How do I have an object face the mouse in p5?

Question

I'm have a problem making an object face the mouse and the websites tutorials don't help!

function draw() {
    background(0, backgroundColor2, 0); 
    cursor('crosshair.png')
    frameRate(1000);
    angleMode(DEGREES);  
    imageMode(CORNER)
    let a = atan2(mouseY - height / 2, mouseX - width / 2);
    rotate(a);
    image(gun, width/2, height/2, 40, 40);
}

Answer 1

The object is rotating but it is rotating on 0, 0

So if you want the object to rotate on the center of the screen then,

    function draw() {
       background(0, backgroundColor2, 0); 
       cursor('crosshair.png')
       frameRate(1000);
       angleMode(DEGREES);  
       imageMode(CORNER)
       let a = atan2(mouseY - height / 2, mouseX - width / 2);
       translate(width/2, height/2);
       rotate(a);
       image(gun, 0, 0, 40, 40);
    }

Here is a link for you to understand better https://www.youtube.com/watch?v=o9sgjuh-CBM