旋转矩阵公式推导

image.png image.png

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

public class VertexAnimalMatrix : MonoBehaviour {

float tmpFloat;

Mesh myMesh;

float timer;

Vector3[] myList;
void Start () {
    myMesh = transform.GetComponent<MeshFilter>().mesh;
    //for(int i=0;i< myMesh.vertices.Length; i++)
    //{
    //    myList[i] = myMesh.vertices[i];
    //}
    

}

void Update () {
    myList = myMesh.vertices;
    tmpFloat = Input.GetAxis("Horizontal");
    for (int i = 0; i < myMesh.vertices.Length; i++)
    {
        //这里旋转的层数不多是因为顶点少
        myList[i]= DoTwistX(tmpFloat* myList[i].x*0.1f, myList[i]);
    }
    myMesh.vertices = myList;
    //myMesh.SetVertices(DoTwistX(tmpFloat, gameObject.transform.position))

}
/// <summary>
/// 根据矩阵，围绕X轴旋转
/// </summary>
/// <param name="angle">要旋转的角度</param>
/// <param name="pos">obj的位置</param>
/// <returns></returns>
public Vector3 DoTwistX(float angle,Vector3 pos)
{
    float cos = Mathf.Cos(angle);

    float sin = Mathf.Sin(angle);

    Vector3 result = pos;

    result.y = pos.y * cos + pos.z * sin;

    result.z = pos.y * (-sin) + pos.z * cos;
    return result;
}
/// <summary>
/// 根据矩阵，围绕Y轴旋转
/// </summary>
/// <param name="angle">要旋转的角度</param>
/// <param name="pos">要旋转的obj的位置</param>
/// <returns></returns>
public Vector3 DoTwistY(float angle,Vector3 pos)
{
    float cos = Mathf.Cos(angle);
    float sin = Mathf.Sin(angle);

    Vector3 result = pos;

    result.x = pos.x * cos + pos.y * (-sin);

    result.z = pos.x * sin + pos.y * cos;
    return result;
}
/// <summary>
/// 根据矩阵，围绕Z轴旋转
/// </summary>
/// <param name="angle">要旋转的角度</param>
/// <param name="pos">要旋转的obj的位置</param>
/// <returns></returns>
public Vector3 DoTwistZ(float angle,Vector3 pos)
{
    float cos = Mathf.Cos(angle);
    float sin = Mathf.Sin(angle);

    Vector3 result = pos;

    result.x = pos.x * cos + pos.y * sin;
    result.y = pos.x * (-sin) + pos.y * cos;

    return result;
}

}