using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class VerletParticle
{
    public Vector3 position;           // 当前帧位置
    public Vector3 previousPosition;   // 上一帧位置

    public float mass = 1f; // 默认质量
    public bool isLocked;              // 是否锁定

    public VerletParticle(Vector3 position)
    {
        this.position = position;
        this.previousPosition = position;  // 初始时，上一帧的位置与当前相同
        this.isLocked = false;             // 默认粒子不锁定
    }

    // Apply force to the particle (affects velocity)
    public void ApplyForce(Vector3 force)
    {
        if (!isLocked)
        {
            Vector3 velocity = position - previousPosition;
            Vector3 airResistance = -velocity * 0.3f;
            //Vector3 damping = velocity * 0.02f;  // 额外的速度衰减
            velocity += (force + airResistance) * Time.deltaTime / mass;  // 考虑质量
            previousPosition = position;
            position += velocity;
        }
    }



    // Update the particle's position using Verlet integration
    public void UpdatePosition()
    {
        if (!isLocked)
        {
            Vector3 velocity = position - previousPosition;  // 计算当前速度
            previousPosition = position;  // 更新上一帧位置
            position += velocity;  // 用速度更新当前位置
        }
    }
}