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Index › Programming Questions & Help › Syntax Questions › how to know if a group of points are inside circle
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how to know if a group of points are inside circle (Read 550 times)
mateooo
how to know if a group of points are inside circle
Apr 26th, 2010, 9:24am  
hello, how can i know if a group of points are inside a circle?

For example if i have a program that consist on a random points or agents moving randomly and an ellipse, how can i know which points are inside my ellipse?

is there any specific approach for making this?

and my second question is how, about if i dont have a sphere but a irregular form, how can i know the points that are inside the irregular form?

thanks

M.
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PhiLho 
Re: how to know if a group of points are inside circle
Reply #1 - Apr 26th, 2010, 9:43am  
Moving target, there... Let's address them.

- Point in circle?
-> dist(point, center of circle) < radius of circle

- Point in ellipse?
-> Not sure, but there must be a formula for that...

- Point in sphere?
We are going 3D?

- Point in irregular form?
2D or 3D?
3D should be fairly hard...
2D with arbitrary shape can be solved the classical way: draw the shape in a PGraphics with some color. Do drawnShape.get(pointToTestX, pointToTestY). If that's the drawing color, the point is in the shape.
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