How to add aiming mechanic to sidescroller template?

I’m attempting to implement a single line trace from the player to the mouse’s location. However, I’m unsure of how to rotate the vector using the mouse’s position. I’ve looked at several examples for top down shooters and haven’t found much on side scrollers. Any help would be appreciated!


This question has been asked before and a tutorial has been provided by the community here:

Take a look and see if this helps you achieve what you are after.