Level.java tick/render methods

public void tick() {
        for (int i = 0; i < particles.size(); i++) {
            particles.get(i).tick();
        }
        for (int i = 0; i < entities.size(); i++) {
            entities.get(i).tick();
        }
        for (int i = 0; i < projectiles.size(); i++) {
            projectiles.get(i).tick();
        }
        remove();
    }

public void render(int xScroll, int yScroll, Screen screen) {
        screen.setOffset(xScroll, yScroll);
        int x0 = xScroll >> 4;
        int x1 = (xScroll + screen.width + 16) >> 4;
        int y0 = yScroll >> 4;
        int y1 = (yScroll + screen.height + 16) >> 4;
        for (int y = y0; y < y1; y++) {
            for (int x = x0; x < x1; x++) {
                getTile(x, y).render(x, y, screen);
            }
        }
        for (int i = 0; i < particles.size(); i++) {
            particles.get(i).render(screen);
        }
        for (int i = 0; i < entities.size(); i++) {
            entities.get(i).render(screen);
        }
        for (int i = 0; i < projectiles.size(); i++) {
            projectiles.get(i).render(screen);
        }
    }