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Merge pull request #10 from Valmar33/revert-8-revert-7-master

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Revert "Revert "Added HMM_FastInverseSquareRoot function""
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Zak Strange
2016-05-28 13:00:38 -07:00
parent 6c0f340920 557900d1b2
commit fc9adc8ab7
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_Inner(hmm_vec3 A, hmm_vec3 B);
HMMDEF float HMM_SquareRoot(float Float); HMMDEF float HMM_SquareRoot(float Float);
HMMDEF float HMM_LengthSquareRoot(hmm_vec3 A); HMMDEF float HMM_LengthSquareRoot(hmm_vec3 A);
HMMDEF float HMM_FastInverseSquareRoot(float Number);
HMMDEF float HMM_Length(hmm_vec3 A); HMMDEF float HMM_Length(hmm_vec3 A);
HMMDEF float HMM_Power(float Base, int Exponent); HMMDEF float HMM_Power(float Base, int Exponent);
HMMDEF float HMM_Clamp(float Min, float Value, float Max); HMMDEF float HMM_Clamp(float Min, float Value, float Max);
@@ -351,6 +352,24 @@ HMM_LengthSquareRoot(hmm_vec3 A)
return (Result); 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 HINLINE float
HMM_Length(hmm_vec3 A) HMM_Length(hmm_vec3 A)
{ {