Unity中Skinned Mesh Renderer Blend Shapes小试

Posted 2021-05-24 u010019717

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第一个应用：如何使用网格渲染器Blend Shapes Unity制作木棍剥皮

1、 Intro

2、Modeling (Blender)

打开Blender 软件

调整视角

然后快捷键： Shift+A

添加Mesh : Cylinder

顶点数改为：

Rotate Around X Axis : 快捷键 R+X+90

Scale ：Y Axis : 快捷键Ｓ＋Y

进入Edit Mode : 快捷键 Tab

Add more Loops : 快捷键 Ctrl + R 然后改变鼠标的滚轮：就会看到横向线的变化。

下图中横向线都是新增的。

Right click to undo movements

Exit Edit Mode : 快捷键 Tab

增加Shape Keys

进入Edit Mode然后，Alt + 横线选中，然后快捷键 S + 0 , 一个关键帧就完成了。

重复n次把所有横线都增加key

然后点击File 导出 FBX 文件。

然后导入Unity工程中。

3、 Setup scene

创建空对象挂点， Wood Holder， Wood ，然后拖拽模型挂上

然后调整模型的旋转，也可以看到在Blender中添加的 Shape keys 在Unity中有数据，可以在Inspector中改变key的值查看scene中模型的变化。

替换成更像木头的材质： wood

场景中需要放另外的物体：刻刀 Knife ，有碰撞体跟刚体(限制运动方向等参数设置)，与控制脚本Knife.cs

4、Wood Rotation (DoTween)

添加第一个脚本 Wood.cs 让木头先旋转

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) ;
   }
}

运行时就会旋转了。

5、 Knife Movement

添加脚本 Knife.cs 移动刀片

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

添加碰撞体：

先调整参数，这样可以确定每个key的位置

为每个碰撞体添加脚本 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的权重来达到木头的削皮

   public void Hit (int keyIndex, float damage) {
      float colliderHeight = 2.39705f ;  // 编辑器时碰撞体的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碰撞体碰撞就改变指定的key的权重

   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) ;
      }
   }