Modding:Advanced Items

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This code mod tutorial requires a development environment. If you do not have one, please read and complete the Setting up your Development Environment page. It is also highly recommended to have read and completed the Basic Item tutorial.

Creating a Tunnel Pickaxe

In this tutorial will we create a item with more advanced functionality: A pickaxe which allows you to dig a 3x3 tunnel by mining just one block.

Item Assets

Similar to the Basic Item, we need to create our item's assets, including an itemtype, texture and a lang file. Those assets are pretty straight forward and you can download them here. Extract the file to your mods folder, and you are ready to start programming.

There is only one new property in your itemtype json, class. This property tells our new item to be controlled by a certain C# class.

	class: "tunnler",

We will create this class to give the item the desired functionality.

The Item Class

Creating our item requires a couple new *.cs files in our project.

If you have read the Advanced Blocks Tutorial already, this should be familar to you.

The Mod System

In order to register your item class, we need to create a mod, which is a class extending ModSystem:

public class TunnlerMod : ModSystem
{
    
}

By overriding the Start(ICoreAPI) method, we can register our class. The RegisterItemClass function has two parameters: the first is our item class ID, noteably this is how we link to this class in our itemtype json files. Ensure that this is identical to the class we specified in our earlier asset file. The second parameter is the type of our item class.

public class TunnlerMod : ModSystem
{
    public override void Start(ICoreAPI api)
    {
        base.Start(api);
        api.RegisterItemClass("tunnler", typeof(TunnlerItem));
    }
}

This should be marked as a syntax error because there is no TunnlerItem class yet.

The Item Class

When naming item scripts, it is recommended to name them in the format "{Name}Item". In the case of the tunnler pickaxe, we shall name our script TunnlerItem.cs. Any itemclass has to extend Item, giving it the functionality we need to access:

public class TunnlerItem : Item
{

}

This should solve all syntax errors.

So what should our tool do? Once the player mines a block with this tool every block around it should be mined as well.

As always, we can refer to the item api docs to find a function we can use. Although the item class itself does not contain an appropriate function, we can also check the CollectibleObject api docs, which the item class extends from.

In our specific case, we can override the method bool OnBlockBrokenWith(IWorldAccessor world, Entity byEntity, ItemSlot itemslot, BlockSelection blockSel, float dropQuantityMultiplier = 1).

We need to be aware of the facing (which side the player is focusing) and if the player is in creative or survival mode (whether items should be dropped or not). Before we are going to override OnBlockBrokenWith we should create a method which destroys all blocks between two block positions (min & max). It should also only drop items if the player is in survival mode:

public void DestroyBlocks(IWorldAccessor world, BlockPos min, BlockPos max, IPlayer player)
{
    BlockPos tempPos = new BlockPos();
    for (int x = min.X; x <= max.X; x++)
    {
        for (int y = min.Y; y <= max.Y; y++)
        {
            for (int z = min.Z; z <= max.Z; z++)
            {
                tempPos.Set(x, y, z);
                if (player.WorldData.CurrentGameMode == EnumGameMode.Creative)
                    world.BlockAccessor.SetBlock(0, tempPos);
                else
                    world.BlockAccessor.BreakBlock(tempPos, player);
            }
        }
    }
}

Now we can implement OnBlockBroken rather easily, by taken care of every possible axis the player could face:

public override bool OnBlockBrokenWith(IWorldAccessor world, Entity byEntity, ItemSlot itemslot, BlockSelection blockSel, float dropQuantityMultiplier = 1)
{
    if (base.OnBlockBrokenWith(world, byEntity, itemslot, blockSel))
    {
        if (byEntity is EntityPlayer)
        {
            IPlayer player = world.PlayerByUid((byEntity as EntityPlayer).PlayerUID);
            switch (blockSel.Face.Axis)
            {
                case EnumAxis.X:
                    destroyBlocks(world, blockSel.Position.AddCopy(0, -1, -1), blockSel.Position.AddCopy(0, 1, 1), player);
                    break;
                case EnumAxis.Y:
                    destroyBlocks(world, blockSel.Position.AddCopy(-1, 0, -1), blockSel.Position.AddCopy(1, 0, 1), player);
                    break;
                case EnumAxis.Z:
                    destroyBlocks(world, blockSel.Position.AddCopy(-1, -1, 0), blockSel.Position.AddCopy(1, 1, 0), player);
                    break;
            }
        }
        return true;
    }
    return false; 
}

---

If you have done everything right, your file should look similar to this:

using Vintagestory.API.Common;
using Vintagestory.API.Common.Entities;
using Vintagestory.API.MathTools;

namespace ExampleMods
{
    public class TunnlerMod : ModSystem
    {

public override void Start(ICoreAPI api)
        {
            base.Start(api);
            api.RegisterItemClass("tunnler", typeof(TunnlerItem));
        }

}

public class TunnlerItem : Item
    {

public void DestroyBlocks(IWorldAccessor world, BlockPos min, BlockPos max, IPlayer player)
        {
            BlockPos tempPos = new BlockPos();
            for (int x = min.X; x <= max.X; x++)
            {
                for (int y = min.Y; y <= max.Y; y++)
                {
                    for (int z = min.Z; z <= max.Z; z++)
                    {
                        tempPos.Set(x, y, z);
                        if (player.WorldData.CurrentGameMode == EnumGameMode.Creative)
                            world.BlockAccessor.SetBlock(0, tempPos);
                        else
                            world.BlockAccessor.BreakBlock(tempPos, player);
                    }
                }
            }
        }

public override bool OnBlockBrokenWith(IWorldAccessor world, Entity byEntity, ItemSlot itemslot, BlockSelection blockSel, float dropQuantityMultiplier = 1)
        {
            if (base.OnBlockBrokenWith(world, byEntity, itemslot, blockSel))
            {
                if (byEntity is EntityPlayer)
                {
                    IPlayer player = world.PlayerByUid((byEntity as EntityPlayer).PlayerUID);
                    switch (blockSel.Face.Axis)
                    {
                        case EnumAxis.X:
                            destroyBlocks(world, blockSel.Position.AddCopy(0, -1, -1), blockSel.Position.AddCopy(0, 1, 1), player);
                            break;
                        case EnumAxis.Y:
                            destroyBlocks(world, blockSel.Position.AddCopy(-1, 0, -1), blockSel.Position.AddCopy(1, 0, 1), player);
                            break;
                        case EnumAxis.Z:
                            destroyBlocks(world, blockSel.Position.AddCopy(-1, -1, 0), blockSel.Position.AddCopy(1, 1, 0), player);
                            break;
                    }
                }
                return true;
            }
            return false; 
        }

}
}

You can also download the file directly: Tunnler.cs.

Testing

This is how it looks ingame:

Distribution

Using the new Mod Template

If using the mod template setup, follow the instructions on Setting up your Development Environment to pack and distribute your mod.

Using the (old) Modtools

If using the modtools program, open the modtools and type in pack <your mod id>. Now you can take the zip file and share it with other people. It will work in the same way as ordinary mods, you can install it by copying it into the mods folder.

Mod Download

Here is my version:

• for VS v1.9: Tunnler_vs1.9_v1.0.0.zip
• for VS v1.8: Tunnler.zip

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