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[1.7.10] Making a tool have special effects on certain blocks

Posted March 21, 20169 yr

So I'm making a mod, and I want a tool that, when mining certain blocks, has the block drop something different (not all blocks, just certain ones). For example, mining block A may drop block A, but mining block B will make it drop item C or block D. Kind of like Twilight Forest's fiery pick, except only for a few specific blocks (not anything with a smelting recipe).

How would I go about doing this? Logically I'd go about doing something to the tool's onBlockDestroyed() method, but I don't know exactly what to do about it. And this is not something that I can easily search up modding tutorials for as it is not something commonly attempted. And, if one of the blocks I want to check for is stone, would this code be appropriate for checking if the block is stone?

if(block.getIdFromBlock(block) == block.getIdFromBlock(Blocks.stone))
{
//drop a different block here
}

And finally, what would be the code for spawning a dropped item? Not sure if I need it here or not, but I think it may help in the future.

Quote

March 21, 20169 yr

Author

How do I use a HarvestDropsEvent?

Do I create a separate class to handle this, or can I put it in the code for my mod pickaxe class?

Quote

March 21, 20169 yr

Author

Thanks, I was able to use the harvesting event to get a block to drop something additional when a specific tool is used.

I guess I could look this up but since I'm here, how to I get the event to remove a drop?

Quote

March 21, 20169 yr

event.drops.clear()

It's an array list, use it like one.

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Exception: If you do not understand Java, I WILL NOT HELP YOU and your thread will get locked.

DO NOT PM ME WITH PROBLEMS. No help will be given.

Quote

March 21, 20169 yr

Author

Thanks, this will really help.

Quote

March 21, 20169 yr

Author

Darn it, I've run into another problem.

So I created a pickaxe that when mining stone drops my custom block, and has a 25% chance to set the player on fire when mining a block. Code for harvest event below:

(Note: some of it is obfuscated with xxxx to keep names a secret)

@SubscribeEvent
public void xxxxPick(HarvestDropsEvent event)
{
	ItemStack theTool = event.harvester.getCurrentEquippedItem();
	if(theTool != null)
	{
		if(theTool.getItem() == ToolManager.xxxxPickaxe)
		{	
			if(random.nextInt(4) == 0)
			{
				event.harvester.setFire(5);
			}

			if(event.block != null)
			{
				if(event.block == Blocks.stone)
				{
					event.drops.clear();
					event.drops.add(new ItemStack(Item.getItemFromBlock(myBlocksClass.myCustomStone)));
				}
			}				
		}
	}

However, occasionally I get a crash report, stating a NullPointerException has occured doing my custom pick event. This really confuses me since I checked to see if both the block and the tool are not null before using them. Example below:

// Hi. I'm Minecraft, and I'm a crashaholic.

Time: 3/21/16 7:12 PM

Description: Exception ticking world

java.lang.NullPointerException: Exception ticking world

at net.xxxxxx.events.HarvestingEvents.xxxxPick(HarvestingEvents.java:38)

at cpw.mods.fml.common.eventhandler.ASMEventHandler_6_HarvestingEvents_xxxxPick_HarvestDropsEvent.invoke(.dynamic)

at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:54)

at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:140)

at net.minecraftforge.event.ForgeEventFactory.fireBlockHarvesting(ForgeEventFactory.java:162)

at net.minecraft.block.Block.dropBlockAsItemWithChance(Block.java:806)

at net.minecraft.block.Block.dropBlockAsItem(Block.java:795)

at net.minecraft.block.BlockBush.checkAndDropBlock(BlockBush.java:74)

at net.minecraft.block.BlockBush.updateTick(BlockBush.java:64)

at net.minecraft.world.WorldServer.func_147456_g(WorldServer.java:408)

at net.minecraft.world.WorldServer.tick(WorldServer.java:191)

at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:692)

at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:614)

at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:118)

at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:485)

at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:752)

A detailed walkthrough of the error, its code path and all known details is as follows:

---------------------------------------------------------------------------------------

-- Head --

Stacktrace:

at net.xxxxxxx.events.HarvestingEvents.xxxxPick(HarvestingEvents.java:38)