keep getting runtime error

[Abdur-rahmaanJ]

: RuntimeWarning: divide by zero encountered in true_divide
result=front255/(255-back)
: RuntimeWarning: invalid value encountered in true_divide
result=front255/(255-back)
: RuntimeWarning: invalid value encountered in greater
result[result>255]=255

[game-stop]

before you do front * 255 / (255-back), you need to check if back has the value 255 (you cannot divide by zero). If the value is 255, you can set the result to white (255)