如何延迟每发子弹？ （Java -Slick2d-游戏）

Question

(The event listener is in another class) When Game.render = true, i get a constant stream of bullets that look more like a laser-beam, i want there to be gaps. What I mean is that I would like the bullets to be generated as if they were being fired from a machine gun. I know i should add a time or something, but I'm not sure how to do that, to get the effect I want. Any help would be greatly appreciated because I've been trying to get this to work for about an hour now.

import java.util.ArrayList;
import org.newdawn.slick.GameContainer;
import org.newdawn.slick.Graphics;
import org.newdawn.slick.SlickException;

public class Bullet {

// ArrayList
@SuppressWarnings("unchecked")
static ArrayList<Bullet> arrL = new ArrayList();

public Bullet(int x , int y) throws SlickException{



}

public static void update(GameContainer gc, int u) throws SlickException{

// when the left mouse button is clicked Game.fire = true, the key listener is in   another class
    if(Game.fire){

        Bullet b = new Bullet(5,5);
        arrL.add(b);
        reloaded = false;

    }   if(!reloaded){



    }           
}

public static void renderBullets(GameContainer gc, Graphics g, int x, int y) {

         // draws a new bullet for every 'bullet object' in  the ArrayList called arrL
        for(Bullet b : arrL){

            g.drawRect(x,y,10,10);
            x++;

        }
    }
}

Answer 1

What I do most frequently in this kind of situation is add a time variable that I subtract the delta (the variable you have as u) from every update until it goes below 0, at which point I reset it:

// Set this to whatever feels right for the effect you're trying to achieve.
// A larger number will mean a longer delay.
private static int default_bullet_delay = 500;

private static int time = 0;

public static void update (GameContainer gc, int u) throws SlickException {
    time -= u;
    if (time <= 0 && Game.fire) {
        fireBullet();                 // Replace this with your code for firing the bullet
        time = default_bullet_delay;  // Reset the timer
    }

    // The rest of the update loop...
}

Basically, even if Game.fire is true the bullet won't fire until the timer counts down. Once that happens, the timer is set and the next bullet can't fire until the timer counts down again. If you set this to something reasonably small then there should be a bit of a gap between each bullet.

Answer 2

This is how I did this:

boolean reloaded = false;  // Start with a reload becouse weapon not reload itself
float reloadTime = 100;     // This is the "timer" (the value doesnt matter)
float startReloadTime = 100; // This is the actual reload time

private void shoot(int delta, float screenWidth, float screenHeight) {

    // reload if not reloaded
    if (!reloaded) {
        reloadTime -= 0.5f * delta; // As I said, this is the timer

        // If the reload finished, set the timer back to the reload time
        if (reloadTime <= 0) {
            reloaded = true; // reloaded, we can shoot
            reloadTime = startReloadTime;
        }
    }

    // Shoot only if reloaded
    if (reloaded) {

        // This is some direction calculating, ignore for now
        float mouseWorldX = (x + (mouseX - screenWidth / 2));
        float mouseWorldY = (y + (mouseY - screenHeight / 2));

        float randomX = (float) Math.random() * (2000 / mouseWorldX);
        float randomY = (float) Math.random() * (2000 / mouseWorldY);

        mouseWorldX += randomX;
        mouseWorldY += randomY;

        // Add a new bullet element to the world (where will be rendered)
        world.add(new Shot(world, camera, x + width / 2, y + height / 2, mouseWorldX - 2.5f, mouseWorldY - 2.5f, 5, 5, new Color(1, 0, 0, 1f)));

        // We need to reload
        reloaded = false;
    }
}