Line of sight

[na_th_an]

A quick speed test of

answer=distance (i,j) against
answer=iSqrt(i*i+j*j) shows:

• distance 8.98 seconds
  iSqrt 50.1 seconds
  

This is definitely faster, if you're willing to accept the greater inaccuracy. (you probably are).

By the by - standard floating point square root:

my fSQRt function: 44 minutes (2625.14 seconds)
SQR - 122 minutes. (7336.86 seconds)

Shows how awful that ROM SQR routine really is...

Impressive results. I have a couple of uses for your fSQRt function - thanks for sharing