Official Everybody Edits Forums

Latif

Member

From: The Netherlands

Joined: 2015-03-13

Posts: 1,206

[C# Tutorial] How to use InitParse - get all blocks in a world

I decided to make my own tutorial about using InitParse, because I noticed there aren't really other tutorials except Ninjasupeatsninja's one.

So let me start.

InitParse is a class written by Processor. The class only has one single method to parse the world data you receive from the "init" message (or "reset", I will explain later). That explains why it's called InitParse. The method returns an array of DataChunk objects. The DataChunk object (part of the class) can store all properties of a block. So you basically receive an array of all blocks in a world.

Step 1: InitParse class

▼View

Simply add a new class to your project and copy paste the code in InitParse.cs from the GitHub page.

Step 2: Block class

▼View

Add another class to your project. This class it pretty simple. It only has two properties to store the block id and some arguments like coin door value, or sign text etc.

public class Block
{
    public int Id { get; set; }
    public object[] Args { get; set; }

    public Block(int Id, params object[] Args)
    {
        this.Id = Id;
        this.Args = Args;
    }
}

Step 3: Three dimensional array

▼View

In case you don't know what multidimensional arrays are, here's a helpful article about 2D arrays.

To store blocks in a world we use a three dimensional array. The first dimension is used for the layer, the second one for the x position, and the third one for the y position.

This is actually a really simple step, because the only thing you have to do is adding a public three dimensional block array:

public Block[,,] Blocks;

This uses the class you created in step 2. The two commas between the brackets mean it's three dimensional. So to get an element from the array you have to do Blocks[layer, x, y].

Step 4: Parse world data

▼View

Now we're finally going to use the InitParse class. As I said in the beginning, the parse method from the InitParse class parses the data you receive from the "init" message. So when your application receives the "init" message, you have to use the parse method to return an array of all blocks in the world:

switch (e.Type)
{
    case "init":
        //The three dimensional block array from step 3 needs a length, because it is null now.
        //The length of the first dimension (layer) should be 2, because there are two layers: 0 and 1.
        //Note that 0 counts too for the length. The second and third dimension should be the world size which is m.GetInt(18) and m.GetInt(19).
        Blocks = new Block[2, m.GetInt(18), m.GetInt(19)];

        //If the block id is 0 it's empty. So you should initialize that.
        for (int x = 0; x < m.GetInt(18); x++)
        {
            for (int y = 0; y < m.GetInt(19); y++)
            {
                Blocks[0, x, y] = new Block(0);
                Blocks[1, x, y] = new Block(0);
            }
        }

        //Parse method
        var chunks = InitParsing.Parse(m);

        //Loop through all blocks and put them in the three dimensional block array
        foreach (var c in chunks)
        {
            foreach (var pos in c.Locations)
            {
                Blocks[c.Layer, pos.X, pos.Y] = new Block(Convert.ToInt32(c.Type), c.Args);
            }
        }
        break;
}

Step 5: Updating the array

▼View

So everything works now. The only thing we haven't done yet is updating the array when someone has placed/removed a block.

The bot receives a message if someone placed/removed a block. So you can update the array if that happens:

string[] blockTypes = { "b", "bc", "br", "bs", "lb", "pt", "ts", "wp", "bn" };
if (blockTypes.Contains(m.Type))
{
    if (blockTypes.Contains(m.Type))
    {
        List<object> args = new List<object>();
        switch (m.Type)
        {
            case "b":
                Blocks[m.GetInt(0), m.GetInt(1), m.GetInt(2)].Id = m.GetInt(3);
                break;
            case "br":
                Blocks[m.GetInt(4), m.GetInt(0), m.GetInt(1)].Id = m.GetInt(2);
                Blocks[m.GetInt(4), m.GetInt(0), m.GetInt(1)].Args = new object[] { m[3] };
                break;
            default:
                Blocks[0, m.GetInt(0), m.GetInt(1)].Id = m.GetInt(2);
                for (uint i = 3; i < m.Count - 1; i++) args.Add(m[i]);
                Blocks[0, m.GetInt(0), m.GetInt(1)].Args = args.ToArray();
                break;
        }
    }
}

Credits to Tomahawk for making it shorter

Step 6: Loading the world

▼View

When you load your world (/loadlevel), your bot will receive the "reset" message. You can use InitParse in the "reset" message too because the world needs to be restored from the last save, so add a new case in the switch for "reset" and put the exact same code from init in the reset case.

