How to get direction only in the x and z direction?

Vector dir = p.getLocation().getDirection();
dir.multiply(3.85);
dir.setY(.5);
p.setVelocity(dir);

This code makes it so that when a player does the action specified in the code above it, it will boost the player forward and a little bit upward depending on where they are looking. The problem is, the boost does not shoot them forward if they are looking straight down or straight up, and this needs to be the case. So pretty much I need the boost to shoot the player forward the same amount no matter if they are looking up, down, or straight forward. Any ideas on how to solve this problem?

 

@MrVeggieTacos
If the X^2+Z^2 < Y^2, do not set the Y value.

 

The player still wouldn't move forward though

 

@MrVeggieTacos
Yes they would. There is nothing limiting the players XZ movement. Try it, and if that somehow happens, post your code.

 

Get the player's X and Z direction, set the Y direction to whatever, and then use them in the set velocity by vector.

I would give a better example, but I'm on my phone, plus I'm eating Popcorn Chicken (Nom nom)