Add cross-platform determinism (#2)

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "rust-analyzer.linkedProjects": ["./addons/godot-rapier-3d/rust/Cargo.toml"]
+}

CONTRIBUTING.md

@@ -13,6 +13,7 @@
 
 - Follow [semver](https://semver.org/) when releasing new versions
 - If functionality doesn't need to directly interact with Rapier and doesn't need to be optimized, prefer writing it in GDScript
+- Any mutations to the Rapier pipeline need to be fed through the action queue in order to ensure determinism
 
 ## Development quickstart
 
@@ -25,22 +26,6 @@
 
 Please raise an issue and provide reproducible steps or a minimal reproduction project, which is a small Godot project which reproduces the issue, with no unnecessary files included.
 
-## Known issues
-
-- Using any of the logging macros (`crate::error!` etc.) grabs a mutable reference to the engine singleton. If you already have done this in the same function, Godot will crash. You instead need to pass the engine bind:
-
-  ```rust
-  fn my_func() {
-    let mut engine = crate::get_engine!();
-    let mut bind = engine.bind_mut();
-    // ...stuff...
-    // crate::error!("This will crash Godot"); // INCORRECT
-    crate::error!(bind; "This is fine");
-  }
-  ```
-
-  the `get_engine!` macro should be upgraded to prevent such double access cases
-
 ## Roadmap
 
 - [x] Visualize colliders

README.md

@@ -12,7 +12,7 @@ It is _not_ a drop-in replacement for the Godot physics engine. Rapier nodes ope
 
 ### Features
 
-- Cross platform determinism (TBC - needs testing)
+- Cross platform determinism (confirmed via [actions](https://github.com/deltasiege/godot-rapier-3d/actions/workflows/build-and-test.yml)!)
 - Physics state manual stepping
 - Physics state saving & loading
 
@@ -54,22 +54,13 @@ Obtain a [hash](https://docs.godotengine.org/en/stable/classes/class_array.html#
 var initial_snapshot
 
 func _ready():
-	Rapier3D.physics_ready.connect(_on_physics_ready)
-
-func _on_physics_ready():
   initial_snapshot = Rapier3D.get_state()
   var hash = Rapier3D.get_hash(initial_snapshot)
 
