From e7f313a1d6cf0bd737c7d6ff9c305b87e2ce0808 Mon Sep 17 00:00:00 2001
From: Giga <gigabyte5671@gmail.com>
Date: Mon, 4 Sep 2023 14:16:59 +1200
Subject: [PATCH] Update the local avatar's nametag position with the hip bone
 position

Allows the nametag to move up/down along with animations.

Related to #142.
---
 src/modules/entity/entities/NametagEntity.ts | 20 +++++++++++++++++---
 src/modules/scene/vscene.ts                  |  5 +++--
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/modules/entity/entities/NametagEntity.ts b/src/modules/entity/entities/NametagEntity.ts
index 813e65b0..f42d94e0 100644
--- a/src/modules/entity/entities/NametagEntity.ts
+++ b/src/modules/entity/entities/NametagEntity.ts
@@ -12,7 +12,7 @@
 /* eslint-disable @typescript-eslint/no-magic-numbers */
 /* eslint-disable new-cap */
 
-import { AbstractMesh,
+import { type AbstractMesh,
     Color3,
     DynamicTexture,
     Matrix,
@@ -25,6 +25,7 @@ import { AbstractMesh,
 import { DEFAULT_MESH_RENDER_GROUP_ID } from "@Modules/object";
 import { Renderer } from "@Modules/scene";
 import { userStore } from "@Stores/index";
+import { Hysteresis } from "@Modules/utility/hysteresis";
 
 /**
  * Contains all of the memoized nametag meshes within the scene.
@@ -119,7 +120,7 @@ export class NametagEntity {
      */
     public static create(
         object: Mesh | AbstractMesh | TransformNode,
-        height: number,
+        height: number | (() => number),
         name: string,
         icon = false,
         color?: Color3,
@@ -310,7 +311,15 @@ export class NametagEntity {
 
         // Position the nametag above the center of the object.
         const positionOffset = new Vector3(0, 0.15, 0);
-        mesh.position = new Vector3(positionOffset.x, height + positionOffset.y, positionOffset.z);
+        let h = 0;
+        let heightHysteresis: Nullable<Hysteresis> = null;
+        if (typeof height === "number") {
+            h = height + positionOffset.y;
+        } else {
+            h = height() + positionOffset.y;
+            heightHysteresis = new Hysteresis(() => height() + positionOffset.y, 100, positionOffset.y);
+        }
+        mesh.position = new Vector3(positionOffset.x, h, positionOffset.z);
 
         const scaleAdjustmentFactorX = object.scaling.x > 0 ? 1 / object.scaling.x : 1;
         const scaleAdjustmentFactorY = object.scaling.y > 0 ? 1 / object.scaling.y : 1;
@@ -331,6 +340,11 @@ export class NametagEntity {
             if (!mesh) {
                 return;
             }
+            // Update the nametag's position.
+            if (heightHysteresis) {
+                mesh.position.y = heightHysteresis.get();
+            }
+            // Update the nametag's opacity.
             const avatar = Renderer.getScene()?.getMyAvatar();
             if (avatar) {
                 const avatarPosition = avatar.getAbsolutePosition().clone();
diff --git a/src/modules/scene/vscene.ts b/src/modules/scene/vscene.ts
index dfdbe721..914ce850 100644
--- a/src/modules/scene/vscene.ts
+++ b/src/modules/scene/vscene.ts
@@ -323,7 +323,8 @@ export class VScene {
             }
             const avatarHeight = boundingVectors.max.y - boundingVectors.min.y;
 
-            const hipPosition = result.skeleton?.bones.find((bone) => bone.name === "Hips")?.position;
+            const hipBone = result.skeleton?.bones.find((bone) => bone.name === "Hips");
+            const hipPosition = hipBone?.position;
 
             // Reload the avatar animations file in case the new avatar is a different size than the previous one.
             // The browser cache will prevent this from being fetched over the network if the avatar is switched frequently.
@@ -380,7 +381,7 @@ export class VScene {
             let nametagColor = userStore.account.isAdmin ? Color3.FromHexString(applicationStore.theme.colors.primary) : undefined;
             NametagEntity.create(
                 this._myAvatar,
-                avatarHeight,
+                () => (hipBone?.position.y ?? avatarHeight / 2) + avatarHeight / 2,
                 userStore.avatar.displayName,
                 false,
                 nametagColor