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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 (T)0;
return Saturate((value - a) / (b - a)); return Saturate((value - a) / (b - a));
} }
// Performs smooth (cubic Hermite) interpolation between 0 and 1 // Performs smooth (cubic Hermite) interpolation between 0 and 1
// @param amount Value between 0 and 1 indicating interpolation amount // @param amount Value between 0 and 1 indicating interpolation amount
static float SmoothStep(float amount) static float SmoothStep(float amount)
@@ -480,44 +480,16 @@ namespace Math
} }
/// <summary> /// <summary>
/// Checks if a and b are not even almost equal, 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>
/// <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
/// </summary> /// </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="a">The left value to compare</param>
/// <param name="b">The right value to compare</param> /// <param name="b">The right value to compare</param>
/// <returns>True if a almost equal to b, otherwise false</returns> /// <returns>True if a almost equal to b, otherwise false</returns>
static bool NearEqual(float a, float b) static bool NearEqual(float a, float b)
{ {
// Check if the numbers are really close - needed when comparing numbers near zero // Check if the numbers are really close - needed when comparing numbers near zero
if (IsZero(a - b)) if (Abs(a) < ZeroTolerance)
return true; return true;
// Original from Bruce Dawson: http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/ // 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; 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> /// <summary>
/// Checks if a and b are almost equals within the given epsilon value. /// Checks if a and b are almost equals within the given epsilon value.
/// </summary> /// </summary>

26
Source/Engine/Core/Math/Mathf.cs
View File

@@ -586,8 +586,7 @@ namespace FlaxEngine
/// <param name="maxSpeed">The maximum speed.</param> /// <param name="maxSpeed">The maximum speed.</param>
/// <param name="deltaTime">The delta time (in seconds) since last update.</param> /// <param name="deltaTime">The delta time (in seconds) since last update.</param>
/// <returns>The smoothed value.</returns> /// <returns>The smoothed value.</returns>
public static float SmoothDamp(float current, float target, ref float currentVelocity, float smoothTime, [DefaultValue("float.PositiveInfinity")] public static float SmoothDamp(float current, float target, ref float currentVelocity, float smoothTime, [DefaultValue("float.PositiveInfinity")] float maxSpeed, [DefaultValue("Time.DeltaTime")] float deltaTime)
float maxSpeed, [DefaultValue("Time.DeltaTime")] float deltaTime)
{ {
smoothTime = Max(0.0001f, smoothTime); smoothTime = Max(0.0001f, smoothTime);
float a = 2f / smoothTime; float a = 2f / smoothTime;
@@ -646,8 +645,7 @@ namespace FlaxEngine
/// <param name="maxSpeed">The maximum speed.</param> /// <param name="maxSpeed">The maximum speed.</param>
/// <param name="deltaTime">The delta time (in seconds) since last update.</param> /// <param name="deltaTime">The delta time (in seconds) since last update.</param>
/// <returns>The smoothed value.</returns> /// <returns>The smoothed value.</returns>
public static float SmoothDampAngle(float current, float target, ref float currentVelocity, float smoothTime, [DefaultValue("float.PositiveInfinity")] public static float SmoothDampAngle(float current, float target, ref float currentVelocity, float smoothTime, [DefaultValue("float.PositiveInfinity")] float maxSpeed, [DefaultValue("Time.DeltaTime")] float deltaTime)
float maxSpeed, [DefaultValue("Time.DeltaTime")] float deltaTime)
{ {
target = current + DeltaAngle(current, target); target = current + DeltaAngle(current, target);
return SmoothDamp(current, target, ref currentVelocity, smoothTime, maxSpeed, deltaTime); return SmoothDamp(current, target, ref currentVelocity, smoothTime, maxSpeed, deltaTime);
@@ -905,26 +903,16 @@ namespace FlaxEngine
} }
/// <summary> /// <summary>
/// Checks if a and b are almost equals, taking into account the magnitude of floating point numbers (unlike /// Checks if a and b are almost equals, taking into account the magnitude of floating point numbers (unlike <see cref="WithinEpsilon" /> method).
/// <see cref="WithinEpsilon" /> method). See Remarks.
/// See remarks.
/// </summary> /// </summary>
/// <param name="a">The left value to compare.</param> /// <param name="a">The left value to compare.</param>
/// <param name="b">The right value to compare.</param> /// <param name="b">The right value to compare.</param>
/// <returns><c>true</c> if a almost equal to b, <c>false</c> otherwise</returns> /// <returns><c>true</c> if a almost equal to b, <c>false</c> otherwise</returns>
/// <remarks> /// <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>
/// 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>
public static unsafe bool NearEqual(float a, float b) public static unsafe bool NearEqual(float a, float b)
{ {
// Check if the numbers are really close -- needed // Check if the numbers are really close -- needed when comparing numbers near zero.
// when comparing numbers near zero. if (Math.Abs(a - b) < Epsilon)
if (IsZero(a - b))
return true; return true;
// Original from Bruce Dawson: http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/ // Original from Bruce Dawson: http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/
@@ -973,7 +961,7 @@ namespace FlaxEngine
/// <returns><c>true</c> if the specified value is close to one (1.0f); otherwise, <c>false</c>.</returns> /// <returns><c>true</c> if the specified value is close to one (1.0f); otherwise, <c>false</c>.</returns>
public static bool IsOne(float a) public static bool IsOne(float a)
{ {
return IsZero(a - 1.0f); return Math.Abs(a - 1.0f) < Epsilon;
} }
/// <summary> /// <summary>