Carmack在QUAKE3中使用的计算平方根的函数

//

// Carmack在QUAKE3中使用的计算平方根的函数

//

float CarmSqrt(float x){

union{

int intPart;

float floatPart;

} convertor;

union{

int intPart;

float floatPart;

} convertor2;

convertor.floatPart = x;

convertor2.floatPart = x;

convertor.intPart = 0x1FBCF800 + (convertor.intPart >> );

convertor2.intPart = 0x5f3759df - (convertor2.intPart >> );

return 0.5f*(convertor.floatPart + (x * convertor2.floatPart));

}