[1.12.2] Delaying Tasks

[unassigned]

Hello, 

I have a tile entity that produces explosions around an area every so often. However, I want to spawn in particles, wait until those particles decay (20ish ticks), then create the explosion. I already have this working, however, I'm not too sure if I should be scheduling tasks, or if there is an another, better way to do this.

Here is my current code:

    public void explosionFX(int x, int y, int z)
    {
        ((WorldServer) world).spawnParticle(EnumParticleTypes.ENCHANTMENT_TABLE, true, x, y, z, 100, 0, 0, 0, 3D);

        Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                world.createExplosion(null, x, y, z, 100, false);
            }
        }, 1000); //1 second
    }

I could not base this event off tile entity ticks, as this function is already run every 100 ticks.

Thanks.

[V0idWa1k3r]

20 minutes ago, unassigned said:

I could not base this event off tile entity ticks

Why? Using TE's update is the preferred way of doing this.

 

21 minutes ago, unassigned said:

Timer

Since you are using timer your code will crash the game at some point without any warning with a ConcurrentModificationException, because Timer utilizes a different thread to run the passed runnable afaik. And the game isn't thread safe, especially when it comes to the world.

[unassigned]

12 minutes ago, V0idWa1k3r said:

Why? Using TE's update is the preferred way of doing this.

  

Since you are using timer your code will crash the game at some point without any warning with a ConcurrentModificationException, because Timer utilizes a different thread to run the passed runnable afaik. And the game isn't thread safe, especially when it comes to the world.

Well, for some reason, I was trying to execute both these tasks at the same rate (5 seconds), when in reality I could just separate the if statements, and make the explosion go off after 6 seconds.

However, (maybe this is just my poor understanding of what's actually happening when modulating my TE's ticks) I get a weird phenomenon in which the explosion seems to sync up during the first few calls, but then they become gradually more unsynced for a few more calls, then returns back to being synced again. Here is what I have:

        if(ticksAlive % 100 == 0) //every 5 seconds
        {
            randX = this.pos.getX()+(world.rand.nextInt(8 + 1 + 8) - 8);
            randZ = this.pos.getZ()+(world.rand.nextInt(8 + 1 + 8) - 8);
            groundY = (world.getHeight(randX, randZ));
            strength = world.rand.nextInt(5 + 1 - 2) + 2;

            ((WorldServer) world).spawnParticle(EnumParticleTypes.ENCHANTMENT_TABLE, true, randX, groundY, randZ, 1000, 0, 0, 0, 3D);
        }
        if(ticksAlive % 120 == 0) //every 6 seconds
        {
            world.newExplosion(null, randX, groundY, randZ, strength , false, true);
        }

  

Edited November 30, 2018 by unassigned
grammar

[V0idWa1k3r]

4 minutes ago, unassigned said:

I get a weird phenomenon in which the explosion seems to sync up during the first few calls, but then they become gradually more unsynced for a few more calls, then returns back to being synced again.

Well, think about it. You have 2 events, one happening every 5 seconds the other every 6 seconds. Let's chart the timestamps of the events:

5, 10, 15, 20, 25, 30, 35, 40, ...

6, 12, 18, 24, 30, 36, 42, 48, ...

Note how there are timestamps where both events will occure(30 is one, 60 would be the other one, etc).

[unassigned]

2 minutes ago, V0idWa1k3r said:

Well, think about it. You have 2 events, one happening every 5 seconds the other every 6 seconds. Let's chart the timestamps of the events:

5, 10, 15, 20, 25, 30, 35, 40, ...

 6, 12, 18, 24, 30, 36, 42, 48, ...

Note how there are timestamps where both events will occure(30 is one, 60 would be the other one, etc).

Oh, I see. So I'd just have to create another tick counter and reset that once task 2 is complete? Or is there a better way to do this?

[V0idWa1k3r]

What do you want to happen? What behaviour do you want? Having 2 counters will not change anything.

