本帖最后由 liang7143 于 2012-7-14 15:55 编辑
呵呵，给LZ看一看一个更晕的函数
求平方根的倒数，等同于1/sqrt(x)
- float InvSqrt(float x)
- {
- float xhalf = 0.5f*x;
- int i = *(int*)&x; // get bits for floating value
- i = 0x5f3759df - (i>>1); // gives initial guess
- x = *(float*)&i; // convert bits back to float
- x = x*(1.5f-xhalf*x*x); // Newton step, repeating increases accuracy
- return x;
- }
详细资料可以看附件
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