulp = Abs(aInt - bInt);
// Choose of maxUlp = 4
// according to http://code.google.com/p/googletest/source/browse/trunk/include/gtest/internal/gtest-internal.h
const int maxUlp = 4;
return ulp > maxUlp;
}
/// <summary>
/// Checks if a and b are almost equals, taking into account the magnitude of floating point numbers
/// Checks if a and b are almost equals, taking into account the magnitude of floating point numbers.
/// </summary>
/// <remarks>The code is using the technique described by Bruce Dawson in <a href="http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/">Comparing Floating point numbers 2012 edition</a>.</remarks>
/// <param name="a">The left value to compare</param>
/// <param name="b">The right value to compare</param>
/// <returns>True if a almost equal to b, otherwise false</returns>
static bool NearEqual(float a, float b)
{
// Check if the numbers are really close - needed when comparing numbers near zero
if (IsZero(a - b))
if (Abs(a) < ZeroTolerance)
return true;
// Original from Bruce Dawson: http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
@@ -537,6 +509,17 @@ namespace Math
return ulp <= maxUlp;
}
/// <summary>
/// Checks if a and b are not even almost equal, taking into account the magnitude of floating point numbers
/// </summary>
/// <param name="a">The left value to compare</param>
/// <param name="b">The right value to compare</param>
/// <returns>False if a almost equal to b, otherwise true</returns>
static FORCE_INLINE bool NotNearEqual(float a, float b)
{
return !NearEqual(a, b);
}
/// <summary>
/// Checks if a and b are almost equals within the given epsilon value.
/// </summary>