DeepFaceLive/xlib/math/math_.py

63 lines
1.8 KiB
Python

import math
import numpy as np
import numpy.linalg as npla
def rotation_matrix_to_euler(R : np.ndarray) -> np.ndarray:
sy = math.sqrt(R[0,0] * R[0,0] + R[1,0] * R[1,0])
singular = sy < 1e-6
if not singular :
x = math.atan2(R[2,1] , R[2,2])
y = math.atan2(-R[2,0], sy)
z = math.atan2(R[1,0], R[0,0])
else :
x = math.atan2(-R[1,2], R[1,1])
y = math.atan2(-R[2,0], sy)
z = 0
return np.array([x, y, z])
def segment_length(p1 : np.ndarray, p2 : np.ndarray):
"""
p1 (2,)
p2 (2,)
"""
return npla.norm(p2-p1)
def segment_to_vector(p1 : np.ndarray, p2 : np.ndarray):
"""
p1 (2,)
p2 (2,)
"""
x = p2-p1
x /= npla.norm(x)
return x
def intersect_two_line(a1, a2, b1, b2) -> np.ndarray:
"""
Returns the point of intersection of the lines (not segments) passing through a2,a1 and b2,b1.
a1: [x, y] a point on the first line
a2: [x, y] another point on the first line
b1: [x, y] a point on the second line
b2: [x, y] another point on the second line
"""
s = np.vstack([a1,a2,b1,b2]) # s for stacked
h = np.hstack((s, np.ones((4, 1)))) # h for homogeneous
l1 = np.cross(h[0], h[1]) # get first line
l2 = np.cross(h[2], h[3]) # get second line
x, y, z = np.cross(l1, l2) # point of intersection
if z == 0: # lines are parallel
return (float('inf'), float('inf'))
return np.array( [x/z, y/z], np.float32 )
def polygon_area(poly : np.ndarray) -> float:
"""
calculate area of n-vertices polygon with non intersecting edges
poly np.ndarray (n,2)
"""
return float( np.abs(np.sum( poly[:,0] * np.roll( poly[:,1], -1 ) - poly[:,1] * np.roll( poly[:,0], -1 ) ) / 2) )