Checking the drop chance of a mob

[SecondAmendment]

Is there a way to check the drop chance of an item a mob is holding?

[Choonster]

On 16/02/2017 at 1:37 PM, Choonster said:

EntityLiving#inventoryHandsDropChances and EntityLiving#inventoryArmorDropChances store the drop chances for the entity's held items and armour respectively. These fields are both protected, so you'll need to use reflection to access them.

 

 

Edited February 19, 2017 by Choonster

[SecondAmendment]

Damn it, I hate using Reflection

[SecondAmendment]

Hmmmm... Im having trouble getting the field. the crash report says it cannot find it. What am I doing wrong?

 

	public void playerTick(PlayerTickEvent event) throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException, SecurityException
	{
		List<Entity> entities = event.player.getEntityWorld().getEntitiesWithinAABBExcludingEntity(event.player, event.player.getEntityBoundingBox().expand(5.0D, 5.0D, 5.0D));
		for(Entity entity : entities){
			if((entity instanceof EntityMob && ((EntityLivingBase) entity).getHeldItemMainhand() != null && !previousmobs.contains(entity))){
				Field dropchance = null;
				dropchance = ((EntityLiving)entity).getClass().getDeclaredField("inventoryHandsDropChances");
				dropchance.setAccessible(true);
				Object floatchance = dropchance.get(entity);
				event.player.addChatMessage(((EntityLivingBase) entity).getHeldItemMainhand().getTextComponent().appendSibling((new TextComponentString(" Drop Chance: ").appendText(Array.get(floatchance , 0).toString()))));

 

 

Crash Report: 

[11:04:45] [Server thread/ERROR]: Encountered an unexpected exception
net.minecraft.util.ReportedException: Ticking player
	at net.minecraft.network.NetworkSystem.networkTick(NetworkSystem.java:210) ~[NetworkSystem.class:?]
	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:806) ~[MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:687) ~[MinecraftServer.class:?]
	at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:156) ~[IntegratedServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:536) [MinecraftServer.class:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_65]
Caused by: java.lang.RuntimeException: java.lang.NoSuchFieldException: inventoryHandsDropChances
	at com.google.common.base.Throwables.propagate(Throwables.java:160) ~[guava-17.0.jar:?]
	at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:191) ~[EventBus.class:?]
	at net.minecraftforge.fml.common.FMLCommonHandler.onPlayerPreTick(FMLCommonHandler.java:360) ~[FMLCommonHandler.class:?]
	at net.minecraft.entity.player.EntityPlayer.onUpdate(EntityPlayer.java:215) ~[EntityPlayer.class:?]
	at net.minecraft.entity.player.EntityPlayerMP.onUpdateEntity(EntityPlayerMP.java:341) ~[EntityPlayerMP.class:?]
	at net.minecraft.network.NetHandlerPlayServer.update(NetHandlerPlayServer.java:174) ~[NetHandlerPlayServer.class:?]
	at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher$1.update(NetworkDispatcher.java:216) ~[NetworkDispatcher$1.class:?]
	at net.minecraft.network.NetworkManager.processReceivedPackets(NetworkManager.java:308) ~[NetworkManager.class:?]
	at net.minecraft.network.NetworkSystem.networkTick(NetworkSystem.java:195) ~[NetworkSystem.class:?]
	... 5 more
Caused by: java.lang.NoSuchFieldException: inventoryHandsDropChances

 

[Draco18s]

A few things:

Don't ever use reflection inside a tick or update event.  That is, the "go find this by string name" because it's expensive as hell.  Get the field once, store it in a class field for later.

Two, look at the ReflectionHelper class.  It'll make this easier.

Three, that will only work in dev, you'll need to use MCP Bot to get the SRG name so that it works when compiled, too.

[SecondAmendment]

2 minutes ago, Draco18s said:

A few things:

Don't ever use reflection inside a tick or update event.  That is, the "go find this by string name" because it's expensive as hell.  Get the field once, store it in a class field for later.

Two, look at the ReflectionHelper class.  It'll make this easier.

Three, that will only work in dev, you'll need to use MCP Bot to get the SRG name so that it works when compiled, too.

How do I do it with MC Bot in order to get the SRG name?

[Draco18s]

On the page I linked: download the fields/methods csv files. Open it in Excel or other spreadsheet program. Search for the thing you want the SRG name for. Copy the SRG name.

 

There's also an IRC interface, but I don't use it.

Edited February 19, 2017 by Draco18s

[SecondAmendment]

What would the method be called? I cant seem to find it on the spreadsheet

[Draco18s]

Well, you're looking for a field named inventoryHandsDropChances, so search the fields.csv file for "inventoryHandsDropChances"