19粒子效果

实现获取子弹，发射子弹的效果：

获得子弹：

public class GetBulletCmd implements CommandExecutor {
    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
        if (sender instanceof Player) {
            Player player = (Player) sender;

            // 添加物品
            PlayerInventory inventory = player.getInventory();
            if (inventory.firstEmpty() != -1) {
                ItemStack bullet = BulletFactory.getBullet();
                inventory.addItem(bullet);

                player.playSound(player.getLocation(), Sound.ENTITY_ITEM_PICKUP, 1, 1);
                player.sendMessage("获得子弹" + bullet.getAmount() + "发");
            } else {
                player.sendMessage("背包已满");
            }
        } else {
            sender.sendMessage("该指令只能由玩家执行");
        }
        return true;
    }
}

发射子弹：

public class BulletShootEventListener implements Listener {

    @EventHandler
    public void onBulletShoot(PlayerInteractEvent event) {
        Player player = event.getPlayer();
        Action action = event.getAction();
        EquipmentSlot hand = event.getHand();
        if (checkMainHandAndRightClick(action, hand)) {

            // 检查背包里是否存在子弹
            ItemStack itemHold = event.getItem();
            if (BulletFactory.isBullet(itemHold)) {
                // 扣除数量
                itemHold.setAmount(itemHold.getAmount() - 1);
                player.sendMessage("剩余子弹" + ChatColor.RED + itemHold.getAmount() + ChatColor.WHITE + "发");

                player.getWorld().playSound(player.getLocation(), Sound.ENTITY_ARROW_SHOOT, 1, 1);

                // 发射子弹
                new BulletShootEffect(player)
                        .start();
            }
        }

    }

    /**
     * 检查是 主手和右键
     */
    private boolean checkMainHandAndRightClick(Action action, EquipmentSlot hand) {
        return hand == EquipmentSlot.HAND &&
                (action == Action.RIGHT_CLICK_AIR || action == Action.RIGHT_CLICK_BLOCK);
    }
}

渲染粒子：

public class BulletShootEffect {

    private int executeCount = 0;               // 当前执行次数
    private int maxExecuteCount = 50;          // 最大执行次数

    /**
     * 粒子必备信息
     */
    private Particle particle = Particle.RAIN;      // 红石
    Color startColor = Color.fromRGB(174, 214, 241);        // 起始颜色
    Color endColor = Color.fromRGB(108, 52, 131);           // 结束颜色
    int particleAmount = 1;                                 // 粒子数量
    double particleSpeed = 1;                               // 粒子速度
    double fliedDistance = 0;                             // 粒子飞行距离
    double maxDistance = 50;                               // 最大飞行距离

    /**
     * 初始化
     */
    Location startLocation;                                 // 起始位置
    Vector startDirection;                                  // 起始方向
    World world;                                            // 世界
    Player shooter;                                         // 发射者

    public BulletShootEffect(Player shooter) {
        this.shooter = shooter;
        this.world = shooter.getWorld();
        this.startLocation = shooter.getEyeLocation();
        this.startDirection = this.startLocation.getDirection();
    }

    public void start() {
        BukkitRunnable bukkitRunnable = new BukkitRunnable() {

            @Override
            public void run() {

                // 计算当前的位置   开始位置 + 方向 * 飞行距离
                Location currentLocation = startLocation.clone().add(startDirection.clone().multiply(fliedDistance));
                // 适当位置结束
                if (executeCount >= maxExecuteCount || fliedDistance >= maxDistance) {
                    // 显示击中效果，兜底
                    showHitEffect(currentLocation, null);
                    return;
                }

                // 显示粒子
                Particle.DustOptions calculatedColor = calculateCurrentColor();
                world.spawnParticle(particle, currentLocation, particleAmount, 0, 0.1, 0.1, calculatedColor);

                // 受击判定 RayTraceEntitys
                RayTraceResult result = world.rayTraceEntities(currentLocation, startDirection, 1, 0.5, entity -> entity != shooter && entity instanceof LivingEntity);
                if (Objects.nonNull(result)) {
                    // 显示击中效果
                    showHitEffect(currentLocation, result.getHitEntity());
                    return;
                } else {
                    Block block = world.getBlockAt(currentLocation);
                    if (!block.isPassable()) {
                        // 显示击中效果
                        showHitEffect(currentLocation, null);
                        return;
                    }
                }

                executeCount++;
                fliedDistance += particleSpeed;
            }

            /**
             * 计算进度，通过RGB计算颜色
             */
            private Particle.DustOptions calculateCurrentColor() {
                // 进度百分比
                double progress = fliedDistance / maxDistance;
                int red = (int) (startColor.getRed() + (endColor.getRed() - startColor.getRed()) * progress);
                int green = (int) (startColor.getGreen() + (endColor.getGreen() - startColor.getGreen()) * progress);
                int blue = (int) (startColor.getBlue() + (endColor.getBlue() - startColor.getBlue()) * progress);

                return new Particle.DustOptions(Color.fromRGB(red, green, blue), 1);
            }

            /**
             * 显示击中效果
             */
            private void showHitEffect(Location currentLocation, Entity hitEntity) {
                if (Objects.isNull(hitEntity)) {
                    // 没有击中实体

                    Block block = world.getBlockAt(currentLocation);
                    if (block.getType() != Material.AIR) {
                        // 击中方块
                        BlockBreakEvent blockBreakEvent = new BlockBreakEvent(block, shooter);
                        Bukkit.getPluginManager().callEvent(blockBreakEvent);
                        if (!blockBreakEvent.isCancelled()) {
                            // 没有被取消，打掉方块，播放方块破碎效果
                            world.playEffect(currentLocation, Effect.STEP_SOUND, block.getType());
                            // 移除方块
                            block.setType(Material.AIR);
                        }
                    }
                } else {
                    // 如果是LivingEntity
                    if (hitEntity instanceof LivingEntity) {
                        LivingEntity livingEntity = (LivingEntity) hitEntity;
                        // 造成伤害
                        livingEntity.damage(10, shooter);

                        // 播放击中效果，红石碎片模拟血液
                        world.spawnParticle(Particle.RAIN, currentLocation, 10, 0.5, 0.5, 0.5, 0, new Particle.DustOptions(Color.RED, 1));
                        shooter.sendMessage("击中" + livingEntity.getName() + "， 对方剩余血量" + livingEntity.getHealth());
                        livingEntity.sendMessage("你被" + shooter.getName() + "击中， 剩余血量" + livingEntity.getHealth());
                    }
                }

                // 取消任务
                cancel();
            }

        };
        // 每tick执行一次
        bukkitRunnable.runTaskTimer(MyPlugin.instance, 0, 1);
    }

}

工具类：

public class BulletFactory {
    /**
     * 获取子弹
     */
    public static ItemStack getBullet() {
        ItemStack itemStack = new ItemStack(Material.ARROW, 16);
        ItemMeta itemMeta = itemStack.getItemMeta();
        itemMeta.setDisplayName("子弹");
        itemStack.setItemMeta(itemMeta);

        return itemStack;
    }

    /**
     * 检查是否是子弹
     */
    public static boolean isBullet(ItemStack itemHold) {
        return itemHold != null &&
                itemHold.getType() == Material.ARROW &&
                itemHold.getItemMeta() != null &&
                itemHold.getItemMeta().getDisplayName().equals("子弹");
    }
}