Unity3D Notes

[dabing1022]

1.Look towards player

using UnityEngine;
using System.Collections;

public class LookTowardMouse : MonoBehaviour {

     void Update () 
     {
         //Mouse Position in the world. It's important to give it some distance from the camera. 
         //If the screen point is calculated right from the exact position of the camera, then it will
         //just return the exact same position as the camera, which is no good.
         Vector3 mouseWorldPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition + Vector3.forward * 10f);

         //Angle between mouse and this object
         float angle = AngleBetweenPoints(transform.position, mouseWorldPosition);

         //Ta daa
         transform.rotation =  Quaternion.Euler (new Vector3(0f,0f,angle));
     }

     float AngleBetweenPoints(Vector2 a, Vector2 b) {
         return Mathf.Atan2(a.y - b.y, a.x - b.x) * Mathf.Rad2Deg;
     }  
 }

[dabing1022]

• 当RigidBody2D的质量属性被设置为0时，刚体的质量变为无限大，此时刚体相当于静态刚体，永远一动不动。但是在Unity中你是无法把一个RigidBody2D的质量设置为0的，所以，当你想创建一个静态刚体时，只需要创建碰撞器，而不需要创建RigidBody2D。
• 当我们勾选了is Kenamatic选项时，这个RigidBody2D就不再受物理引擎控制，我们这时候需要通过Transform来控制RigidBody2D的移动，这个选项经常在脚本里对其进行设置。
• 当Gravity Scale设置为0时，该刚体不再受重力影响。