The directional lights' shadow does not look right

The directional lights’ shadow does not look right

I have never seen any shadow like that in any renderers for any lights. The shadow is a circle??!!

What is the algorithm behind the directional lights’ shadow?

@Evgeni_Popov can help with that, he is the king of the shadows

Huh, Popov taught me how to solve this can check this topic :wink: