How to Write a Client - Revision history

imported>LassiPulkkinen: Add Category:Minecraft Modern

2024-02-26T19:00:33Z

← Older revision		Revision as of 19:00, 26 February 2024
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	If your health updates come much slower than on the notchian client, make sure you are sending position updates fast enough.		If your health updates come much slower than on the notchian client, make sure you are sending position updates fast enough.

			[[Category:Minecraft Modern]]

imported>Ninjadev64: Fix typo

2022-04-07T10:56:12Z

Fix typo

← Older revision		Revision as of 10:56, 7 April 2022
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	Paraphrase (with no authentication and no encryption): send a 0x02, get a 0xFD, send a 0xCD, get a 0x01, get a 0x06. Then you'll eventually get a 0x0D, and that's when the game really begins.		Paraphrase (with no authentication and no encryption): send a 0x02, get a 0xFD, send a 0xCD, get a 0x01, get a 0x06. Then you'll eventually get a 0x0D, and that's when the game really begins.

	Paraphrase (with no authentication): send a 0x02, get a 0xFD, send a 0xFC, get a 0xFC (Then enable AES ~~encrpytion~~), get a 0x01, get a 0x06. Then you'll eventually get a 0x0D, and that's when the game really begins.		Paraphrase (with no authentication): send a 0x02, get a 0xFD, send a 0xFC, get a 0xFC (Then enable AES encryption), get a 0x01, get a 0x06. Then you'll eventually get a 0x0D, and that's when the game really begins.

	To test if this worked, connect to your localhost server with the notchian client and see if you can see your custom client appear and float in the air.		To test if this worked, connect to your localhost server with the notchian client and see if you can see your custom client appear and float in the air.

imported>U9G: updated minecraft-data link

2021-02-23T14:10:16Z

updated minecraft-data link

← Older revision		Revision as of 14:10, 23 February 2021
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	gold: 0		gold: 0

	for the following fields, see https://github.com/PrismarineJS/minecraft-data/blob/master/data/1.8/blocks.json		for the following fields, see https://github.com/PrismarineJS/minecraft-data/blob/master/data/pc/1.8/blocks.json
	Block.hardness		Block.hardness
	Block.material		Block.material

imported>Zmic: /* Parsing the messages */

2016-08-16T09:39:43Z

Parsing the messages

← Older revision		Revision as of 09:39, 16 August 2016
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	''Main article: [[Protocol]]''		''Main article: [[Protocol]]''

	~~Sorry, but you have to be able to parse ''all'' the messages. Write all the message parsing code. If you don't, your client will probably crash due to the packets being out of sync.~~		Your client must be able to ''handle'' all the messages, but not necessarily be able to parse all the data. It is possible to skip packets that you're not interested in. Since the length of the packet is transmitted at the beginning of every packet (see [[Protocol#Packet_format\|Packet Format]]), your client can simply skip the correct number of bytes to stay in sync. You ''will'' need libraries to do encryption (openssl or crypto) and compression (zlib).

	~~More accurately, your~~ client must be able to ''handle'' all the messages, but not necessarily be able to parse all the data. ~~Your~~ client can simply skip the correct number of bytes to stay in sync. ~~Many messages have a fixed length~~ and ~~can easily be skipped~~.

	== Login ==		== Login ==

imported>Pokechu22: /* Useful client "features" */ IMO we don't need this stuff; a lot of it's outdated anyways

2016-03-06T06:30:34Z

Useful client "features": IMO we don't need this stuff; a lot of it's outdated anyways

← Older revision		Revision as of 06:30, 6 March 2016
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	If your health updates come much slower than on the notchian client, make sure you are sending position updates fast enough.		If your health updates come much slower than on the notchian client, make sure you are sending position updates fast enough.

	~~== Useful client features ==~~

	* Always sneak: You can do it via the Packet 0x13. On notchian clients, crouching reduces your speed and your ability to maneuver while jumping, but the server doesn't restrict it.
	* Fly: Just change the "on-ground" flag and send the server positions in the air. As long as you don't collide with a block, the server will obey.
	* Semi-invulnerability: Don't send position updates, that causes that you'll not recieve health updates and entities will be unable to attack you.
	* Full bright (Night vision): Don't render any lights, just use an ambient term
	* Wallhack+ESP: Disable zbuffer tests for entities. This will make them appear even if they are behind walls. Also you can make some billboard texts showing position, item shown, bigger name.
	* Xray: Treat some blocks as air.
	* Nuker / Instamine: Send lots of "start digging" and "finish digging" packets to surrounding blocks. If done correctly it wil "nuke" an area really fast. Brings a lot of lag to the server. Does not work in 1.4 and next versions.
	* Torch destroy: Search for torches within 4 blocks of the user and send a digg packet for each one. They will get destroyed even if the view line is obstructed.
	* Speedhack: Just move the player faster than vanilla client
	* Cavefinder: Use front face culling and show only stone blocks in contact with air
	* More Reach: Does not work since 1.4, server checks that placed/dug block is near the player
	* ForceField: Automatically swing everyone who is within 4 block of the player, killing them if pvp is enabled.
	* No swing: Don't send swing packets. They aren't needed to dig or place blocks
	* Spider: Climb every block as if there was a ladder in front of it
	* Walk on water: Set all water blocks as solid
	* Disable fall damage: Toggle the isOnGround field in your mob's entity update each tick.
	* Sounder/PlayerFinder: finds players outside of rendering during thunderstorms by getting where lighting sound packets

imported>Gjum: add out of date notice

2015-12-19T01:58:03Z

add out of date notice

← Older revision		Revision as of 01:58, 19 December 2015
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	This tutorial is being created to document what it takes to write a stand-alone client to interact with a notchian server. The tutorial is incomplete but will be updated whenever more information is discovered.		This tutorial is being created to document what it takes to write a stand-alone client to interact with a notchian server. The tutorial is incomplete but will be updated whenever more information is discovered.