Now you are done! Here's a small explanation how to use the block array:

Using the array

▼View

If you want to get the block id from a specific position in your world you can do this:

int id = Blocks[1, 40, 23].Id;

This line of code gets the block id from (40, 23) in the background layer. If there's no block at that position, it will return 0.

Let me know if you need any help, or if you have some feedback for the tutorial.

Tomahawk

Forum Mod

From: UK

Joined: 2015-02-18

Posts: 2,847

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

Why are you using null for an empty space? There is a block there with ID 0; you're just making life harder for yourself.

Also you can compact the code in Step 5 by checking the message type against an array containing all of the block types. It'll be something similar to the code in this post.

---

One bot to rule them all, one bot to find them. One bot to bring them all... and with this cliché blind them.

Latif

Member

From: The Netherlands

Joined: 2015-03-13

Posts: 1,206

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

Why are you using null for an empty space? There is a block there with ID 0; you're just making life harder for yourself.

You're right. I just changed it because I also realized it isn't really a good idea. It's a reference type so it's null by default. ¯\_(ツ)_/¯

Also you can compact the code in Step 5 by checking the message type against an array containing all of the block types. It'll be something similar to the code in this post.

I knew there was a shorter way to do that. I just didn't know how I could do it. The "br" message also confused me a lot, but I see you just added a case for that. Thanks anyway, I changed it with credits to you.

Tomahawk

Forum Mod

From: UK

Joined: 2015-02-18

Posts: 2,847

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

Note to OP and anyone else updating their mapdata in realtime: you gotta listen for "bn" as well, when an NPC gets placed.

---

One bot to rule them all, one bot to find them. One bot to bring them all... and with this cliché blind them.

Latif

Member

From: The Netherlands

Joined: 2015-03-13

Posts: 1,206

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

Note to OP and anyone else updating their mapdata in realtime: you gotta listen for "bn" as well, when an NPC gets placed.

Nice catch, it used to be there in my old code, just forgot that yours was made before the npc update.

I've added the "bn" message to the array, thanks.

Tomahawk

Forum Mod

From: UK

Joined: 2015-02-18

Posts: 2,847

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

If you want, you can add another int to the Block class and have it start collecting the ID of the player who places each block.

Just make sure you default it to -1 or something, since 0 is a valid user ID.

Btw OP, you don’t need that initialisation loop in the deserialiser class, for the same reason - the default value of an int is already 0.

---

One bot to rule them all, one bot to find them. One bot to bring them all... and with this cliché blind them.

Gosha

Member

From: Russia

Joined: 2015-03-15

Posts: 6,211

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

Step 5: Updating the array

repeating

blockTypes.Contains(m.Type)

vaishnavi

New Member

Joined: 2019-03-07

Posts: 3

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

Excellent information here. It was useful for me. Thank you!

ILikeTofuuJoe

Member

From: Obvervable Universe

Joined: 2018-06-04

Posts: 1,770

Website

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

Excellent information here. It was useful for me. Thank you!

Just woot ok

---

~meow~
Posting Goal: 2000
#Joe Griffin

Thanks HG for the signature and avatar!!!

Latif

Member

From: The Netherlands

Joined: 2015-03-13

Posts: 1,206

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

I should actually fix the flaws in this.

Excellent information here. It was useful for me. Thank you!

That's nice to hear. Glad it was helpful for you.

Just woot ok

This post was not needed.

vaishnavi

New Member

Joined: 2019-03-07

Posts: 3

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

Excellent topic!

Blackmask

Member

From: France

Joined: 2016-06-27

Posts: 199

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

Thank you for this very helpful tutorial, Latif ! However when I try to get a block id from a world I've just entered in it returns me 0 whereas when I start putting random blocks it does return me the correct id. I've put the code from Step 4 in the (if m.Type == "init") block though :/

I've tried to make it so it is a switch like step 4 but it doesn't seem to resolve anything at all. Does anybody have some idea on what I've done wrong ? Thank you.

