var cfc = function(player, ball) {
    //Rechtecke auf Überlappung überprüfen
    if((ball.x+ball.size/2 < player.x || ball.x-ball.size/2 > player.x+player.size ||
        ball.y-ball.speed/2 > player.y+player.speed || ball.y+ball.speed/2 < player.y)) {
        return;
    }

    //Kollisionsabstände berechnen um die Richtung zu bestimmen
    var diff = [ball.x+ball.size/2 - player.x, player.x+player.size - ball.x,
                ball.y+ball.speed/2 - player.y, player.y+player.speed - ball.y];
    var collision_dir = diff.indexOf(Math.min(diff[0], diff[1], diff[2], diff[3]));

    if(collision_dir === 0) { //Kollision linke Kante (Player)
        ball.xVel = -Math.abs(ball.xVel);
    }
    else if(collision_dir === 1) { //Kollision rechte Kante (Player)
        ball.xVel = Math.abs(ball.xVel);
    }
    else if(collision_dir === 2) { //Kollision obere Kante (Player)
        ball.yVel = Math.abs(ball.yVel);
    }
    else if(collision_dir === 3) { //Kollision untere Kante (Player)
        ball.yVel = -Math.abs(ball.yVel);
    }
};