TintedTreeGenerator.java

package com.yolp900.itsjustacharm.common.world;

import com.yolp900.itsjustacharm.common.blocks.ModBlocks;
import net.minecraft.block.Block;
import net.minecraft.block.state.IBlockState;
import net.minecraft.util.EnumFacing;
import net.minecraft.util.math.BlockPos;
import net.minecraft.world.World;
import net.minecraft.world.chunk.IChunkGenerator;
import net.minecraft.world.chunk.IChunkProvider;
import net.minecraftforge.fml.common.IWorldGenerator;

import java.util.Random;

public class TintedTreeGenerator implements IWorldGenerator {

	public final int minTreeHeight;
	public final int treeHeightRange;
	public final IBlockState log;
	public final IBlockState leaves;

	private Random rand;

	public TintedTreeGenerator() {
		this(3, 3, ModBlocks.TintedLog.getDefaultState(), ModBlocks.TintedLeaves.getDefaultState());
	}

	public TintedTreeGenerator(int treeHeight, int treeRange, IBlockState log, IBlockState leaves) {
		this.minTreeHeight = treeHeight;
		this.treeHeightRange = treeRange;
		this.log = log;
		this.leaves = leaves;
	}

	@Override
	public void generate(Random random, int chunkX, int chunkZ, World world, IChunkGenerator chunkGenerator, IChunkProvider chunkProvider) {

	}

	public void generateTree(Random random, World world, BlockPos pos) {
		int height = random.nextInt(this.treeHeightRange) + this.minTreeHeight;
		int yPos = pos.getY();

		if(yPos >= 1 && yPos + height + 1 <= 256) {
			IBlockState state = world.getBlockState(pos.down());
			Block soil = state.getBlock();
			boolean isSoil = soil.canSustainPlant(state, world, pos.down(), EnumFacing.UP, ModBlocks.TintedSapling);

			if (isSoil) {
				this.rand = random;
				soil.onPlantGrow(state, world, pos.down(), pos);
				placeCanopy(world, pos, height);
				placeTrunk(world, pos, height);
			}
		}
	}

	private void placeCanopy(World world, BlockPos pos, int height) {
		pos = pos.up(height + 2);

		setLeaves(world, pos, LeafRarity.RARE);

		pos = pos.down();

		for (int i = -1; i < 2; i++) {
			for (int j = -1; j < 2; j++) {
				setLeaves(world, pos.add(i, 0, j), LeafRarity.ALWAYS);
			}
		}

		pos = pos.down();

		for (int i = -1; i < 2; i++) {
			for (int j = -1; j < 2; j++) {
				if (!(i == 0 && j == 0)){
					setLeaves(world, pos.add(i, 0, j), LeafRarity.ALWAYS);
				}
			}
		}

		setLeaves(world, pos.add(-2, 0, 0), LeafRarity.COMMON);
		setLeaves(world, pos.add(0, 0, -2), LeafRarity.COMMON);
		setLeaves(world, pos.add(2, 0, 0), LeafRarity.COMMON);
		setLeaves(world, pos.add(0, 0, 2), LeafRarity.COMMON);

		pos = pos.down();

		for (int i = -1; i < 2; i++) {
			for (int j = -1; j < 2; j++) {
				if (!(i == 0 && j == 0)){
					setLeaves(world, pos.add(i, 0, j), LeafRarity.ALWAYS);
				}
			}
		}

		setLeaves(world, pos.add(-2, 0, 0), LeafRarity.COMMON);
		setLeaves(world, pos.add(0, 0, -2), LeafRarity.COMMON);
		setLeaves(world, pos.add(2, 0, 0), LeafRarity.COMMON);
		setLeaves(world, pos.add(0, 0, 2), LeafRarity.COMMON);

		pos = pos.down();

		setLeaves(world, pos.add(-1, 0, 0), LeafRarity.COMMON);
		setLeaves(world, pos.add(0, 0, -1), LeafRarity.COMMON);
		setLeaves(world, pos.add(1, 0, 0), LeafRarity.COMMON);
		setLeaves(world, pos.add(0, 0, 1), LeafRarity.COMMON);

	}

	private void placeTrunk(World world, BlockPos pos, int height) {
		while(height >= 0) {
			IBlockState state = world.getBlockState(pos);
			Block block = state.getBlock();
			if(block.isAir(state, world, pos) || block.isReplaceable(world, pos) || block.isLeaves(state, world, pos)) {
				setLog(world, pos);
			}

			pos = pos.up();
			height--;
		}
	}

	private void setLog(World world, BlockPos pos) {
		setBlockAndMetadata(world, pos, log);
	}

	private void setLeaves(World world, BlockPos pos, LeafRarity rarity) {
		if (rarity == LeafRarity.ALWAYS) {
			setBlockAndMetadata(world, pos, leaves);
		} else if (rarity == LeafRarity.COMMON) {
			if (rand.nextInt(10) < 7) setBlockAndMetadata(world, pos, leaves);
		} else if (rarity == LeafRarity.RARE) {
			if (rand.nextInt(10) < 3) setBlockAndMetadata(world, pos, leaves);
		}
	}

	private void setBlockAndMetadata(World world, BlockPos pos, IBlockState stateNew) {
		IBlockState state = world.getBlockState(pos);
		Block block = state.getBlock();
		if(block.isAir(state, world, pos) || block.canPlaceBlockAt(world, pos) || world.getBlockState(pos) == leaves) {
			world.setBlockState(pos, stateNew, 2);
		}
	}

	private enum LeafRarity {
		ALWAYS,
		COMMON,
		RARE
	}

}