public static IEnumerable <int2> FindTilesInCircle(this World world, int2 a, int r)
{
var min = world.ClampToWorld(a - new int2(r, r));
var max = world.ClampToWorld(a + new int2(r, r));
for (var j = min.Y; j <= max.Y; j++)
{
for (var i = min.X; i <= max.X; i++)
{
if (r * r >= (new int2(i, j) - a).LengthSquared)
{
yield return(new int2(i, j));
}
}
}
}