Created
December 30, 2020 09:45
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Inverse Square Root by Greg Walsh
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| float invSqrt(float x) | |
| { | |
| union { | |
| float x; | |
| int i; | |
| } u; | |
| float xhalf = 0.5f * x; | |
| u.x = x; | |
| u.i = 0x5f3759df - (u.i >> 1); | |
| u.x = u.x * (1.5f - xhalf * u.x * u.x); | |
| return u.x; | |
| } |
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This is a more readable version of the famous invSqrt from idTech 3 (Quake 3 engine), likely created by Greg Walsh.