Gravity Gun

Hello,
If I spawn a falling sand entity, from a interact event, how can I do the following?
- Keep the sand from turning into a block
- Set the velocity of the falling sand to always follow the players cursor. (within a 4 block reach)

I am trying to recreate the effect of a gravity gun, or the effect of the USE key. (For those who have played valve games) I am making a portal recreate (yes, another one!), and I need a USE key, pick up, falling sand block, cursor trick?
Any ideas?
Yes, you in the back!

 

BlueMustache

I'm not entirely positive that recreating a gravity gun, as it is used in valve games, is entirely possible. If you mean to pick it up and flail it around like in the real deal.

 

It is, but it's not necessarily easy.

 

Garris0n
Really 0.0... good to know.

 

I want a USE style block pick up.
I press say E, which cancels my inventory open event, and will toggle my pick up value to true. The block I'm looking at will become falling sand, and follow my cursor like the real deal.

 

BlueMustache
The E key is not possible. You can make them right/leftclick with the Gravity Gun though.

 

Desle the "E" key fires an InventoryOpenEvent unless I am mistaken, this can be used to toggle the block pickup just as BlueMustache said. I would have no clue how to go about the rest of the code though

 

thats is, if the player has e set up to open their inventory in their controls

 

mike546378
Forgot that. I have mine set to c. But still, not able to detect when they open their inventory.

 

Yes you can? I will worry about that. Any ideas for the rest of the code?

 

Add them to a Arraylist when they open there inventory and then remove them a few ticks later perhaps?

 

I know that, Thank You.
My guestion is the falling sand following the cursor part.

 

Pseudo time
> Get there direction
> Spawn Falling Sand Entity every 20 ticks at the direction there looking
> Remove old entity
> ???
> Profit

 

Any ideas of getting where the player is looking, and setting the sands velocity to move to it?

 

BlockIterator?

 

InventoryOpenEvent is not fired for the player's own inventory (try it and see) - that's done entirely client-side. The event is only fired for opening container blocks with a right-click.

BlueMustache as for getting a FallingBlock entity to remain properly static... good luck Even if you continually reset its velocity to 0, the client still tries to make it fall, and you'll get a horribly twitchy block in front of the player. You need to find some way of tricking the client into thinking the block isn't falling.

Getting it to follow the player's movement isn't too hard - catch the PlayerMoveEvent, and calculate where the block should be held by extending a short Vector in the direction the player is looking, e.g.:

PHP:

Location l = player.getEyeLocation().add(player.getLocation().getDirection().multiply(1.5));


Now if you can get the client to think your FallingBlock is static at that location, you're in business. See this thread for a couple of ideas. Garris0n had a neat idea about creating an invisible bat which you could set the FallingBlock as a passenger for. Then use the code above to move the bat around, and the block should hopefully ride with it. Worth investigating...

 

Thank You, just what I was looking for.
The bat thing is a good idea, and I did not know that about the InventoryEvent.
Also, the location snippit was very helpful.
Thanks Guys!

Also, I already knew about block 36, and the fact that FallingSand is glitched client side.
I was going to use that.
The last thing I need help with, is how would I calculate what the velocity is I need set an Entity to, to make it move to that location.
Say I made a function calcVelocity(Location from, Location to); Returns Vector.
You input the entity's position into "from", and the destination "to", and It will calculate the Vector required, and return it.
What do I need to put in the function, to turn a location into a calculated velocity trajectory?
Thanks, I promise this is the last thing.
- Blue

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

BlueMustache desht CrazyGuy3000

I tried the following.. although it doesn't really work, since it doesn't move your cursor smoothly.. and it gets removed after a while. Anyone knows why?

Code:java

public class GravityBlock {
 
    public static Map<String, GravityBlock> players = new HashMap<String, GravityBlock>();
 
    private Material type;
    private byte data;
    private EntityWitherSkull skull;
    private Entity block;
    private String player;
 
    public GravityBlock(Material type, byte data, Location loc, Player p) {
        this.type = type;
        this.data = data;
        this.player = p.getName();
        spawn(loc);
    }
 
    public void setLocation(Location loc) {
        this.skull.setPosition(loc.getX(), loc.getY(), loc.getZ());
    }
 
    public void remove() {
        this.block.remove();
        this.skull.getBukkitEntity().remove();
        players.remove(this.player);
    }
 
    private void spawn(Location loc) {
        WorldServer world = ((CraftWorld) loc.getWorld()).getHandle();
        EntityWitherSkull skull = new EntityWitherSkull(world);
        skull.setLocation(loc.getX(), loc.getY(), loc.getZ(), 0, 0);
        world.addEntity(skull);
        FallingBlock block = loc.getWorld().spawnFallingBlock(loc, type, data);
        block.setDropItem(false);
        skull.getBukkitEntity().setPassenger(block);
        this.block = block;
        this.skull = skull;
        players.put(this.player, this);
    }
}
 

And this is how I moved it;

Code:java

    @EventHandler
    public void onMove(PlayerMoveEvent e) {
        if (e.getFrom().getPitch() != e.getTo().getPitch() || e.getFrom().getYaw() != e.getTo().getYaw()) {
            if (GravityBlock.players.get(e.getPlayer().getName()) != null) {
                GravityBlock block = GravityBlock.players.get(e.getPlayer().getName());
                @SuppressWarnings("deprecation")
                Location loc = e.getPlayer().getTargetBlock(null, 20).getLocation();
                block.setLocation(loc);
            }
            return;
        }
    }

 

Thank You, very helpful. (very interesting)
I will try integrating this.
I will revise this to the best of my abilities.
For now, this is solved.
Thanks.
- Blue