hello i read your augument.py

[JeonHyeongJunKW]

I'm trying to understand your code as much as possible. But there's something I don't understand. This is it.

matrix = np.identity(4)
matrix[0:3, 0:3] = rotMat
matrix[0:3, 3:4] = tvecs
newMat = np.identity(4)
newMat[1][1] = -1
newMat[2][2] = -1
matrix = np.dot(newMat, matrix)
matrix = matrix.T
glLoadMatrixf(matrix)
drawAxis(1.0)

This code is thought to form a model view matrix according to the position and orientation of the chessboard. However, I don't understand the contents of the code well from the 4th line. Also, I don't understand why the depth value was reversed.