2D Liquid Simulator (In Godot Engine)

Originally created by Tterrasson (repository) and recreated by me, this plugin offers a set of three 2D nodes to simulate the behavior of liquids.

Warning

Although I have a version of this plugin for Godot 4.2, the next updates I release will often be for the newer version of Godot (4.3+), as it is tiring to change the code twice or more.

Tutorial

I recorded this video showing the simulator in operation and teaching how to use it. But I apologize, because in it I am limited to my mother tongue, Portuguese.

Documentation

The entire code API is documented and can be viewed in the Godot docs tab. If you have any difficulty with this, I recommend this video.

Who its work?

The LiquidServer stores the position of each instance of a Liquid and manages the flow of the quantity of each Liquid when necessary or requested by the API. When the flow stops permanently, LiquidServer stops running to increase performance.

It also decides when to update the Liquid sprite and checks when a cell is available or not.

Is it possible to detect collisions with a Liquid?

Yes, it is possible, but it comes at a performance cost, of course. Each Liquid cell is actually an instance of a packaged scene, so it can contain an Area2D, for example. But it is not recommended to transform a Liquid into some type of PhysicBody (this costs a lot of performance).

But a tip for this situation: if you are going to use Area2D, mark monitorable with false, leave it as a child of the Liquid sprite and make it a little smaller than it.

Performance Guide

• Small quadrants on LiquidServer equals more Liquid instances to render and process (i.e. less performance);
• Higher values ​​of epsilon in LiquidServer will make the server stop faster, but will harm the horizontal distribution of Liquid;
• Do not keep calling LiquidServer's start method too frequently, this may harm the server's automatic stop;
• Combining shader + canvas group can give beautiful results, but it costs a lot of performance (The third example I left uses this);
• Liquids that are in a long-lasting fall are automatically deleted by LiquidServer, and this can be configured in the max_falls variable. But even so, it is not recommended to place blocks outside the map.

Monitors

So that you can evaluate the performance of the simulation, some data is added to the Godot monitors tab.