[1.8.9] Make a Block to a Falling Block

[Darki]

I try to make Blocks that are flying in the air (when something explode under the Blocks) falling on the ground. I have a List with Blocks that "have to fall", but how can I make Blocks falling?

[larsgerrits]

Look at a vanilla block that does that:

BlockSand

and

BlockGravel

.

[Draco18s]

Possibly the parent class, BlockFalling.

[Darki]

Hmm:

public class BlockFalling extends Block
{
    public static boolean fallInstantly;

    public BlockFalling()
    {
        super(Material.sand);
        this.setCreativeTab(CreativeTabs.tabBlock);
    }

    public BlockFalling(Material materialIn)
    {
        super(materialIn);
    }

    public void onBlockAdded(World worldIn, BlockPos pos, IBlockState state)
    {
        worldIn.scheduleUpdate(pos, this, this.tickRate(worldIn));
    }

    /**
     * Called when a neighboring block changes.
     */
    public void onNeighborBlockChange(World worldIn, BlockPos pos, IBlockState state, Block neighborBlock)
    {
        worldIn.scheduleUpdate(pos, this, this.tickRate(worldIn));
    }

    public void updateTick(World worldIn, BlockPos pos, IBlockState state, Random rand)
    {
        if (!worldIn.isRemote)
        {
            this.checkFallable(worldIn, pos);
        }
    }

    private void checkFallable(World worldIn, BlockPos pos)
    {
        if (canFallInto(worldIn, pos.down()) && pos.getY() >= 0)
        {
            int i = 32;

            if (!fallInstantly && worldIn.isAreaLoaded(pos.add(-i, -i, -i), pos.add(i, i, i)))
            {
                if (!worldIn.isRemote)
                {
                    EntityFallingBlock entityfallingblock = new EntityFallingBlock(worldIn, (double)pos.getX() + 0.5D, (double)pos.getY(), (double)pos.getZ() + 0.5D, worldIn.getBlockState(pos));
                    this.onStartFalling(entityfallingblock);
                    worldIn.spawnEntityInWorld(entityfallingblock);
                }
            }
            else
            {
                worldIn.setBlockToAir(pos);
                BlockPos blockpos;

                for (blockpos = pos.down(); canFallInto(worldIn, blockpos) && blockpos.getY() > 0; blockpos = blockpos.down())
                {
                    ;
                }

                if (blockpos.getY() > 0)
                {
                    worldIn.setBlockState(blockpos.up(), this.getDefaultState());
                }
            }
        }
    }

    protected void onStartFalling(EntityFallingBlock fallingEntity)
    {
    }

    /**
     * How many world ticks before ticking
     */
    public int tickRate(World worldIn)
    {
        return 2;
    }

    public static boolean canFallInto(World worldIn, BlockPos pos)
    {
        if (worldIn.isAirBlock(pos)) return true;
        Block block = worldIn.getBlockState(pos).getBlock();
        Material material = block.blockMaterial;
        return block == Blocks.fire || material == Material.air || material == Material.water || material == Material.lava;
    }

    public void onEndFalling(World worldIn, BlockPos pos)
    {
    }
}

But how can I make any Block (not Air) with this to a Falling Block?

[Darki]

Ok I see there is a Constructor with Material. I made a new Object BlockFalling for every block in the List but how can I make the blockfalling fall?

[Draco18s]

Oh for fuck's sake.

 

EntityFallingBlock entityfallingblock = new EntityFallingBlock(worldIn, (double)pos.getX() + 0.5D, (double)pos.getY(), (double)pos.getZ() + 0.5D, worldIn.getBlockState(pos));

[Darki]

Ok I dont get any futher. What I want:

When something explodes, I want to get all Blocks over the explosion, then I want that all this blocks falling down but I dont know why it isnt working:

@SubscribeEvent
public void onExplode(ExplosionEvent e) {
	HashMap<Block,BlockPos> fallingBlocks = getBlocksToFall(e);
	System.out.println(fallingBlocks.keySet().size() + "");
	for (Block b : fallingBlocks.keySet()) {
		BlockPos blockPos = fallingBlocks.get(b);
		EntityFallingBlock entityFallingBlock = new EntityFallingBlock(e.world, blockPos.getX(), blockPos.getY(), blockPos.getZ(), e.world.getBlockState(blockPos));
		entityFallingBlock.shouldDropItem = false;
		e.world.spawnEntityInWorld(entityFallingBlock);
	}
}

private HashMap<Block,BlockPos> getBlocksToFall(ExplosionEvent e){
	List<Integer> xs = new ArrayList<Integer>();
	List<Integer> zs = new ArrayList<Integer>();
	int exY = (int) Math.round(e.explosion.getPosition().yCoord);
	for(BlockPos loc : e.explosion.getAffectedBlockPositions()){
		int x = loc.getX();
		if(!xs.contains(x)){
			xs.add(x);
		}
		int z = loc.getZ();
		if(!zs.contains(z)){
			zs.add(z);
		}
	}
	HashMap<Block,BlockPos> blocksToFall = new HashMap<Block,BlockPos>();
	for(int y = exY; y <= e.world.getHeight(); y++){
		for(int x : xs){
			for(int z : zs){
				BlockPos pos = new BlockPos(x, y, z);
				Block b = e.world.getBlockState(pos).getBlock();
				if(!b.getRegistryName().contains("air")){
					blocksToFall.put(b,pos);
				}
			}
		}
	}
	return blocksToFall;
}

