Unity 相机 2D视角 与3D 视角 自由动态 切换

再游戏运行的时候，往往需要 在 正交Orthographic (无消失点投影) 与正交Orthographic (无消失点投影) 两个视角中来回转化。 以达到 不同的 2D 与 3D 视角。

So! 今天的 实例代码就是 描述了 这一个功能：

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using UnityEngine;public enum Views{    _2DView = 1,    _3DView} public class BackupCameraProjectionChange {    /// <summary>    /// 相机透视改变是否触发(调用只需把此值改为true)    /// </summary>    public bool ChangeProjection = false;    private bool _changing = false;    private float ProjectionChangeTime = 0.5f;    private float _currentT = 0.0f;    private Camera m_Camera;protected Views cur_Views = Views._3DView;public Views GetCurViews{    get    {        return cur_Views;    }}public BackupCameraProjectionChange(Camera camera = null , float speed = 0.5f){    ProjectionChangeTime = speed;    if (m_Camera == null && camera == null)    {        m_Camera = Camera.main;    }    else    {        m_Camera = camera;    }}///这个 Update 需要在 其他继承自 MonoBehaviour 类的 Update 中 调用public void Update(){    if (m_Camera == null)        return;    if (_changing)    {        ChangeProjection = false;    }    else if (ChangeProjection)    {        _changing = true;        _currentT = 0.0f;    }    LateUpdate();}void LateUpdate(){    if (!_changing)    {        return;    }    //将当前的 是否正视图值 赋值给currentlyOrthographic变量    bool currentlyOrthographic = m_Camera.orthographic;    //定义变量存放当前摄像机的透视和正视矩阵信息；    Matrix4x4 orthoMat, persMat;    if (currentlyOrthographic)//如果当前摄像机为正视状态，则切换为3D    {        orthoMat = m_Camera.projectionMatrix; //保留 2D矩阵信息        m_Camera.orthographic = false;  //为 3D        m_Camera.ResetProjectionMatrix();        persMat = m_Camera.projectionMatrix;   //保留 3D 矩阵信息        cur_Views = Views._3DView;    }    else//否则当前摄像机为透视状态， 则切换为2D    {        persMat = m_Camera.projectionMatrix; //保留 3D 矩阵信息        m_Camera.orthographic = true;    //为2D        m_Camera.ResetProjectionMatrix();        orthoMat = m_Camera.projectionMatrix;  //保留 2D矩阵信息        cur_Views = Views._2DView;    }    m_Camera.orthographic = currentlyOrthographic;    _currentT += (Time.deltaTime / ProjectionChangeTime);    if (_currentT < 1.0f)    {        if (currentlyOrthographic)        {            m_Camera.projectionMatrix = MatrixLerp(orthoMat, persMat, _currentT * _currentT);  //从2D 到 3D        }        else        {            m_Camera.projectionMatrix = MatrixLerp(persMat, orthoMat, Mathf.Sqrt(_currentT)); //从3D 到 2D        }    }    else    {        _changing = false;        m_Camera.orthographic = !currentlyOrthographic;  //取反        m_Camera.ResetProjectionMatrix();   // 重置    }}private Matrix4x4 MatrixLerp(Matrix4x4 from, Matrix4x4 to, float t){    t = Mathf.Clamp(t, 0.0f, 1.0f);    Matrix4x4 newMatrix = new Matrix4x4();    newMatrix.SetRow(0, Vector4.Lerp(from.GetRow(0), to.GetRow(0), t));    newMatrix.SetRow(1, Vector4.Lerp(from.GetRow(1), to.GetRow(1), t));    newMatrix.SetRow(2, Vector4.Lerp(from.GetRow(2), to.GetRow(2), t));    newMatrix.SetRow(3, Vector4.Lerp(from.GetRow(3), to.GetRow(3), t));    return newMatrix;}}

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