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Merge pull request #7 from Valmar33/master

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Added HMM_FastInverseSquareRoot function
This commit is contained in:
Zak Strange
2016-05-28 11:08:44 -07:00
parent ceaf77f9d3 116e3bb41b
commit 73afb729d5
1 changed files with 19 additions and 0 deletions
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19
HandmadeMath.h
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@@ -223,6 +223,7 @@ HMMDEF float HMM_ToRadians(float Degrees);
HMMDEF float HMM_Inner(hmm_vec3 A, hmm_vec3 B);
HMMDEF float HMM_SquareRoot(float Float);
HMMDEF float HMM_LengthSquareRoot(hmm_vec3 A);
HMMDEF float HMM_FastInverseSquareRoot(float Number);
HMMDEF float HMM_Length(hmm_vec3 A);
HMMDEF float HMM_Power(float Base, int Exponent);
HMMDEF float HMM_Clamp(float Min, float Value, float Max);
@@ -351,6 +352,24 @@ HMM_LengthSquareRoot(hmm_vec3 A)
return (Result);
}
HINLINE float
HMM_FastInverseSquareRoot(float Number)
{
long i;
float x2, y;
const float threehalfs = 1.5f;
x2 = Number * 0.5f;
y = Number;
i = * ( long * ) &y; // evil floating point bit level hacking
i = 0x5f3759df - ( i >> 1 ); // what the fuck?
y = * ( float * ) &i;
y = y * ( threehalfs - ( x2 * y * y ) );
return ( y );
}
HINLINE float
HMM_Length(hmm_vec3 A)
{