[desht]

Firstly, "isn't working" isn't very helpful.  I'll assume you mean that it just doesn't spawn a falling block rather than it fails with an exception etc.

 

The explosion event is fired before any blocks are actually destroyed, so if you want to spawn a falling block, it's up to you to set the block being replaced with air.  Also, if there's a block underneath, you might want to add a small amount to the falling block's Y co-ord so it isn't considered on the ground (or it will immediately turn back into a real block).  You may also want to give newly spawned falling blocks an initial velocity (based on their position and proximity to the explosion centre) so they fly outwards.

 

Also, a map of Block->BlockPos makes no sense at all.  Block is a singleton class; you'll just end up with one element for each type of block affected.  And I don't follow what your getBlocksToFall() method is doing - why not just iterate over event.getAffectedBlockPositions() directly?

 

Update: OK, I understand what you need better now.  I'd suggest just converting the list of affected locations to a Set<Pair<Integer,Integer>>, where the two ints are the X & Z positions of the affected blocks.  Then for each element, you can iterate upward to world height and convert blocks to falling blocks.  If you work upwards, you shouldn't need to worry about the block underneath being solid.

 

(Also, be sure to test what happens with tile entity blocks, with or without held items).

[Darki]

Yeah this is what I want 

[desht]

Cool.  You'll also want to consider what happens if someone sets off multiple explosions down at bedrock level (the amount of scanning for blocks and more so the number of entities being rapidly created will make your server cry).

[Darki]

Yeah. Not my probleme^^ hm I calculate something: a explosion has a radius of 3 i think you place 5 tnts that is a length of 30 blocks. The world has a 64 height that are 30x6x64 blocks = 11.500 nooooo this will not lagging . Yeah but how can I do that?

[desht]

TNT radius is 6.9, according to the official Wiki.  Now consider a couple of hundred TNT under some amplified biome, or mesa, or extreme hills... that could easily be millions of blocks.  (And it will be your problem if & when your publicly released mod gets fingered as a server killer  )

 

Mitigation might be not to create falling blocks immediately, but add them to a queue of limited (tunable) size.  Then pull a certain (tunable) number from the queue every tick, validate that the block hasn't already changed in the intervening ticks since they were added, and then create the falling block.  And if the queue is full, just don't add them.  A queue of Pair<BlockPos,IBlockState> should work here (remembering that IBlockState object can be validly and cheaply compared with ==).

[Darki]

Yeah this is a good idea but my probleme is that the falling sands doesnt spawn

[Animefan8888]

Yeah this is a good idea but my probleme is that the falling sands doesnt spawn

Post your code.

[Darki]

@SubscribeEvent
public void onExplode(ExplosionEvent e) {
	HashMap<Block,BlockPos> fallingBlocks = getBlocksToFall(e);
	System.out.println(fallingBlocks.keySet().size() + "");
	for (Block b : fallingBlocks.keySet()) {
		BlockPos blockPos = fallingBlocks.get(b);
		EntityFallingBlock entityFallingBlock = new EntityFallingBlock(e.world, blockPos.getX(), blockPos.getY(), blockPos.getZ(), e.world.getBlockState(blockPos));
		entityFallingBlock.shouldDropItem = false;
		e.world.spawnEntityInWorld(entityFallingBlock);
	}
}

private HashMap<Block,BlockPos> getBlocksToFall(ExplosionEvent e){
	List<Integer> xs = new ArrayList<Integer>();
	List<Integer> zs = new ArrayList<Integer>();
	int exY = (int) Math.round(e.explosion.getPosition().yCoord);
	for(BlockPos loc : e.explosion.getAffectedBlockPositions()){
		int x = loc.getX();
		if(!xs.contains(x)){
			xs.add(x);
		}
		int z = loc.getZ();
		if(!zs.contains(z)){
			zs.add(z);
		}
	}
	HashMap<Block,BlockPos> blocksToFall = new HashMap<Block,BlockPos>();
	for(int y = exY; y <= e.world.getHeight(); y++){
		for(int x : xs){
			for(int z : zs){
				BlockPos pos = new BlockPos(x, y, z);
				Block b = e.world.getBlockState(pos).getBlock();
				if(!b.getRegistryName().contains("air")){
					blocksToFall.put(b,pos);
				}
			}
		}
	}
	return blocksToFall;
}

