Untitled VR Game

Goal: Make a VR game in godot where you can throw a physics ball between two players.

Current Setup

Godot has autoloads which are singleton nodes that are configured to load on startup. Current we use three:

• SyncManager: The main coordinator for rollback networking. It is defined in ./gdrollback/src/sync_manager.rs. More details on it's usage can be found here: https://github.com/Kethku/gdrollback

  The important pieces for the current project are that it will call network_process and load_state on any nodes that are in the networked group. It also has a spawn function on it which spawns scenes in a way that works with the rollback system.

• InputManager: The node which the sync_manager uses to retrieve input from the local player. It is defined in ./autoloads/InputManagerAL.gd.

• World: The node that contains the physics world. It is defined in ./gdrapier3d/src/world.rs.

Startup Flow

main.gd is attached to the root of the default scene and is responsible for setting up the SyncManager and starting the game loop. On startup, _ready is called which hooks up event callbacks from the SyncManager, parses command line arguments to decide whether to start as a host or client, and sets up the player scene either as a puppet or xr origin.

After connected to the remote player, the _on_sync_manager_started callback is called which moves the player to one of the positions defined nodes in the SpawnPoints group, and spawns remote player puppets for the other connected peers.

main.tscn

The main scene contains R3DRigidBody nodes for the floor, and stack of boxes, environment information to facilitate rendering, and a series of Node3D spawn point nodes to define where players should spawn.

The R3DRigidBody nodes automatically get added to the World autoload when they are added to the tree (in this case on startup). There are R3DCuboidColliders and MeshInstance3D nodes as children for each of the boxes which also get automatically registered to their parent in the physics system. No code is necessary to network these objects beyond their base types.

Player.gd

The majority of the actual logic in the current setup is defined in Player.gd which is responsible for updating the player hand and head mesh positions, and processing local input to spawn balls and update their positions while grabbed by the player.

Since the spawned ball objects are R3DRigidBody nodes, we can use the functions on them like add_force, apply_impulse etc to move them around.