Deterministic physics extension based on rapier3d for godot 4

Make sure you have rust installed via https://rustup.rs/

Once installed, build the project with cargo build; cargo build --release

Create a .gdextension file that contains something like the following:

[configuration]
entry_symbol = "gdext_rust_init"
compatibility_minimum = 4.1
reloadable = true

[libraries]
windows.debug.x86_64 = "res://{PATH TO THIS REPO}/target/debug/gdrapier3d.dll"
windows.release.x86_64 = "res://{PATH TO THIS REPO}/target/release/gdrapier3d.dll"

This extension is a relatively thin wrapper over the https://rapier.rs/ physics engine and as such provides deterministic physics. In its current version, the system is designed to be ran via gdrollback a sibling extension for rollback networking in godot 4.0, but it wouldn't take much to enable it's use in other contexts.

To work properly a R3DWorld node is registered as an autoload. This node is responsible for managing bodies and colliders in the scene.

R3DRigidBody nodes are automatically registered with the R3DWorld node and will have their transform updated and overwritten. R3D{Shape}Collider nodes added as children to a R3DRigidBody serve as the collision shape.