Terraria shadows

This is a really big thing I realllly want to add into my game, I want to add the shadows in the ground like in Terraria, if you don’t know what I am talking about look up Terraria and look at the dirt under the players feet. It fades into black, I reallly want to do this because it would add a lot of dynamic to the game. Does anyone have any ideas?

make the player always emit a shadow sprite into the ground?

This isn’t the best solution; probably the most laggiest solution

Make it to where every block has a circular shadow that has a translucent opacity. Make it to where when they go on top of each other, it gets a more opaque visibility of black.