unity 单摆模拟
using System;
using UnityEngine;
using System.Collections;
using UnityEngine.Serialization;
public class Pendulum : MonoBehaviour {
public Transform anchor; // 圆点
public float g = 9.8f; // 重力加速度
private float m_w = 0f; // 角速度(单位：弧度/秒)
private float m_l; // 摆长
private void Start() {
m_l = Vector3.Distance(anchor.position, transform.position);
}
private void Update() {
float x = transform.position.x - anchor.position.x;
float sinAlpha = x / m_l;
// 求角加速度
float a = -(sinAlpha * g) / m_l;
// 累计角速度(单位：弧度/秒)
m_w += a * Time.deltaTime;
// 求角位移(乘以 Mathf.Rad2Deg 是为了将弧度转换为角度)
float thelta = m_w * Time.deltaTime * Mathf.Rad2Deg;
// 绕圆点ahchor的旋转轴Vector3.back旋转thelta角度
transform.RotateAround(anchor.position, Vector3.back, -thelta);
}
}
自定义旋转轴:
using System;
using UnityEngine;
using System.Collections;
using UnityEngine.Serialization;
public class Pendulum : MonoBehaviour {
public Transform anchor; // 圆点
public float g = 9.8f; // 重力加速度
private float m_w = 0; // 角速度(单位：弧度/秒)
private float m_l; // 摆长
private Vector3 m_rotateAxis; // 旋转轴
private void Start() {
// 求出旋转轴
m_rotateAxis = Vector3.Cross(transform.position - anchor.position, Vector3.down);
// 求摆长
m_l = Vector3.Distance(anchor.position, transform.position);
}
private void Update() {
float d = Vector3.Distance(new Vector3(anchor.position.x, transform.position.y, anchor.position.z), transform.position);
// 当钟摆摆动到另外一侧时，d为负，则角加速度a为负。
Vector3 axis = Vector3.Cross(transform.position - anchor.position, Vector3.down);
if (Vector3.Dot(axis, m_rotateAxis) < 0) {
d = -d;
}
float sinAlpha = d / m_l;
// 求角加速度
float a = (sinAlpha * g) / m_l;
// 累计角速度(单位：弧度/秒)
m_w += a * Time.deltaTime;
// 求角位移(乘以 Mathf.Rad2Deg 是为了将弧度转换为角度)
float thelta = m_w * Time.deltaTime * Mathf.Rad2Deg;
// 绕圆点ahchor的旋转轴m_rotateAxis旋转thelta角度
transform.RotateAround(anchor.position, m_rotateAxis, thelta);
}
}
https://www.bilibili.com/video/BV19M411k7A7/?spm_id_from=333.337.search-card.all.click&vd_source=5672eeb8a9721da01495e313f0dff6c2
https://zhuanlan.zhihu.com/p/147657140