			'''Note that a lot of the information here is out of date (< Apr 2013). Check [http://wiki.vg/index.php?title=How_to_Write_a_Client&action=history the page history] for what was recently updated.'''

	== Before You Get Started ==		== Before You Get Started ==

imported>Gjum: /* Before You Get Started */ Link to Client_List for existing projects

2015-11-05T18:09:36Z

Before You Get Started: Link to Client_List for existing projects

← Older revision		Revision as of 18:09, 5 November 2015
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	== Before You Get Started ==		== Before You Get Started ==

	* Make sure you don't want to join or fork an existing project instead.		* Make sure you don't want to join or fork an [[Client_List\|existing project]] instead.
	* Ponder how much work it will be.		* Ponder how much work it will be.
	* Download the latest official minecraft server and run it with authentication turned off. Bind it to localhost if you want.		* Download the latest official minecraft server and run it with authentication turned off. Bind it to localhost if you want.

imported>Rom1504: /* How long to wait */ update minecraft-data link

2015-10-17T16:14:56Z

How long to wait: update minecraft-data link

← Older revision		Revision as of 16:14, 17 October 2015
Line 192:		Line 192:
	gold: 0		gold: 0

	for the following fields, see https://github.com/PrismarineJS/minecraft-data/blob/1.8~~/enums~~/blocks.json		for the following fields, see https://github.com/PrismarineJS/minecraft-data/blob/master/data/1.8/blocks.json
	Block.hardness		Block.hardness
	Block.material		Block.material

imported>Gjum: /* Inventory and Crafting */ Add much info

2015-10-14T16:45:02Z

Inventory and Crafting: Add much info

← Older revision		Revision as of 16:45, 14 October 2015
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	== Inventory and Crafting ==		== Inventory and Crafting ==

	When you log in, before you get a 0x0D, you will get a ~~0x68~~ Window Items with ~~your complete~~ inventory including armor. You will then get a series of ~~0x67~~ Set Slot ~~messages~~ repeating the information for ~~each~~ non-empty slot. The slot indexes of these messages are for an inventory window with the crafting zone empty.		When you log in, before you get a 0x0D, you will get a [[Protocol#Window_Items\|Window Items]] with all inventory slots including armor. You will then get a series of [[Protocol#Set_Slot\|Set Slot]] repeating the slot information, one for every non-empty slot in the opened window, plus the cursor slot (which is empty by default, but changes when you click on a slot). The slot indexes of these messages are for an inventory window with the crafting zone empty.

	~~TODO:~~ more info.		By clicking on a block or entity, the client can open a window. After sending the [[Protocol#Player_Block_Placement\|Player Block Placement]] or [[Protocol#Use_Entity\|Use Entity]] packet, the server responds with [[Protocol#Open_Window\|Open Window]], [[Protocol#Window_Items\|Window Items]], several [[Protocol#Set_Slot\|Set Slot]] (one for every non-empty slot in the opened window, plus the cursor slot), and optionally [[Protocol#Window_Property\|Window Property]]. It seems that only the most recently opened window can be interacted with. For more info, look at [[Inventory]].

			Clicking happens by sending [[Protocol#Click_Window\|Click Window]], which the server will answer with a [[Protocol#Confirm_Transaction\|Confirm Transaction]]. If the "Clicked item" is wrong, the click will still be ''executed'' but not ''accepted''.

			If the click was not accepted by the server (accepted = false), the client must answer with [[Protocol#Confirm_Transaction_2\|Confirm Transaction (serverbound)]] to apologize (like with movement), otherwise the server ignores any successive clicks. Additionally, the server answers erroneous clicks with one [[Protocol#Window_Items\|Window Items]] and several [[Protocol#Set_Slot\|Set Slot]] as above, to resynchronize the client with the server.

			The client has to know all clicking behaviour (including crafting recipes) and change the slots accordingly after each click, because the server does not send any [[Protocol#Set_Slot\|Set Slot]], just [[Protocol#Confirm_Transaction\|Confirm Transaction]]. But you can cheat and always send the wrong "Clicked item" in [[Protocol#Click_Window\|Click Window]] to force the server to send you all slots again while still applying your click.

			Crafting is done by placing the correct materials into the crafting grid and clicking on the result slot (always slot nr. 0) to pick up the crafted item. Make sure to correctly update all slots after clicking the result slot, as some recipes (e.g. cake) leave back items in the crafting grid/inventory (e.g. empty buckets).

	== Attacking mobs/players ==		== Attacking mobs/players ==

imported>Phasesaber: Add link to Java implementation of Tool Strengths

2015-10-12T10:15:50Z

Add link to Java implementation of Tool Strengths

← Older revision		Revision as of 10:15, 12 October 2015
Line 95:		Line 95:

	=== How long to wait ===		=== How long to wait ===
			The server requires you to wait for a certain amount of time between sending a StartDiggingPacket and a StopDiggingPacket. Below is some old pseudocode; you can find an updated one [https://gist.github.com/phase/85d3081047cbf3d2f5ae here].

	20 ticks per second		20 ticks per second