How can I apply a stamped metal effect into an image?

I am trying to make stamped metal effect into an image, so I go with applying bevel effect like in photoshop and I came across this question. This image for reference about what am I trying to achieve.

import cv2import numpy as npfrom matplotlib import pyplot as pltfrom matplotlib import cmfrom PIL import Imageimport scipydef nothing(x):    passif __name__ == '__main__':    mask = np.zeros((200,400,1), np.uint8)    mask = cv2.rectangle(mask, (30,30), (180,180), 255, -1)    mask = cv2.circle(mask, (30,30), 50, 0, -1)    mask = cv2.circle(mask, (180,180), 50, 0, -1)    mask = cv2.circle(mask, (300,100), 75, 255, -1)    mask = cv2.circle(mask, (300,100), 25, 0, -1)    mask = cv2.rectangle(mask, (313,88), (338,110), 0, -1)    cv2.namedWindow('Bevel')    while(True):        light_angle = 0        depth = 7        alfa = 1.0        shift = 128        kernel_dist = np.ones((3,3), np.uint8)        dist = cv2.morphologyEx(mask, cv2.MORPH_GRADIENT, kernel_dist)        #dist = cv2.Canny(mask, 50,150)        dist = 255-dist        dist = cv2.distanceTransform(dist, cv2.DIST_L2, cv2.DIST_MASK_5)        _, dist = cv2.threshold(dist, depth, depth, cv2.THRESH_TRUNC)        dist = cv2.blur(dist, (3,3))        #bevel= np.array(dist, dtype=np.uint8) # not used, only to show stuff        #bevel= cv2.equalizeHist(bevel)        d = np.array([[-1,-2,-3],                    [-2, 0, 0],                    [-3, 0, 1]], dtype=np.float32)        d = scipy.ndimage.rotate(d,light_angle)        kernel = d - np.mean(d)        dist2 = cv2.filter2D(dist, cv2.CV_32F, kernel)        maxval = cv2.minMaxLoc(dist2)        dist2 = 128*dist2/maxval[1]        bevel2 = dist2        bevel2 = shift - bevel2 * alfa         bevel2 = np.multiply(bevel2.reshape(mask.shape), mask)/255        bg = np.zeros((200,400,3), np.float32)        bg = cv2.rectangle(bg, (30,30), (180,180), (150,150,0), -1)        bg = cv2.circle(bg, (30,30), 50, (0,0,0), -1)        bg = cv2.circle(bg, (180,180), 50, (0,0,0), -1)        bg = cv2.circle(bg, (300,100), 75, (0,200,0), -1)        bg = cv2.circle(bg, (300,100), 25, (0,0,0), -1)        bg = cv2.rectangle(bg, (313,88), (338,110), (0,0,0), -1)        bg_hsv = cv2.cvtColor(bg, cv2.COLOR_BGR2HSV)        h,s,v = cv2.split(bg_hsv)        v_blend = cv2.add(v,bevel2) #here merging bevel map and image via V channel        bg_hsv_new = cv2.merge([h,s,v_blend])        cv2.imshow('Bevel', cv2.cvtColor(bg_hsv_new, cv2.COLOR_HSV2BGR).astype(np.uint8))        if cv2.waitKey(10) & 0xFF == ord('q'):            break

The question is :

1. Is matrix/method that used on referred question has an actual name? I couldn't find any source that explain how said matrix/method work and how to tune it (such as strength of light, approach angle etc.)

2. Is my implementation of merging bevel map and actual image correct? The result become cool looking reflective metal effect, but that achieved after reducing parameter shift into 0 (where on referred question used constant 128). If not, how to correctly use bevel map that produced?

Result :

Shift = 128

Shift = 0