For the past couple days, I've been trying to figure out how leaf generation works. And I just don't understand the giant mess of ifs and fors in Minecraft's tree generators. Can someone help me understand what each thing does, or at least make it a little easier to understand.

Edited March 5, 20187 yr by Emerald_Galaxy

I have a tutorial on tree generation, but admit I don't go into any detail about the leaf gen itself. My tutorial is here: http://jabelarminecraft.blogspot.com/p/minecraft-modding-custom-tree-with.html

 

Regarding leaf generation it isn't really that difficult. I find the best way is to copy the code into a new class and then refactor each of the variables with a more useful name as you figure each one out. Then the whole thing can become more clear rather than a bunch of fields named j1, k2 and such.

 

For example, if I took the code for the leaf generation of a small oak tree and refactored it, the code might looks something like this:

        for (int foliageY = parBlockPos.getY() - 3 + height; foliageY <= parBlockPos.getY() + height; ++foliageY)
        {
            int foliageLayer = foliageY - (parBlockPos.getY() + minHeight);
            int foliageLayerRadius = 1 - foliageLayer / 2;

            for (int foliageX = parBlockPos.getX() - foliageLayerRadius; foliageX <= parBlockPos.getX() + foliageLayerRadius; ++foliageX)
            {
                int foliageRelativeX = foliageX - parBlockPos.getX();

                for (int foliageZ = parBlockPos.getZ() - foliageLayerRadius; foliageZ <= parBlockPos.getZ() + foliageLayerRadius; ++foliageZ)
                {
                    int foliageRelativeZ = foliageZ - parBlockPos.getZ();

                    // Fill in layer with some randomness
                    if (Math.abs(foliageRelativeX) != foliageLayerRadius || Math.abs(foliageRelativeZ) != foliageLayerRadius || parRandom.nextInt(2) != 0 && foliageLayer != 0)
                    {
                        BlockPos blockPos = new BlockPos(foliageX, foliageY, foliageZ);
                        IBlockState state = parWorld.getBlockState(blockPos);

                        if (state.getBlock().isAir(state, parWorld, blockPos) || state.getBlock().isLeaves(state, parWorld, blockPos))
                        {
                            setBlockAndNotifyAdequately(parWorld, blockPos, blockStateLeaves);
                        }
                    }
                }
            }
        }

 

So in this case if you think about it, the outermost loop is working in the vertical (Y) direction from the base location to 3 below the height (of the tree) to the height. That makes sense right, cause if you think of a small minecraft tree there are three layers of leaves at the top.

 

The foliageLayer indicates each of the layers as -2, -1 and 0

 

The radius of each layer is 1 - foliageLayer / 2. So for the bottom it is 2 (= 1 - (-2)/2), the middle is also 2 (because 1.5 as int will be rounded up) and the top is 1. Note that in the next for loop that this "radius" is subtracted and added to create the X range so it means the center is also added. So the full width of the bottom two layers is 5 and the top is 3.

 

So the generation simply loops through all those positions and uses a bit of randomness to make a couple gaps.

 

That's pretty much it, except the tree trunk is generated afterwords and will go right up through those leaves.

 

I suggest you do similar investigation for other tree types. It really, really helps to have a picture of the tree type to compare with as the numbers will usually make more sense that way.

What a coincidence, I was actually about to use that tutorial since it was the only one to actually label them.

Also, I have tried copying other trees leaf gen as well as messing with the variables, but both ended up just making a single leaf appear.

 

Thanks.

I want to make a tree with leaves that start wide on the bottom and get thinner as they get higher, kinda like a pine. Any ideas on how I can do that

Calculate the distance of the current leaf position from the top.

Perform some math, r = f(d)

I can do that, but I was most worried about changing the width each time.
 

21 minutes ago, Emerald_Galaxy said:

I can do that, but I was most worried about changing the width each time.
 

That's what f(d) does. It computes the radius based on the distance from the top of the tree. Presumably f(0) is 0, and f(n+1) is greater than or equal to f(n).

I realize not everyone is strong at math, so you can also do it sort of "dumb". You can literally just write code to place each layer of blocks. In fact, you can even just place it block by block. While it will be more lines of code, there is nothing logically wrong, and it doesn't take that much time since each line is mostly cut and paste.

Ok, i'll experiment a little more and see if any more questions arise. Thank you.