 func _on_foo():
   Rapier3D.set_state(initial_snapshot)
 ```
 
-### Why `_on_physics_ready`?
-
-Colliders need 1 extra frame to attach to physics bodies. Therefore it's recommended that you don't use `Rapier3D.get_state()` within a `_ready()` function because colliders will not be attached yet.
-
-Instead, you should connect to the `Rapier3D.physics_ready` signal as shown above.
-
 ## Why does this exist?
 
 Currently Godot does not support [on-demand physics simulation](https://github.com/godotengine/godot-proposals/issues/2821), does not have [built-in snapshotting](https://github.com/godotengine/godot-proposals/issues/7041), and is also not [deterministic](https://gafferongames.com/post/deterministic_lockstep).
@@ -82,10 +73,6 @@ Luckily, Godot 4 provides a great [extension system][gdext-link] and [Rapier][ra
 
 - No mobile support ([godot-rust](https://github.com/godot-rust/gdext/issues/24))
 
-## Known issues
-
-- `Project -> Reload current project` can cause the engine to not load properly - errors will print to the godot console. These errors can be safely ignored. To eliminate them, close godot entirely and reopen your project from the project manager.
-
 ## Contributing
 
 See [CONTRIBUTING.md](CONTRIBUTING.md)

addons/godot-rapier-3d/Rapier3D.gd

@@ -1,13 +1,14 @@
+@tool
 extends Node3D
 
 const utils = preload("res://addons/godot-rapier-3d/gdscript/utils.gd")
 const physics_state = preload("res://addons/godot-rapier-3d/gdscript/physics_state.gd")
 
-signal physics_ready
+func _ready():
+	Rapier3DEngine._process()
 
 func _physics_process(_delta):
-	if Engine.get_physics_frames() != 1: return # Need to wait a few frames for colliders to properly mount in the tree
-	physics_ready.emit()
+	Rapier3DEngine._process()
 
 func step() -> void:
 	Rapier3DEngine.step()

addons/godot-rapier-3d/Rapier3DDebugger.gd

@@ -69,4 +69,9 @@ func _draw_line(a, b, color):
 
 func _should_run():
 	if Engine.is_editor_hint(): return run_in_editor
-	else: return run_in_game
+	else: 
+		var current_scene = get_tree().current_scene
+		var scene_path = current_scene.scene_file_path
+		var is_test_scene = scene_path.contains("res://tests/")
+		if is_test_scene: return false
+		return run_in_game

addons/godot-rapier-3d/debug_info.gd

@@ -0,0 +1,5 @@
+@tool
+extends EditorScript
+
+func _run():
+	Rapier3DEngine.print_debug_info()

addons/godot-rapier-3d/gdscript/physics_controls.gd

@@ -15,14 +15,11 @@ var godot_hash
 func _ready():
 	_update_should_show()
 	if !should_show: return
-	Rapier3D.physics_ready.connect(_on_physics_ready)
+	initial_snapshot = _save()
 	if !Engine.is_editor_hint(): 
 		play_button.set_pressed(true)
 		play = true
 
-func _on_physics_ready():
-	initial_snapshot = _save()
-
 func _physics_process(_delta):
 	if !should_show: return
 	if play: Rapier3D.step()

addons/godot-rapier-3d/gdscript/physics_state.gd

@@ -1,6 +1,6 @@
 const utils = preload("res://addons/godot-rapier-3d/gdscript/utils.gd")
 
-static func _get_physics_state(root: Node3D):
+static func _get_physics_state(root: Node):
 	var state = PackedByteArray()
 	var physics_objects = _get_all_physics_objects(root)
 	var sorted = _sort_by_iid(physics_objects)

addons/godot-rapier-3d/gdscript/project_settings.gd

@@ -3,15 +3,15 @@ extends Object
 var _property_order: int = 1000
 
 var _project_settings = [
-	{ "name": "debug/rapier_3d/logging_level", "type": TYPE_INT, "default": 2, "hint": PROPERTY_HINT_ENUM, "hint_string": "Error,Warning,Info,Debug" },
+	{ "name": "debug/rapier_3d/logging_level", "type": TYPE_STRING, "default": "Info", "hint": PROPERTY_HINT_ENUM, "hint_string": "Off,Error,Warning,Info,Debug,Trace" },
 	{ "name": "debug/rapier_3d/debug_in_game", "type": TYPE_BOOL, "default": true },
 	{ "name": "debug/rapier_3d/debug_in_editor", "type": TYPE_BOOL, "default": true },
 	{ "name": "debug/rapier_3d/show_colliders", "type": TYPE_BOOL, "default": true },
 	{ "name": "debug/rapier_3d/show_ui", "type": TYPE_BOOL, "default": true },
 	{ "name": "physics/rapier_3d/gravity_vector", "type": TYPE_VECTOR3, "default": Vector3(0, -9.8, 0) },
 ]
 
-func _add_project_setting(name: String, type: int, default, hint = null, hint_string = null) -> void:
+func _add_project_setting(name: String, type: int, default, hint = null, hint_string = null, restart_if_changed = false) -> void:
 	if not ProjectSettings.has_setting(name): ProjectSettings.set_setting(name, default)
 	ProjectSettings.set_initial_value(name, default)
 	ProjectSettings.set_order(name, _property_order)
@@ -20,13 +20,14 @@ func _add_project_setting(name: String, type: int, default, hint = null, hint_st
 	if hint != null: info['hint'] = hint
 	if hint_string != null: info['hint_string'] = hint_string
 	ProjectSettings.add_property_info(info)
+	ProjectSettings.set_restart_if_changed(name, restart_if_changed)
 
 func _remove_project_setting(name: String) -> void:
 	if ProjectSettings.has_setting(name): ProjectSettings.set_setting(name, null)
 
 func add_project_settings() -> void:
 	for setting in _project_settings:
-		_add_project_setting(setting.name, setting.type, setting.default, setting.get("hint", null), setting.get("hint_string", null))
+		_add_project_setting(setting.name, setting.type, setting.default, setting.get("hint", null), setting.get("hint_string", null), setting.get("restart_if_changed", false))
 
 func remove_project_settings() -> void:
 	for setting in _project_settings: