The path found is not the shortest path

[miblooming]

In the code, the distance estimation uses the "Chebyshev distance", which will result in the path found not being the shortest path. The "Manhattan distance" should be used.

public static int GetDist(Point a, Point b)
{
	int diff_columns = Mathf.Abs( b.column - a.column );
	int diff_rows    = Mathf.Abs( b.row - a.row );

	int d1 = diff_rows;
	int d2 = diff_columns;
	if (d1 > d2)
	{
		(d1, d2) = (d2, d1);
	}

	return (d2 - d1) + (int)(d1 * SQRT_2 );
}