pghazanfari

import numpy as np

def perspective_fov(fov, aspect_ratio, near_plane, far_plane):
	num = 1.0 / np.tan(fov / 2.0)
	num9 = num / aspect_ratio
	return np.array([
		[num9, 0.0, 0.0, 0.0],
		[0.0, num, 0.0, 0.0],
		[0.0, 0.0, far_plane / (near_plane - far_plane), -1.0],
		[0.0, 0.0, (near_plane * far_plane) / (near_plane - far_plane), 0.0]

pghazanfari

def surrounding(x, idx, radius=1, fill=0):
    """ 
    Gets surrounding elements from a numpy array 
  
    Parameters: 
    x (ndarray of rank N): Input array
    idx (N-Dimensional Index): The index at which to get surrounding elements. If None is specified for a particular axis,
        the entire axis is returned.
    radius (array-like of rank N or scalar): The radius across each axis. If None is specified for a particular axis, 
        the entire axis is returned.