[unassigned]

1 minute ago, V0idWa1k3r said:

What do you want to happen? What behaviour do you want? Having 2 counters will not change anything.

What I'm looking for is this:

> Spawn in the particle, (its currently an enchantment particle) let it move into its final target position, then decay

> after the particle decay (which is about 1.5 seconds) create the explosion at that target position

I have everything but the timing down.

[V0idWa1k3r]

Well, there are two options I see.

The first one would be to split the process - have a separate Entity that behaves like your particle and renders like one(but is an Entity, not a Particle). Since you have full control over that entity you know when it decays and when it does - spawn your explosion from the entity's class.

The second one is to create a task system. Basically have a task class that contains a counter and the data needed to spawn the explosion - position, strength etc. Then when you spawn the particle add a new task to a collection. Every tick iterate the collection and increment/decrement/compare the counter. When the condition is satisfied spawn the explosion and remove the task from the collection. Something like this:

class ExplosionTask implements INBTSerializable<NBTTagCompound>
{
    int timestamp;
    BlockPos spawnPos;
    float strength;
    
    public static ExplosionTask newTask(int currentTick, int delay, BlockPos pos, float strength)
    {
        ExplosionTask ret = new ExplosionTask();
        ret.timestamp = currentTick + delay;
        ret.spawnPos = pos;
        ret.strength = strength;
    }
    
    public boolean shouldFire(int ticks)
    {
        return ticks >= this.timestamp;
    }
}

class TE extends TileEntity implements ITickable
{
    IList<ExplosionTask> tasks = Lists.newArrayList();
    
    void onUpdate()
    {
        if (counter % 100 == 0)
        {
            ...
            // Spawn particle
            ...
        
            tasks.add(ExplosionTask.newTask(counter, 120, pos, strength));
        }
        
        Iterator<ExplosionTask> it = tasks.getIterator();
        while(it.hasNext())
        {
            ExplosionTask task = it.next();
            if (task.shouldFire(counter))
            {
                world.newExplosion(null, task.spawnPos, strength, ...);
                it.remove();
            }
        }
    }
}

 

[unassigned]

Spoiler

18 minutes ago, V0idWa1k3r said:

Well, there are two options I see.

The first one would be to split the process - have a separate Entity that behaves like your particle and renders like one(but is an Entity, not a Particle). Since you have full control over that entity you know when it decays and when it does - spawn your explosion from the entity's class.

The second one is to create a task system. Basically have a task class that contains a counter and the data needed to spawn the explosion - position, strength etc. Then when you spawn the particle add a new task to a collection. Every tick iterate the collection and increment/decrement/compare the counter. When the condition is satisfied spawn the explosion and remove the task from the collection. Something like this:

class ExplosionTask implements INBTSerializable<NBTTagCompound>
{
    int timestamp;
    BlockPos spawnPos;
    float strength;
    
    public static ExplosionTask newTask(int currentTick, int delay, BlockPos pos, float strength)
    {
        ExplosionTask ret = new ExplosionTask();
        ret.timestamp = currentTick + delay;
        ret.spawnPos = pos;
        ret.strength = strength;
    }
    
    public boolean shouldFire(int ticks)
    {
        return ticks >= this.timestamp;
    }
}

class TE extends TileEntity implements ITickable
{
    IList<ExplosionTask> tasks = Lists.newArrayList();
    
    void onUpdate()
    {
        if (counter % 100 == 0)
        {
            ...
            // Spawn particle
            ...
        
            tasks.add(ExplosionTask.newTask(counter, 120, pos, strength));
        }
        
        Iterator<ExplosionTask> it = tasks.getIterator();
        while(it.hasNext())
        {
            ExplosionTask task = it.next();
            if (task.shouldFire(counter))
            {
                world.newExplosion(null, task.spawnPos, strength, ...);
                it.remove();
            }
        }
    }
}

 

 

 

The task method worked flawlessly. Thank you very much for your help.