第一個應用：如何使用網格渲染器Blend Shapes Unity製作木棍剝皮

1、 Intro

2、Modeling (Blender)

開啟Blender 軟體

調整視角

然後快捷鍵： Shift+A

新增Mesh : Cylinder

頂點數改為：

Rotate Around X Axis : 快捷鍵 R+X+90

Scale ：Y Axis : 快捷鍵Ｓ＋Y

進入Edit Mode : 快捷鍵 Tab

Add more Loops : 快捷鍵 Ctrl + R 然後改變滑鼠的滾輪：就會看到橫向線的變化。

下圖中橫向線都是新增的。

Right click to undo movements

Exit Edit Mode : 快捷鍵 Tab

增加Shape Keys

進入Edit Mode然後，Alt + 橫線選中，然後快捷鍵 S + 0 , 一個關鍵幀就完成了。

重複n次把所有橫線都增加key

然後點選File 匯出 FBX 檔案。

然後匯入Unity工程中。

3、 Setup scene

建立空物件掛點， Wood Holder， Wood ，然後拖拽模型掛上

然後調整模型的旋轉，也可以看到在Blender中新增的 Shape keys 在Unity中有資料，可以在Inspector中改變key的值檢視scene中模型的變化。

替換成更像木頭的材質： wood

場景中需要放另外的物體：刻刀 Knife ，有碰撞體跟剛體(限制運動方向等引數設定)，與控制指令碼Knife.cs

4、Wood Rotation (DoTween)

新增第一個指令碼 Wood.cs 讓木頭先旋轉

using UnityEngine ;
using DG.Tweening ;

public class Wood : MonoBehaviour {
   [SerializeField] private SkinnedMeshRenderer skinnedMeshRenderer ;
   [SerializeField] private Transform woodTransform ;
   [SerializeField] private Vector3 rotationVector ;
   [SerializeField] private float rotationDuration ;

   private void Start () {
      woodTransform
         .DOLocalRotate (rotationVector, rotationDuration, RotateMode.FastBeyond360)
         .SetLoops (-1, LoopType.Restart)
         .SetEase (Ease.Linear) ;
   }

   public void Hit (int keyIndex, float damage) {
      float colliderHeight = 2.39705f ;
      //Skinned mesh renderer key's value is clamped between 0 & 100
      float newWeight = skinnedMeshRenderer.GetBlendShapeWeight (keyIndex) + damage * (100f / colliderHeight) ;
      skinnedMeshRenderer.SetBlendShapeWeight (keyIndex, newWeight) ;
   }
}

執行時就會旋轉了。

5、 Knife Movement

新增指令碼 Knife.cs 移動刀片

using UnityEngine ;

public class Knife : MonoBehaviour {
   [SerializeField] private float movementSpeed ;
   [SerializeField] private float hitDamage ;
   [SerializeField] private Wood wood ;

   [SerializeField] private ParticleSystem woodFx ;

   private ParticleSystem.EmissionModule woodFxEmission ;

   private Rigidbody knifeRb ;
   private Vector3 movementVector ;
   private bool isMoving = false ;

   private void Start () {
      knifeRb = GetComponent<Rigidbody> () ;

      woodFxEmission = woodFx.emission ;
   }

   private void Update () {
      isMoving = Input.GetMouseButton (0) ;

      if (isMoving)
         movementVector = new Vector3 (Input.GetAxis ("Mouse X"), Input.GetAxis ("Mouse Y"), 0f) * movementSpeed * Time.deltaTime ;
   }

   private void FixedUpdate () {
      if (isMoving)
         knifeRb.position += movementVector ;
   }

   private void OnCollisionExit (Collision collision) {
      woodFxEmission.enabled = false ;
   }

   private void OnCollisionStay (Collision collision) {
      Coll coll = collision.collider.GetComponent <Coll> () ;
      if (coll != null) {
         // hit Collider:
         woodFxEmission.enabled = true ;
         woodFx.transform.position = collision.contacts [ 0 ].point ;

         coll.HitCollider (hitDamage) ;
         wood.Hit (coll.index, hitDamage) ;
      }
   }
}

6、Colliders

新增碰撞體：

先調整引數，這樣可以確定每個key的位置

為每個碰撞體新增指令碼 Coll.cs

using UnityEngine ;

public class Coll : MonoBehaviour {
   public int index ;

   BoxCollider boxCollider ;

   private void Awake () {
      boxCollider = GetComponent<BoxCollider> () ;
      index = transform.GetSiblingIndex () ;
   }

   public void HitCollider (float damage) {
      // Resize the collider's height(Y) depends on "damage" 
      if (boxCollider.size.y - damage > 0.0f)
         boxCollider.size = new Vector3 (boxCollider.size.x, boxCollider.size.y - damage, boxCollider.size.z) ;
      else
         Destroy (this) ; // Remove Coll Component from this gameobject
   }
}

7、Wood Deformation (Skinned Mesh Renderer)

Wood.cs 中更改指定key的權重來達到木頭的削皮

   public void Hit (int keyIndex, float damage) {
      float colliderHeight = 2.39705f ;  // 編輯器時碰撞體的size的y值
      //Skinned mesh renderer key's value is clamped between 0 & 100
      float newWeight = skinnedMeshRenderer.GetBlendShapeWeight (keyIndex) + damage * (100f / colliderHeight) ;
      skinnedMeshRenderer.SetBlendShapeWeight (keyIndex, newWeight) ;
   }

Knife.cs 中削刀跟key碰撞體碰撞就改變指定的key的權重

   private void OnCollisionExit (Collision collision) {
      woodFxEmission.enabled = false ;
   }

   private void OnCollisionStay (Collision collision) {
      Coll coll = collision.collider.GetComponent <Coll> () ;
      if (coll != null) {
         // hit Collider:
         woodFxEmission.enabled = true ;
         woodFx.transform.position = collision.contacts [ 0 ].point ;

         coll.HitCollider (hitDamage) ;
         wood.Hit (coll.index, hitDamage) ;
      }
   }