Posted by MartinW on Mar 19, 2014; 3:24pm
URL: https://forum.world.st/Calculate-angle-between-two-vectors-probably-Igor-tp4749351p4749824.html

Nicolai Hess wrote

in testIsInFieldOfVision
subject has velocity 100@0, I understand this as "moves from left to right".
testobject other2 and other3 are above and below subect, and not behind and
in front, both should be visible with the fieldOfView.

Oh, thank you. I made a new testcase. Which is unfortunately passing :( So i am still looking for a solution…

Nicolai Hess wrote

Btw. the field of view is rather big, 0.75*Float Pi is 135 degree, but
clock *and* counterclockwise
->  270 degree field of view.

That's correct. Most birds have the eyes on the sides of their heads - thus they have a wide visual field. Some as wide as 360 degrees.