Desynchronization of variables consisting of value from random operation inside of processors.

Redo11 commented 3 months ago

Platforms

Linux

Build

146 steam

Issue

When a processor assigns a random value to a variable, there is an automatic desynchronization between the server and client. I am making a gimmick map, heavily dependent on logic that uses randomized variables in multiple places. It works absolutely fine in single player, but in multiplayer, it causes problems, as effects are spawning in wrong places, resources get added and removed when client synchronizes them back and fake values inside of storage cells being presented client side.

Steps to reproduce

Make a processor, put code that randomizes two values with @mapw and @maph being saved as x and y Next put some code that shows a visual effect at the random positions. Start another instance and join the game. The effect will be spawned in 2 different locations for each client

Mods used

Vanilla

Save file

minedustry 4.msav.zip my map. The boulders spawn effect is played at a wrong place on a separate client and "mined boulders" variable at the top is wrong/fake.

(Crash) logs

No response

Submission

[X] I have updated to the latest release (https://github.com/Anuken/Mindustry/releases) to make sure my issue has not been fixed.
[X] I have searched the closed and open issues to make sure that this problem has not already been reported.
[X] I am not using Foo's Client, and have made sure the bug is not caused by mods I have installed.

camelStyleUser commented 3 months ago

thats like what rand does

camelStyleUser commented 3 months ago

where is the bug

camelStyleUser commented 3 months ago

use sync

Redo11 commented 3 months ago

i am using sync

Redo11 commented 3 months ago

the problem still persists

Redo11 commented 3 months ago

thats like what rand does

I don't think it's intended to cause desynchronization between clients. I have a use case for rand that requires it to be synchronized to be properly playable.

camelStyleUser commented 3 months ago

the problem still persists

how often are you using sync and are you waiting at least a little bit

Redo11 commented 3 months ago

the problem still persists

how often are you using sync and are you waiting at least a little bit

i am using the function constantly. The whole gameplay of my map depends on it.

camelStyleUser commented 3 months ago

the problem still persists

how often are you using sync and are you waiting at least a little bit

i am using the function constantly. The whole gameplay of my map depends on it.

it has a delay

camelStyleUser commented 3 months ago

certainly you can wait 3 ticks

Redo11 commented 3 months ago

What do you mean wait a tick? Where? When? And why is that required and not specified?

camelStyleUser commented 3 months ago

What do you mean wait a tick? Where? When? And why is that required and not specified?

its 3 ticks my bad

Redo11 commented 3 months ago

Since it's per variable, it should be fine. I already have 0.03 wait, I will bump it to 0.05, but it shouldn't be the main cause either.

Redo11 commented 3 months ago

Spawning visual effects appear on the client side, where on the host/server side they do not exist, since nothing is spawning. The client thinks the X and Y variables as well as random wait time are absolutely different variables from the truth of host.

Redo11 commented 3 months ago

↑Client ↑ host

camelStyleUser commented 3 months ago

Spawning visual effects appear on the client side, where on the host/server side they do not exist, since nothing is spawning. The client thinks the X and Y variables as well as random wait time are absolutely different variables from the truth of host.

do you expect every single double to be synced over the network?

Anuken commented 3 months ago

Attempts are made to synchronize the random seed, but it's not reliable, and never will be. Don't use random when synchronization matters.

Anuken / Mindustry