Adding Block Behavior

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Introduction

Block Behaviors are useful when you want different blocks to act in the same way, as you can attach one or more block behaviors to an arbitrary number of blocks. You may want to have a look at the existing block behaviors before implementing your own.

In this tutorial we'll create a new Behavior that we can attach to blocks to make them movable by right clicking them.

Setting up

A development workspace is required. Additionally you will need the assets (blocktype, texture and lang file). You can either create your one owns or use those pre-made ones: Moving - No CS File.zip

Creating the behavior

So first of all we need to create the behavior itself, which is a class extending BlockBehavior

class Moving : BlockBehavior
{
    public Moving(Block block) : base(block)
    {
        
    } 
}

This class provides several methods we can override. When you use Visual Studio you can find a full list of a methods by hovering with the mouse of "BlockBehavior" and pressing "F12".


The method bool OnPlayerInteract(IWorldAccessor world, IPlayer byPlayer, BlockSelection blockSel, ref EnumHandling handling) looks to be ideal for our purpose.

What should it do?

  1. Calculate the new position of the block depending on the face the player is looking at
  2. Check if the block can be placed at this position
  3. Remove the original block
  4. Place the new block using the previously calculated position
    public override bool OnPlayerInteract(IWorldAccessor world, IPlayer byPlayer, BlockSelection blockSel, ref EnumHandling handling)
    {
        // Find the target position
        BlockPos pos = blockSel.Position.AddCopy(blockSel.Face.GetOpposite());

        // Can we place the block there?
        if (world.BlockAccessor.GetBlock(pos).IsReplacableBy(block))
        {
            // Remove the block at the current position and place it at the target position
            world.BlockAccessor.SetBlock(0, blockSel.Position);
            world.BlockAccessor.SetBlock(block.BlockId, pos);
        }

        // Notify the game engine other block behaviors that we handled the players interaction with the block.
        // If we would not set the handling field the player would still be able to place blocks if he has them in hands.
        handling = EnumHandling.PreventDefault;
        return true;
    }

Register

In order the register the BlockBehavior we need to create a mod class, override Start(ICoreAPI) and register it with the given name:

    public class MovingBlocks : ModBase
    {

        public override void Start(ICoreAPI api)
        {
            base.Start(api);
            api.RegisterBlockBehaviorClass("Moving", typeof(Moving));
        }

    }

Distribution

In order to finish everything, open the modtools and type in pack <your mod id>. Now you can take the zip file and share it with other people. You can download the example mod here.

Testing

Advanced Behavior

Our behavior is still rather simple, but there are a lot more possibilities. A behavior can have special properties, which can be defined by the blocktype itself.

Example

The behavior liquid supports some special properties as shown in this example of the water blocktype:

	behaviors: [
		{
			name: "FiniteSpreadingLiquid", 
			properties:
			{
				spreadDelay: 150, 
				liquidCollisionSound: "hotmetal", 
				sourceReplacementCode: "obsidian", 
				flowingReplacementCode: "basalt"
			}
		}
	],

Parsing properties

In order to take care of special properties there is a method called Initialize(JsonObject). Each blocktype creates a new instance of the behavior, so the method can be used to parse the properties.

So what kind of properties could we add?

  • push distance
  • pull block if player is sneaking

First of all, we need to override the method in our block behavior class ...

        public override void Initialize(JsonObject properties)
        {
            base.Initialize(properties);
        }

Additionally we need to add two fields, one for the distance and another one if the player should pull the block while sneaking ...

        public int distance = 1;
        public bool pull = false;

Now we can parse the two properties like so:

        distance = properties["distance"].AsInt(1);
        pull = properties["pull"].AsBool(false);

The next thing we need to change is the interact method itself, so that it takes care of the distance and the pull properties ...

        public override bool OnPlayerInteract(IWorldAccessor world, IPlayer byPlayer, BlockSelection blockSel, ref EnumHandling handling)
        {
            BlockPos pos = blockSel.Position.AddCopy(pull && byPlayer.WorldData.EntityControls.Sneak ? blockSel.Face : blockSel.Face.GetOpposite(), distance);
            if (world.BlockAccessor.GetBlock(pos).IsReplacableBy(block))
            {
                world.BlockAccessor.SetBlock(0, blockSel.Position);
                world.BlockAccessor.SetBlock(block.BlockId, pos);
            }
            handling = EnumHandling.PreventDefault;
            return true;
        }

Adding another block

Let's create another block using this behavior, but this time we will configure some additional properties ...

	behaviors: [
		{
			name: "Moving",
			properties: {
				"distance": 2,
				"pull": true
			}
		}
	],

The block will be pushed two blocks instead of one and the player can pull it by sneaking while right clicking.

You can download the complete mod here.



Vintage Story: Modding
Basics Mod Types | Asset System | Textures | Items | Recipes | Blocks | Model Creator | Release
Advanced Setup(Windows,Linux) | Items | Blocks | Item-Block interractions | Block Behavior | Block Entity | Particles | World Access
Worldgen Terrain | Ores | Trees | Worldgen API
Rendering Shaders and Renderers
Property Overview Item | Block