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Checking to see if a point lies within a square requires two subtractions and two comparisons. Proper vector distance calculations for radial inclusion usually require 3 multiplies an addition a subtraction and a comparison.I haven't looked at the code for this lately, but it does still do a vector distance calc, doesn't it?
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the actual code does box-checking in AICheckCloseArrgo as far as i know, thus abs(x1-x2)<dist && abs(y1-y2) <dist.
In the Terrain code, it is exact-distance calc. However this is little overhead, as :
- those in the corner (pass square test, fail exact test) are not checked against lately in AICheckCloseArrgo), thus time saved in the end
- event though caching uses cpu (about 3% in very heavy zones), it wipes-out a lot of tests afterwards.