Linear Interpolation Optimization For Sign-ness
<p>In a tight loop, I am doing a linear interpolation between two floating point values. However, the only necessary part of the result is the sign (whether the result is negative or positive). I'm doing a typical lerp operation right now, f way between a and b.</p>

<pre><code>a + f * (b - a);
</code></pre>

<p>Is there something more efficient considering I just need to know the resulting sign and not the actual lerped value?</p>

<p>Edit: 'f' is a set of fixed distances along the interpolation, which are known beforehand.</p>