【游戏-unity】Unity实现水面漂浮效果。以unity的StandardAssets中的water资源为基础，介绍物体在水中的漂浮效果实现。

Floatage.cs

//1.给水体添加碰撞体
//需要注意的是要勾选Is Trigger，y方向的范围要控制好，不然可能会出现物体掉到水面一下太多会触发OnTriggerExit()(见脚本部分)。
//2.创建立方体
//创建一个长宽高分别为1，质量为0.5的立方体，预期效果是在水中漂浮一半露出水面。之后可以通过脚本改变大小及质量验证效果。
//3.水的脚本
//水的脚本主要实现OnTriggerEnter和OnTriggerExit两个方法，当其他碰撞体进入水中，触发OnTriggerEnter，将cube中的isInWater置为ture，OnTriggerExit相反。
//4.立方体脚本
//立方体脚本的核心是calFloatage方法，计算立方体下表面与水面高度差，通过公式计算浮力，并通过Rigidbody.AddForce()方法施加浮力。
//进入水中后将阻力系数调高。注意物体完全进入水中后保持h=立方体高度

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Floatage : MonoBehaviour {
	// Use this for initialization
	void Start () {
	}
	// Update is called once per frame
	void Update () {
	}
	/// <summary>
	/// OnTriggerEnter is called when the Collider other enters the trigger.
	/// </summary>
	/// <param name="other">The other Collider involved in this collision.</param>
	void OnTriggerEnter(Collider other)
	{	
		if(other.gameObject.GetComponent<Cube>()){
			other.gameObject.GetComponent<Cube>().setIsInWater(true);
		}
	}
	/// <summary>
	/// OnTriggerExit is called when the Collider other has stopped touching the trigger.
	/// </summary>
	/// <param name="other">The other Collider involved in this collision.</param>
	void OnTriggerExit(Collider other)
	{
		if(other.gameObject.GetComponent<Cube>()){
			other.gameObject.GetComponent<Cube>().setIsInWater(false);
		}
	}
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Cube : MonoBehaviour {
	private bool isInWater;
	private GameObject water;  
	private	 float waterY;
	private const float floatageForce = 0;
	private const float density = 1;
	private const float g = 9.8f;
	private const float waterDrag = 5;
	public bool getIsInWater(){
		return isInWater;
	}
	public void setIsInWater(bool isInWater){
		 this.isInWater = isInWater;
	}
	// Use this for initialization
	void Start () {
		isInWater = false;
		water = GameObject.FindWithTag("water");
	}
	// Update is called once per frame
	void Update () {
	}
	/// <summary>
	/// This function is called every fixed framerate frame, if the MonoBehaviour is enabled.
	/// </summary>
	void FixedUpdate()
	{
		if(isInWater){
			//calculate floatage
			calFloatage();
			//change darg
			GetComponent<Rigidbody>().drag = waterDrag;
		}
	}
		//calculate and add floatage force to the box.
		private void calFloatage(){
			waterY = water.transform.position.y;
			if(waterY>(transform.position.y-transform.localScale.y)){
				float h = waterY-(transform.position.y-transform.localScale.y/2)>transform.localScale.y? transform.localScale.y:waterY-(transform.position.y-transform.localScale.y/2);
				float floatageForce = density * g *transform.localScale.x*transform.localScale.z*h;
				GetComponent<Rigidbody>().AddForce(0,floatageForce,0);
			}
	}
}

https://gameinstitute.qq.com/community/detail/128724