Ok a new problem. My leaves decay when I make the radius higher than default

how would I make the leaves radius go down by 1 for each layer

Sounds like your f(n) is equal to n, you probably want n/2

Its not that the radius is the same size, its that I cant seem to make the radius go down by 1 every layer, instead of by 1 every 2 layers

Also what can I do to have varying leaf shapes on different parts of the tree

there's this weird graphic bug involving the leaves which is annoying. When the leaves cover another leaf, it makes it invisible. I looked at the BlockLeaves class and couldn't find anything related to this. Anyone have a solution?

 

1 hour ago, Emerald_Galaxy said:

Its not that the radius is the same size, its that I cant seem to make the radius go down by 1 every layer, instead of by 1 every 2 layers

function int getRadius(int distance_from_top_of_tree) {

    return distance_from_top_of_tree;

}

Thanks but I already fixed it.

Still would like to know about the leaves bug though

Edited March 7, 20187 yr by Emerald_Galaxy

#PostYourCode

LeafBase.java

public class LeafBase extends BlockLeaves implements ModelInterface {
	
	private Item fruit;
	
	public LeafBase(String name, Item fruit, SoundType sound, Float hardness, Float blastResist, Float brightness, Integer isUnbreakable) {
		
		setUnlocalizedName(name);
		setRegistryName(name);
		
		setSoundType(sound);
		setHardness(hardness);
		setResistance(blastResist);
		setLightLevel(brightness);
		setLightOpacity(1);
		
		if(isUnbreakable == 1) {
			setBlockUnbreakable();
		}
		
		this.fruit = fruit;
		
		setDefaultState(this.blockState.getBaseState().withProperty(CHECK_DECAY, Boolean.valueOf(false)).withProperty(DECAYABLE, Boolean.valueOf(false)));
		
		ModBlocks.BLOCKS.add(this);
		ModItems.ITEMS.add(new ItemBlock(this).setRegistryName(this.getRegistryName()));
		
	}
	
	public Item getItemDropped(IBlockState state, Random rand, int fortune) {
		
		return fruit;
		
	}
	
	public ItemStack getSilkTouchDrop(IBlockState state) {
		
		return new ItemStack(Item.getItemFromBlock(this), 1);
		
	}
	
	public int quantityDropped(Random random) {
		
		if(random.nextInt(200) == 0) {
			
			return 1;
			
		} else {
			
			return 0;
			
		}
		
	}
	
	@Override
	public List<ItemStack> onSheared(ItemStack item, IBlockAccess world, BlockPos pos, int fortune) {
		
		return NonNullList.withSize(1, new ItemStack(this, 1));
		
	}
	
	@Override
	public boolean isOpaqueCube(IBlockState state) {
		
		return false;
		
	}
	
	@Override
	public BlockRenderLayer getBlockLayer() {
		
		return BlockRenderLayer.CUTOUT_MIPPED;
		
	}
	
	@Override
	public EnumType getWoodType(int meta) {
		
		return null;
		
	}
	
	@Override
	public IBlockState getStateFromMeta(int meta) {
		
		return this.getDefaultState();
		
	}
	
	@Override
	public int getMetaFromState(IBlockState state) {
		
		return 0;
		
	}
	
	@Override
	protected BlockStateContainer createBlockState() {
		
		return new BlockStateContainer(this, new IProperty[] {CHECK_DECAY, DECAYABLE});
		
	}
	
	@Override
	public void registerModels() {
		
		Main.proxy.registerItemRenderer(Item.getItemFromBlock(this), 0, "inventory");
	
	}

}

 

I think it has to do with whether you have "fancy" graphics setting on perhaps. The shouldSideBeRendered() method controls this, but you don't override it. So I think you have "fast" graphics on, but you have overridden the other stuff related to graphics level such as isOpaqueCube() and getBlockRenderLayer().

 

Basically you have mixed fancy and fast graphics. You need to override the shouldSideBeRendered() method.

No, I have fancy graphics, and overriding it didnt really do anything either :\

Ugh, I find this to be quite ugly

Don't override isOpaqueCube, getBlockLayer, or shouldSideBeRendered.

Don't forget to call super() in your constructor.

 

Edited March 7, 20187 yr by Draco18s

all it did was make them solid, like leaves on fast