\[
2^{32} n \le \left(\frac{x}{8}\right)^2 + \left(\frac{z}{8}\right)^2 < 2^{32}\left(n + \frac12\right)
\]
$$
2^{32} n \le \left(\frac{x}{8}\right)^2 + \left(\frac{z}{8}\right)^2 < 2^{32}\left(n + \frac12\right)
$$
The issue is in the expression
MathHelper.sqrt((float)(i * i + j * j))here, i * i + j * j can overflow the 231 - 1 limit of a 32-bit signed integer even before getting converted into float. The next 231 values become negative so sqrt returns NaN.
i and j correspond to the terrain generation coordinates, which for The End are x/8 and z/8.
A 32-bit signed integer can take 232 unique values before getting wrapped on itself, which can be interpreted as only the first half being positive.
So terrain generates only when
where n = 0, 1, 2, …
The horizontal distance r from the origin at which terrain generates therefore satisfies
Note that x/8 and z/8 in are evaluated as integers, so the strict inequality can be replaced with the exact upper bounds
Interestingly, the area of the nth ring is approximately
which does not depend on n, meaning that all the rings have equal area.
in my inequalities above, n = 0, 1, 2, … can be thought of as the number of times the 32-bit signed integer has been overflown. for example, the first ring occurs when it was overflown n = 1 time.