circleHit: a formulaic hit detection for two circles. Pass in the two objects you want to check against to see if they are in collision.

Circle Hit

function circleHit(circle1, circle2) {
//circle1 is first parameter, circle2 is second parameter
//in bullet vs. enemy circle1 is the current bullet, circle2 is the current enemy

    var c1 = $(circle1); //assigns to new local variable
    var c2 = $(circle2);

    c1.r = c1.width() / 2; //r stands for radius 
    c1.x = c1.position().left + c1.r; 
    c1.y = c1.position().top + c1.r;

    c2.r = c2.width() / 2;
    c2.x = c2.position().left + c2.r;
    c2.y = c2.position().top + c2.r;

    distx = c1.x - c2.x;
    disty = c1.y - c2.y;

    squaredist = (distx * distx) + (disty * disty)
    return squaredist <= (c1.r + c2.r) * (c1.r + c2.r)

}//end circleHit()