[Animefan8888]

@SubscribeEvent
public void onExplode(ExplosionEvent e) {
	HashMap<Block,BlockPos> fallingBlocks = getBlocksToFall(e);
	System.out.println(fallingBlocks.keySet().size() + "");
	for (Block b : fallingBlocks.keySet()) {
		BlockPos blockPos = fallingBlocks.get(b);
		EntityFallingBlock entityFallingBlock = new EntityFallingBlock(e.world, blockPos.getX(), blockPos.getY(), blockPos.getZ(), e.world.getBlockState(blockPos));
		entityFallingBlock.shouldDropItem = false;
		e.world.spawnEntityInWorld(entityFallingBlock);
	}
}

private HashMap<Block,BlockPos> getBlocksToFall(ExplosionEvent e){
	List<Integer> xs = new ArrayList<Integer>();
	List<Integer> zs = new ArrayList<Integer>();
	int exY = (int) Math.round(e.explosion.getPosition().yCoord);
	for(BlockPos loc : e.explosion.getAffectedBlockPositions()){
		int x = loc.getX();
		if(!xs.contains(x)){
			xs.add(x);
		}
		int z = loc.getZ();
		if(!zs.contains(z)){
			zs.add(z);
		}
	}
	HashMap<Block,BlockPos> blocksToFall = new HashMap<Block,BlockPos>();
	for(int y = exY; y <= e.world.getHeight(); y++){
		for(int x : xs){
			for(int z : zs){
				BlockPos pos = new BlockPos(x, y, z);
				Block b = e.world.getBlockState(pos).getBlock();
				if(!b.getRegistryName().contains("air")){
					blocksToFall.put(b,pos);
				}
			}
		}
	}
	return blocksToFall;
}

You have not followed any of desht's advice, and you should be using the sub event of ExplosionEvent.Start

[Draco18s]

You also can't map Block -> BlockPos.  There are more BlockPos locations than there are Blocks, and the nature of a Hashmap is specifically One-to-One.  Your code right now will create exactly 1 falling block for an explosion taking place inside pure stone.

[desht]

You also can't map Block -> BlockPos.  There are more BlockPos locations than there are Blocks, and the nature of a Hashmap is specifically One-to-One.  Your code right now will create exactly 1 falling block for an explosion taking place inside pure stone.

Yep.  Hence why I suggested a Set<Pair<Integer,Integer>> as the appropriate data structure here; a unique set of (x,z) positions from which columns can be traced vertically upwards.  OP needs to be paying attention

[Animefan8888]

You also can't map Block -> BlockPos.  There are more BlockPos locations than there are Blocks, and the nature of a Hashmap is specifically One-to-One.  Your code right now will create exactly 1 falling block for an explosion taking place inside pure stone.

Yep.  Hence why I suggested a Set<Pair<Integer,Integer>> as the appropriate data structure here; a unique set of (x,z) positions from which columns can be traced vertically upwards.  OP needs to be paying attention

That wont work because theny position is not identifable.

[desht]

Yep.  Hence why I suggested a Set<Pair<Integer,Integer>> as the appropriate data structure here; a unique set of (x,z) positions from which columns can be traced vertically upwards.  OP needs to be paying attention

That wont work because theny position is not identifable.

Explain please?  Seems totally workable to me.

[Draco18s]

I mean really, what's wrong with List<BlockPos>?

 

Also this:

if(!b.getRegistryName().contains("air")){

Block#isAirBlock() much?

[Darki]

Ups this was the wrong code. I changed the hashmap a little time ago. But why dont spawn the falling sand

[Draco18s]

Use your debugger and find out.

[Animefan8888]

Yep.  Hence why I suggested a Set<Pair<Integer,Integer>> as the appropriate data structure here; a unique set of (x,z) positions from which columns can be traced vertically upwards.  OP needs to be paying attention

That wont work because theny position is not identifable.

Explain please?  Seems totally workable to me.

Two things multiple blocks on the same x and z coord, and second how would I even find the correct y coord. Would it be at the highest possible y position there is a block or would it be at the first block with air above them.

[desht]

Two things multiple blocks on the same x and z coord, and second how would I even find the correct y coord. Would it be at the highest possible y position there is a block or would it be at the first block with air above them.

Hence using a Set<Pair> - just store one instance of each (X,Z) pair.  But you're right - you'd need to store a Y-value as well; so perhaps a Map<Pair<Integer,Integer>, Integer> would be better, where the key is (X,Z) and the value is Y.  As for which Y-value, that's up to the mod developer; the smallest Y would be a reasonable choice.