Adding Custom Drops to Vanilla Mobs

For this tutorial I will be removing the normal pig drops, and replacing them with a gold ingot (because I can). Let’s get to it, shall we?

First I’ll clarify we’ll be fiddling with forge’s event listeners, and these are great stuff to “modify” vanilla Minecraft, by intercepting vanilla events, hence the name. For this time, we will use the LivingDropsEvent event. If you want to check out other events, check them out here. It’s not mine, so kudos to anyone who made that.

Okay, let’s make the event handler class. Usually, for organization purposes I place this class in another seperate package, called “handler” (duh). I will be naming my class “MobDropsHandler”.

public class MobDropsHandler
{
    @SubscribeEvent
    public void onMobDrops(LivingDropsEvent event)
    {
        if (event.entity instanceof EntityPig)
        {
            event.drops.clear();

            ItemStack stack = new ItemStack(Items.gold_ingot);
            EntityItem drop = new EntityItem(event.entity.worldObj, event.entity.posX, event.entity.posY, event.entity.posZ, stack);

            event.drops.add(drop);
        }
    }
}

Alright, simple as that. Note the @SubscribeEvent annotation. All event handler methods MUST have that, or forge won’t recognize it. The method name can be anything you want, I just used onMobDrops for clarity.

This event has fields for us to use, one of them being the entity, and another being the EntityItem list of the itemstacks dropped. We’ll make use of both. First we check if the entity is a pig, because that’s what we want. If it IS a pig, we then clear it’s default drops. You can omit the clear() method if you don’t want this. After that, we create an EntityItem of the ItemStack we want to output, with the world and position from the entity. Lastly, we add our custom EntityItem back into the drops ArrayList.

We’re done with this class! All we need to do is register this in your main mod class. In your loading method (preInit, init, or postInit all works), add the following line to register our event handler:

MinecraftForge.EVENT_BUS.register(new MobDropsHandler());

And we’re done! Go ahead and try it out.