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### Re: circular area in a coordinates grid (AoA)

by Marshall (Canon)
 on Mar 19, 2019 at 21:48 UTC ( #1231455=note: print w/replies, xml ) Need Help??

in reply to circular area in a coordinates grid (AoA)

I am quite confused as to the desired output. Your code produces:
```oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
oooooooooooooooooooo
I don't understand what that means? There is a Math::Trig module that can deal with rectangular and spherical coordinates or 2 dimensional versions (x,y and polar,magnitude and angle). Sorry that I'm being dense, but I don't understand the requirement yet.

Update: Just as a wild thought, maybe this is a graphical representation of a target grid? You are going to drop a bomb at a particular coordinate in this grid with a blast radius of X. All of the affected "o's" should turn into "x's". Is that analogy right?

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Re^2: circular area in a coordinates grid (AoA)
by Discipulus (Abbot) on Mar 19, 2019 at 21:59 UTC
> All of the affected "o's" should turn into "x's". Is that analogy right?

Yes! The analogy is a bit crude but describes well what I intended.

L*

There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.
Ok, "crude" works for me as long as it is descriptive!

In cartesian coordinates, The equation of the points on a circle is (x − a)**2 + (y − b)**2 = r**2 where a and b are the coordinates of the center (a, b) and r is the radius. Points within the circle are solutions where x,y result in <= r**2. So this question is given a grid of Horizontal x Vertical discrete points, an x,y "bomb target point" and a radius. The idea is to "color", i.e. fill-in the circle or change all elements to x that are within the circle. The resulting "picture" will look more and more like a smooth circle as the number of elements in the grid increases.

This sort of thing has to happen all the time in video games and I'm sure there are very good algorithms for this. To write my own code, I need to think some more. But, thanks for making the requirement more clear!

Ok, "crude" works for me as long as it is descriptive!

In cartesian coordinates, The equation of the points on a circle is (x -a)**2 + (y -b)**2 = r**2 where a and b are the coordinates of the center (a, b) and r is the radius. Points within the circle are solutions where x,y result in <= r**2. So this question is given a grid of Horizontal x Vertical discrete points, an x,y "bomb target point" and a radius. The idea is to "color", i.e. fill-in the circle or change all elements to x that are within the circle. The resulting "picture" will look more and more like a smooth circle as the number of elements in the grid increases.

This sort of thing has to happen all the time in video games and I'm sure there are very good algorithms for this. To write my own code, I need to think some more. But, thanks for making the requirement more clear!

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