void CastSkill()
{
skillSprite = Resources.Load <Sprite>("skillSprite");
GameObject gameObject = new GameObject();
var spriteRenderer = gameObject.AddComponent <SpriteRenderer>();
var r1 = gameObject.AddComponent <CircleCollider2D>().radius;
var r2 = GetComponent <CircleCollider2D>().radius;
spriteRenderer.sprite = skillSprite;
skillEffect = Sprite.Instantiate(skillSprite, rb.position, Quaternion.identity);//在这里创建Sprite
gameObject.transform.localScale = new Vector3(0.2f, 0.2f, 0.2f);
Vector3 mousePosInWorld = Camera.main.ScreenToWorldPoint(Input.mousePosition);
var rbpos3d = new Vector3(rb.position.x, rb.position.y, 0);
var pos = mousePosInWorld - rbpos3d;
pos.z = 0;
gameObject.transform.position = rbpos3d + pos.normalized * (r1 + r2);
var skillRigid = gameObject.AddComponent <Rigidbody2D>();
skillRigid.mass = 0;
skillRigid.velocity = pos.normalized * skillSpeed;
skillRigid.gravityScale = 0;
var skillController = gameObject.AddComponent <SkillController>();
skillController.duration = 0.3f;
//audio
musicController.useskill();
}