¹This almost never happens.
float Q_rsqrt( 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 ) ); // 1st iteration
// y = y * ( threehalfs - ( x2 * y * y ) ); // 2nd iteration, this can be removed
return y;
}https://github.com/id-Software/Quake-III-arena/blob/master/c...
Carmack (and id software games) are legendary in terms of their high-performance. And given the source code of these games... the source code filled with raw assembly language and other such tricks like I posted above... the source code is nearly impossible to read for the "typical" programmer.
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This is absolutely not a company (or engineer) who did things "simply". He did things in a extremely difficult, high-performance first engineering mindset.
I dare say that John Carmack's practice is closer to "premature optimization", built around abusing incredibly low-level tricks to improve the performance of their various video games... and strategically choosing parts of the video-game simulation that people would prefer high-performance over accuracy. (IIRC: the Fast Inverse Square Root algorithm above is only ~4 digits or 12-bits worth of accuracy).
This was a programmer (or at least, programming team) that at a high level, decided that 12ish-bits of accuracy (out of 23-maximum bits of precision) was enough for their purposes in the vast majority of their code. And then used that slight performance increase to have a smoother-feeling game than their competition.
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IIRC, John Carmack is a legendary programmer in terms of low-level 3d details. He is a good programmer, but his style is the complete opposite of what you're calling it.