Hello!  I am looking to use ray tracing to find the position of the block the player is looking at.  Then, when the player right clicks the item, it summons a lightning bolt at that block's location.  I have created my own code for this, but nothing is currently working (not summoning lightning at all).  I am new to ray tracing but apparently this is not how it is done (question mark?).  I am just looking to see what I have done wrong and to build on knowledge for the future.

 

import net.minecraft.block.Block;
import net.minecraft.block.Blocks;
import net.minecraft.entity.Entity;
import net.minecraft.entity.EntityType;
import net.minecraft.entity.effect.LightningBoltEntity;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.stats.Stats;
import net.minecraft.util.ActionResult;
import net.minecraft.util.ActionResultType;
import net.minecraft.util.Hand;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.math.BlockRayTraceResult;
import net.minecraft.util.math.EntityRayTraceResult;
import net.minecraft.util.math.MathHelper;
import net.minecraft.util.math.RayTraceContext;
import net.minecraft.util.math.RayTraceContext.FluidMode;
import net.minecraft.util.math.RayTraceResult;
import net.minecraft.util.math.vector.Vector3d;
import net.minecraft.world.World;
import net.minecraft.world.server.ServerWorld;

public class LightningWandItem extends Item
{
	public LightningWandItem(Properties properties) 
	{
		super(properties);
	}

	private RayTraceResult rayTrace(World world, PlayerEntity player)
	{
		float rotationPitch = player.getYHeadRot();
		float rotationYaw = player.xRot;
		Vector3d eyePosition = player.getEyePosition(1.0F);
		
		// look vector
		float f2 = MathHelper.cos(-rotationYaw * ((float)Math.PI / 180F) - (float)Math.PI);
		float f3 = MathHelper.sin(-rotationYaw * ((float)Math.PI / 180F) - (float)Math.PI);
		float f4 = -MathHelper.cos(-rotationPitch * ((float)Math.PI / 180F));
		float f5 = MathHelper.sin(-rotationPitch * ((float)Math.PI / 180F));
		float f6 = f3 * f4;
		float f7 = f2 * f4;
		double rayTraceDistance = 54;
		
		// from start pos, add look vector multiplied by rayTraceDistance
		Vector3d endPosition = eyePosition.add((double)f6 * rayTraceDistance, (double)f5 * rayTraceDistance, (double)f7 * rayTraceDistance);
		return world.clip(new RayTraceContext(eyePosition, endPosition, RayTraceContext.BlockMode.OUTLINE, FluidMode.NONE, player));
	}
	
	public ActionResult<ItemStack> onItemRightClick(World worldIn, PlayerEntity playerIn, Hand handIn) 
	{
		if(!worldIn.isClientSide)
		{
			ItemStack stack = playerIn.getItemInHand(handIn);
			RayTraceResult result = this.rayTrace(worldIn, playerIn);
			if(result instanceof BlockRayTraceResult)
			{
				BlockPos pos = ((BlockRayTraceResult) result).getBlockPos();
				Block block = worldIn.getBlockState(pos).getBlock();
				if(block != Blocks.AIR)
				{
					if(worldIn instanceof ServerWorld)
					{
						LightningBoltEntity lightningEntity = new LightningBoltEntity(EntityType.LIGHTNING_BOLT, worldIn);
						lightningEntity.setPos(pos.getX(), pos.getY(), pos.getZ());
						
						playerIn.awardStat(Stats.ITEM_USED.get(this));
						if (!playerIn.abilities.mayfly) {
							stack.hurtAndBreak(1, playerIn, (p_219998_1_) -> {
								p_219998_1_.broadcastBreakEvent(handIn);
							});
						}	
					}
				}
				return new ActionResult<ItemStack>(ActionResultType.SUCCESS, stack);
				
			} else if(result instanceof EntityRayTraceResult)
			{
				Entity entity = ((EntityRayTraceResult) result).getEntity();
				if(worldIn instanceof ServerWorld)
				{
					Vector3d entityPos = entity.position();
					LightningBoltEntity lightningEntity = new LightningBoltEntity(EntityType.LIGHTNING_BOLT, worldIn);
					lightningEntity.setPos(entityPos.x(), entityPos.y(), entityPos.z());
				
					playerIn.awardStat(Stats.ITEM_USED.get(this));
					if (!playerIn.abilities.mayfly) {
						stack.hurtAndBreak(1, playerIn, (p_219998_1_) -> {
							p_219998_1_.broadcastBreakEvent(handIn);
						});
					}
				}
				return new ActionResult<ItemStack>(ActionResultType.SUCCESS, stack);
			}
			
			playerIn.getItemInHand(handIn);
		}
		return super.use(worldIn, playerIn, handIn);
	}
}

 

I can't tell if you are doing ray tracing right, but there's already a method in Entity called getLookVec or something similar. Secondly, you've create the lightning entities but had never add them to the world. Use World#addEntity

I do now realize that I wasn't using the correct method.  I have changed "onItemRightClick" to "use" and now the item does function.  It functions because I also added the entity to the world, as you had mentioned that I had not added it (oops).  Now, it does summon lightning, but only whenever I look certain ways and my ray tracing does not work well because the lightning is not summoned where I am looking.  I will try to use getLookVec (or whatever the name is) to trace instead and see how that goes.

I have changed the code so that it now overrides the method.  However, I think there are some problems with my raytracing method.  It does not properly trace where the player is looking and grabbing that block pos.