オートアイムーブメントの目ボーンの最大移動角度が、VRMLookAtBoneApplyerで指定された角度のうち最小値になるようにした

Editor/VRChatsBugsWorkaround.cs

@@ -30,6 +30,16 @@ public class VRChatsBugsWorkaround
             "vrc.lowerlid_right"
         };
 
+        /// <summary>
+        /// オートアイムーブメントにおける目のボーンの回転角度の最大値。
+        /// </summary>
+        /// <remarks>
+        /// 参照:
+        /// Eye trackingの実装【VRChat技術情報】 — VRChatパブリックログ
+        /// <https://jellyfish-qrage.hatenablog.com/entry/2018/07/25/034610>
+        /// </remarks>
+        internal static readonly int MaxAutoEyeMovementDegree = 30;
+
         /// <summary>
         /// クラスに含まれる処理を適用します。
         /// </summary>
@@ -44,6 +54,7 @@ internal static void Apply(GameObject avatar, string assetsPath, bool enableAuto
             if (enableAutoEyeMovement)
             {
                 VRChatsBugsWorkaround.EnableAutoEyeMovement(avatar: avatar, assetsPath: assetsPath);
+                VRChatsBugsWorkaround.ApplyAutoEyeMovementDegreeMapping(avatar: avatar, assetsPath: assetsPath);
             }
             else {
                 VRChatsBugsWorkaround.DisableAutoEyeMovement(avatar: avatar, assetsPath: assetsPath);
@@ -274,6 +285,92 @@ private static void DisableAutoEyeMovement(GameObject avatar, string assetsPath)
             ApplyAvatarDescription(avatar: avatar, assetsPath: assetsPath, avatarDescription: avatarDescription);
         }
 
+        /// <summary>
+        /// オートアイムーブメントの目ボーンの角度を、<see cref="VRMLookAtBoneApplyer"/>で指定された角度のうち最小値になるようにウェイトペイントを行います。
+        /// </summary>
+        /// <param name="avatar"></param>
+        /// <remarks>
+        /// 参照:
+        /// Eye trackingの実装【VRChat技術情報】 — VRChatパブリックログ
+        /// <https://jellyfish-qrage.hatenablog.com/entry/2018/07/25/034610>
+        /// 海行プログラムさんのツイート: “自前でスキンメッシュをどうこうするにあたって役に立ったUnityマニュアルのコード。bindposeってのを各ボーンに設定しないといけないんだけど、ボーンのtransform.worldToLocalMatrixを入れればＯＫ　　https://t.co/I2qKb6uQ8a”
+        /// <https://twitter.com/kaigyoPG/status/807648864081616896>
+        /// </remarks>
+        private static void ApplyAutoEyeMovementDegreeMapping(GameObject avatar, string assetsPath)
+        {
+            var lookAtBoneApplyer = avatar.GetComponent<VRMLookAtBoneApplyer>();
+            if (!lookAtBoneApplyer)
+            {
+                return;
+            }
+
+            float minDegree = new[] { lookAtBoneApplyer.HorizontalOuter, lookAtBoneApplyer.HorizontalInner, lookAtBoneApplyer.VerticalDown, lookAtBoneApplyer.VerticalUp }
+                .Select(mapper => mapper.CurveYRangeDegree)
+                .Min();
+            float eyeBoneWeight = minDegree / VRChatsBugsWorkaround.MaxAutoEyeMovementDegree;
+            float headBoneWeight = 1 - eyeBoneWeight;
+
+            Transform headBone = avatar.GetComponent<VRMFirstPerson>().FirstPersonBone;
+            var eyeBones = new[] { HumanBodyBones.RightEye, HumanBodyBones.LeftEye }
+                .Select(id => avatar.GetComponent<Animator>().GetBoneTransform(humanBoneId: id));
+
+            foreach (var renderer in avatar.GetComponentsInChildren<SkinnedMeshRenderer>())
+            {
+                Transform[] bones = renderer.bones;
+                IEnumerable<int> eyeBoneIndexes = eyeBones.Select(eyeBone => bones.IndexOf(target: eyeBone)).Where(index => index >= 0);
+                if (eyeBoneIndexes.Count() == 0)
+                {
+                    continue;
+                }
+
+                var mesh = VRChatsBugsWorkaround.DuplicateObject(avatar: avatar, assetsPath: assetsPath, obj: renderer.sharedMesh) as Mesh;
+
+                int headBoneIndex = bones.IndexOf(target: headBone);
+                if (headBoneIndex < 0)
+                {
+                    renderer.bones = bones.Concat(new[] { headBone }).ToArray();
+                    headBoneIndex = bones.Length;
+                    mesh.bindposes = mesh.bindposes.Concat(new[] { headBone.worldToLocalMatrix }).ToArray();
+                }
+
+                mesh.boneWeights = mesh.boneWeights.Select(boneWeight => {
+                    IEnumerable<float> weights = new[] { boneWeight.weight0, boneWeight.weight1, boneWeight.weight2, boneWeight.weight3 }.Where(weight => weight > 0);
+                    IEnumerable<int> boneIndexes = new[] { boneWeight.boneIndex0, boneWeight.boneIndex1, boneWeight.boneIndex2, boneWeight.boneIndex3 }.Take(weights.Count());
+                    if (eyeBoneIndexes.Intersect(boneIndexes).Count() == 0 || boneIndexes.Contains(headBoneIndex))
+                    {
+                        return boneWeight;
+                    }
+
+                    foreach (int eyeBoneIndex in eyeBoneIndexes)
+                    {
+                        int index = boneIndexes.ToList().FindIndex(boneIndex => boneIndex == eyeBoneIndex);
+                        switch (index)
+                        {
+                            case 0:
+                                boneWeight.weight0 = eyeBoneWeight;
+                                boneWeight.boneIndex1 = headBoneIndex;
+                                boneWeight.weight1 = headBoneWeight;
+                                break;
+                            case 1:
+                                boneWeight.weight1 = eyeBoneWeight;
+                                boneWeight.boneIndex2 = headBoneIndex;
+                                boneWeight.weight2 = headBoneWeight;
+                                break;
+                            case 2:
+                                boneWeight.weight2 = eyeBoneWeight;
+                                boneWeight.boneIndex3 = headBoneIndex;
+                                boneWeight.weight3 = headBoneWeight;
+                                break;
+                        }
+                    }
+
+                                return boneWeight;
+                }).ToArray();
+
+                renderer.sharedMesh = mesh;
+            }
+        }
+
         /// <summary>
         /// ダミー用の空のメッシュを生成します。
         /// </summary>