Feature: Add support for inverted mouse camera horizontal setting to player start

src/document/migrate-scene-document.ts

@@ -29,6 +29,7 @@ import {
   createCameraRigPlayerTargetRef,
   createCameraRigWorldPointTargetRef,
   DEFAULT_PLAYER_START_ALLOW_LOOK_INPUT_TARGET_SWITCH,
+  DEFAULT_PLAYER_START_INVERT_MOUSE_CAMERA_HORIZONTAL,
   DEFAULT_PLAYER_START_INTERACTION_ANGLE_DEGREES,
   DEFAULT_PLAYER_START_GAMEPAD_BINDINGS,
   DEFAULT_PLAYER_START_INTERACTION_REACH_METERS,
@@ -3348,6 +3349,11 @@ function readPlayerStartEntity(value: unknown, label: string): EntityInstance {
       `${label}.targetButtonCyclesActiveTarget`,
       DEFAULT_PLAYER_START_TARGET_BUTTON_CYCLES_ACTIVE_TARGET
     ),
+    invertMouseCameraHorizontal: readOptionalBoolean(
+      value.invertMouseCameraHorizontal,
+      `${label}.invertMouseCameraHorizontal`,
+      DEFAULT_PLAYER_START_INVERT_MOUSE_CAMERA_HORIZONTAL
+    ),
     movementTemplate: readPlayerStartMovementTemplate(
       value.movementTemplate,
       `${label}.movementTemplate`
@@ -5500,6 +5506,7 @@ export function migrateSceneDocument(source: unknown): SceneDocument {
     source.version !== PLAYER_START_INTERACTION_REACH_SCENE_DOCUMENT_VERSION &&
     source.version !== PLAYER_START_INTERACTION_ANGLE_SCENE_DOCUMENT_VERSION &&
     source.version !== PLAYER_START_TARGETING_SETTINGS_SCENE_DOCUMENT_VERSION &&
+    source.version !== PLAYER_START_MOUSE_INVERT_SCENE_DOCUMENT_VERSION &&
     source.version !== PLAYER_START_INTERACT_BINDINGS_SCENE_DOCUMENT_VERSION &&
     source.version !== PLAYER_START_MOVEMENT_TEMPLATE_SCENE_DOCUMENT_VERSION &&
     source.version !== PROJECT_NAME_SCENE_DOCUMENT_VERSION &&

src/document/scene-document-validation.ts

@@ -2699,6 +2699,17 @@ function validatePlayerStartEntity(
     );
   }
 
+  if (typeof entity.invertMouseCameraHorizontal !== "boolean") {
+    diagnostics.push(
+      createDiagnostic(
+        "error",
+        "invalid-player-start-invert-mouse-camera-horizontal",
+        "Player Start invertMouseCameraHorizontal must remain a boolean.",
+        `${path}.invertMouseCameraHorizontal`
+      )
+    );
+  }
+
   if (!isPlayerStartMovementTemplateKind(entity.movementTemplate?.kind)) {
     diagnostics.push(
       createDiagnostic(

src/document/scene-document.ts

@@ -29,7 +29,8 @@ import {
 } from "../sequencer/project-sequences";
 import type { Terrain } from "./terrains";
 
-export const SCENE_DOCUMENT_VERSION = 83 as const;
+export const SCENE_DOCUMENT_VERSION = 84 as const;
+export const PLAYER_START_MOUSE_INVERT_SCENE_DOCUMENT_VERSION = 84 as const;
 export const PLAYER_START_TARGETING_SETTINGS_SCENE_DOCUMENT_VERSION =
   83 as const;
 export const PLAYER_START_INTERACT_BINDINGS_SCENE_DOCUMENT_VERSION =

src/runtime-three/runtime-scene-build.ts

@@ -282,6 +282,7 @@ export interface RuntimePlayerStart {
   interactionAngleDegrees: number;
   allowLookInputTargetSwitch: boolean;
   targetButtonCyclesActiveTarget: boolean;
+  invertMouseCameraHorizontal: boolean;
   movement: RuntimePlayerMovement;
   inputBindings: PlayerStartInputBindings;
   collider: FirstPersonPlayerShape;
@@ -1599,6 +1600,7 @@ function buildRuntimeSceneCollections(
           interactionAngleDegrees: entity.interactionAngleDegrees,
           allowLookInputTargetSwitch: entity.allowLookInputTargetSwitch,
           targetButtonCyclesActiveTarget: entity.targetButtonCyclesActiveTarget,
+          invertMouseCameraHorizontal: entity.invertMouseCameraHorizontal,
           movement: buildRuntimePlayerMovement(entity.movementTemplate),
           inputBindings: clonePlayerStartInputBindings(entity.inputBindings),
           collider: buildRuntimePlayerShape(entity)
@@ -2001,6 +2003,8 @@ export function buildRuntimeSceneFromDocument(
             playerStartEntity.allowLookInputTargetSwitch,
           targetButtonCyclesActiveTarget:
             playerStartEntity.targetButtonCyclesActiveTarget,
+          invertMouseCameraHorizontal:
+            playerStartEntity.invertMouseCameraHorizontal,
           movement: cloneRuntimePlayerMovement(playerMovement),
           inputBindings: clonePlayerStartInputBindings(playerInputBindings),
           collider: playerCollider