Correction step to add root bone if missing from skeleton (#25)

tools/gltf-avatar-exporter/src/scene/correction-steps/connectRoot.ts

@@ -0,0 +1,53 @@
+import * as THREE from "three";
+import { Group } from "three";
+
+import { LogMessage, Step } from "./types";
+
+export const connectRootCorrectionStep: Step = {
+  name: "connectRoot",
+  action: (group: Group) => {
+    const rootBone = group.getObjectByName("root") as THREE.Bone;
+    if (!rootBone) {
+      return {
+        didApply: false,
+        topLevelMessage: {
+          level: "error",
+          message: "Could not find root bone. Cannot connect root.",
+        },
+      };
+    }
+    const logs: Array<LogMessage> = [];
+    group.traverse((child) => {
+      const asSkinnedMesh = child as THREE.SkinnedMesh;
+      if (asSkinnedMesh.isSkinnedMesh) {
+        const skeleton = asSkinnedMesh.skeleton;
+        if (skeleton.bones.indexOf(rootBone) === -1) {
+          skeleton.bones.push(rootBone);
+          logs.push({
+            level: "info",
+            message: `Added root bone to ${asSkinnedMesh.name}.`,
+          });
+        }
+      }
+    });
+
+    if (logs.length === 0) {
+      return {
+        didApply: false,
+        topLevelMessage: {
+          level: "info",
+          message: "No skinned meshes with missing roots to fix.",
+        },
+        logs,
+      };
+    }
+    return {
+      didApply: true,
+      topLevelMessage: {
+        level: "info",
+        message: "Applied root to skinned meshes.",
+      },
+      logs,
+    };
+  },
+};

tools/gltf-avatar-exporter/src/scene/correction-steps/runFixes.ts

@@ -1,4 +1,5 @@
 import { boneDedupingCorrectionStep } from "./boneDeduping";
+import { connectRootCorrectionStep } from "./connectRoot";
 import { fixBonesScaleCorrectionStep } from "./fixBonesScale";
 import { fixMeshScaleCorrectionStep } from "./fixMeshScale";
 import { levelOfDetailDedupingCorrectionStep } from "./lodDeduping";
@@ -20,6 +21,7 @@ export const correctionSteps = [
   fixMeshScaleCorrectionStep,
   fixBonesScaleCorrectionStep,
   boneDedupingCorrectionStep,
+  connectRootCorrectionStep,
   rotateRootCorrectionStep,
   rotatePelvisCorrectionStep,
   removeVertexColorsCorrectionStep,