A quick test with the timeit module suggest that the ** operator is not slower.
x*x and x**2 are exactly the same speed. However, you are correct that x**0.5 is a slow operation. raising something to the power of 0.5 is the same as taking its square root x**0.5 is the same as math.sqrt(x) Here is how I would write the distance check: def is_in_range(enemy, tower): return (enemy.x-tower.x)**2 + (enemy.y-tower.y)**2 <= tower.range**2 --- James Paige On Tue, Nov 03, 2009 at 09:24:50PM -0500, Michael George wrote: > If you find this is too slow, you'll get much better performance by > removing the **'s, they're quite slow compared to other arithmetic. Use > x*x instead of x**2 and square both sides of the inequality to remove > the **0.5. > > P.F.C. wrote: > >I'm not getting the attachment but this might help. > > > >If your doing range as a circle with radius = r then: > > > >if ((enemy.x-tower.x)**2+ (enemy.y-tower.y)**2)**0.5<=r: attack!!! > > > >basically, you'd be using Pythagorean theorem to find the distance to > >check if it attacks or not. > > > >Checking distances for every tower and every unit could become a > >bottle neck but would work. > > > >If you have performance problems you could also incorporate a grid. > >When every unit moves it can do a check to see in what section of the > >map it is found in (ie, grid could have 10x10 tiles in each square) > >and you would only check the distance of creeps in the grids that are > >in range of the tower. > > > >One thing to keep in mind would be that in some cases you may be able > >to stop the iteration as soon as you find someone who is attackable > >(if the tower attacks random creeps) otherwise you just compare the > >distances of the creeps and sort. > > > >You may want to google for circle collision detection > > > > > >-- Maranatha! > >--------------------------------- > >PFC aka Fezzik aka GAB > > > > > >On Tue, Nov 3, 2009 at 8:27 PM, Yanom Mobis <ya...@rocketmail.com > ><mailto:ya...@rocketmail.com>> wrote: > > > > so, I wrote this tower defense game (zip archive attached) and I > > was wondering how I should go about implementing limited range > > (each tower can only shoot so far) in the code. > > > > > > > >
