Re: Circle - Square Collision Detection

guitarstrummr@[EMAIL PROTECTED]
 wrote:
> Anyone have any quick and simple code for collision detection between
> a circle and a square?

    Check the distances between the centers first; eliminate the case
where the circle and square are far enough apart that they can't
possibly touch.  After that, do a signed point to line distance
calculation
for each edge of the square vs. the center of the circle.  If the
signed distance is less than the radius of the circle for all edges,
you have a collision.

    Work with squared distances; don't bother with the square roots.
See "http://mathworld.wolfram.com/Point-LineDistance2-Dimensional.html",
eq. (11), but don't bother with the absolute value.  Pick a consistent
winding order (clockwise or counterclockwise) for the edges of your
squares,
so a positive signed distance will always indicate "outside".   It's
mostly adds and multiplies; few divides, no trig functions.

    If you have to rotate and translate the square and circle, find
a site that explains basic graphics math and learn how to use rotation
matrices.

				John Nagle