Gosha

Member

From: Russia

Joined: 2015-03-15

Posts: 6,211

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

you can use this

▼Hidden text

using System;
using System.Collections.Generic;
using System.Drawing;
using PlayerIOClient;

namespace Bot_Example
{
    public class InitParse
    {
        public static DataChunk[] Parse(Message m)
        {
            if (m == null) throw new ArgumentNullException(nameof(m));
            if (m.Type != "init" && m.Type != "reset") throw new ArgumentException("Invalid message type.", nameof(m));

            var p = 0u;
            var data = new Stack<object>();
            while (m[p] as string != "ws") { ++p; }
            while (m[p] as string != "we") { data.Push(m[++p]); }
            var chunks = new List<DataChunk>();
            while (data.Count > 0)
            {
                var args = new Stack<object>();
                while (!(data.Peek() is byte[]))
                    args.Push(data.Pop());

                var ys = (byte[])data.Pop();
                var xs = (byte[])data.Pop();
                var layer = (int)data.Pop();
                var type = (uint)data.Pop();

                chunks.Add(new DataChunk(layer, type, xs, ys, args.ToArray()));
            }

            return chunks.ToArray();
        }
    }
    public class DataChunk
    {
        public int Layer { get; set; }
        public uint Type { get; set; }
        public Point[] Locations { get; set; }
        public object[] Args { get; set; }

        public DataChunk(int layer, uint type, byte[] xs, byte[] ys, object[] args)
        {
            Layer = layer;
            Type = type;
            Args = args;
            Locations = GetLocations(xs, ys);
        }

        private static Point[] GetLocations(byte[] xs, byte[] ys)
        {
            var points = new List<Point>();
            for (var i = 0; i < xs.Length; i += 2) points.Add(new Point((xs[i] << 8) | xs[i + 1], (ys[i] << 8) | ys[i + 1]));
            return points.ToArray();
        }
    }
    public class Point
    {
        public int X { get; set; }
        public int Y { get; set; }

        public Point(int x, int y)
        {
            X = x;
            Y = y;
        }
    }
}

Blackmask

Member

From: France

Joined: 2016-06-27

Posts: 199

Re: [C# Tutorial] How to use InitParse - get all blocks in a world

you can use this

▼Hidden text

using System;
using System.Collections.Generic;
using System.Drawing;
using PlayerIOClient;

namespace Bot_Example
{
    public class InitParse
    {
        public static DataChunk[] Parse(Message m)
        {
            if (m == null) throw new ArgumentNullException(nameof(m));
            if (m.Type != "init" && m.Type != "reset") throw new ArgumentException("Invalid message type.", nameof(m));

            var p = 0u;
            var data = new Stack<object>();
            while (m[p] as string != "ws") { ++p; }
            while (m[p] as string != "we") { data.Push(m[++p]); }
            var chunks = new List<DataChunk>();
            while (data.Count > 0)
            {
                var args = new Stack<object>();
                while (!(data.Peek() is byte[]))
                    args.Push(data.Pop());

                var ys = (byte[])data.Pop();
                var xs = (byte[])data.Pop();
                var layer = (int)data.Pop();
                var type = (uint)data.Pop();

                chunks.Add(new DataChunk(layer, type, xs, ys, args.ToArray()));
            }

            return chunks.ToArray();
        }
    }
    public class DataChunk
    {
        public int Layer { get; set; }
        public uint Type { get; set; }
        public Point[] Locations { get; set; }
        public object[] Args { get; set; }

        public DataChunk(int layer, uint type, byte[] xs, byte[] ys, object[] args)
        {
            Layer = layer;
            Type = type;
            Args = args;
            Locations = GetLocations(xs, ys);
        }

        private static Point[] GetLocations(byte[] xs, byte[] ys)
        {
            var points = new List<Point>();
            for (var i = 0; i < xs.Length; i += 2) points.Add(new Point((xs[i] << 8) | xs[i + 1], (ys[i] << 8) | ys[i + 1]));
            return points.ToArray();
        }
    }
    public class Point
    {
        public int X { get; set; }
        public int Y { get; set; }

        public Point(int x, int y)
        {
            X = x;
            Y = y;
        }
    }
}

Damn, it's working now . Thank you