Player class

public class Player extends Mob {

    private Keyboard input;
    private Sprite sprite;
    private int anim = 0;
    private boolean walking = false;
    private int fireRate = 0;

    private AnimatedSprite down = new AnimatedSprite(SpriteSheet.player_down, 32, 32, 3);
    private AnimatedSprite up = new AnimatedSprite(SpriteSheet.player_up, 32, 32, 3);
    private AnimatedSprite left = new AnimatedSprite(SpriteSheet.player_left, 32, 32, 3);
    private AnimatedSprite right = new AnimatedSprite(SpriteSheet.player_right, 32, 32, 3);

    private AnimatedSprite animSprite = down;

    public Player(Keyboard input) {
        this.input = input;
    }

    public Player(int x, int y, Keyboard input) {
        this.x = x;
        this.y = y;
        this.input = input;
        fireRate = RockProjectile.FIRE_RATE;
        sprite = animSprite.getSprite();
    }

    public void update() {
        if (walking) animSprite.update();
        else animSprite.setFrame(0);
        if (fireRate > 0) fireRate--;
        double xa = 0, ya = 0;
        double speed = 2.0;
        if (anim < 7500) anim++;
        else anim = 0;
        if (input.up) {
            animSprite = up;
            ya -= speed;
        } else if (input.down) {
            animSprite = down;
            ya += speed;
        }
        if (input.left) {
            animSprite = left;
            xa -= speed;
        } else if (input.right) {
            animSprite = right;
            xa += speed;
        }

        if (xa != 0 || ya != 0) {
            move(xa, ya);
            walking = true;
        } else {
            walking = false;
        }
        clear();
        updateShooting();
    }

    private void clear() {
        for (int i = 0; i < level.getProjectiles().size(); i++) {
            Projectile p = level.getProjectiles().get(i);
            if (p.isRemoved()) level.getProjectiles().remove(i);
        }
    }

    private void updateShooting() {
        if (Mouse.getButton() == 1 && fireRate <= 0) {
            double dx = Mouse.getX() - Game.getWindowWidth() / 2;
            double dy = Mouse.getY() - Game.getWindowHeight() / 2;
            double dir = Math.atan2(dy, dx);
            shoot((int) x, (int) y, dir);
            fireRate = RockProjectile.FIRE_RATE;
        }
    }

    public void render(Screen screen) {
        sprite = animSprite.getSprite();
        screen.renderMob(x - 16, y - 16, sprite);
    }

}