Matrix4x4.inverse

描述

此矩阵的逆矩阵。（只读）

逆矩阵与原始矩阵相乘可得到 identity 矩阵。

如果某个矩阵以特定方式变换矢量， 则逆矩阵可以将其变换还原。例如， Transform 的 worldToLocalMatrix 和 localToWorldMatrix 是彼此的逆矩阵。

对于常规 3D 变换矩阵，使用 Inverse3DAffine 方法可能会更快。

无法对 determinant 为零的矩阵求逆。 如果尝试此操作，则 inverse 会改为返回 Matrix4x4.zero。

using UnityEngine;

// Stretch a mesh at an arbitrary angle around the X axis
[RequireComponent(typeof(MeshFilter))]
public class ExampleScript : MonoBehaviour
{
    // Angle and amount of stretching
    public float rotAngle = 30;
    public float stretch = 3;


    MeshFilter mf;
    Vector3[] origVerts;
    Vector3[] newVerts;

    void Start()
    {
        // Get the Mesh Filter component, save its original vertices
        // and make a new vertex array for processing.
        mf = GetComponent<MeshFilter>();
        origVerts = mf.mesh.vertices;
        newVerts = new Vector3[origVerts.Length];
    }

    void Update()
    {
        // Create a rotation matrix from a Quaternion
        Quaternion rot = Quaternion.Euler(rotAngle, 0, 0);
        Matrix4x4 m = Matrix4x4.TRS(Vector3.zero, rot, Vector3.one);

        // Get the inverse of the matrix: undo the rotation
        Matrix4x4 inv = m.inverse;

        // For each vertex:
        for (var i = 0; i < origVerts.Length; i++)
        {
            // Rotate the vertex and scale it along its new Y axis
            Vector3 pt = m.MultiplyPoint3x4(origVerts[i]);
            pt.y *= stretch;

            // Return the vertex to its original rotation (but with the
            // scaling still applied).
            newVerts[i] = inv.MultiplyPoint3x4(pt);
        }

        // Assign the transformed vertices to the mesh
        mf.mesh.vertices = newVerts;
    }
}

另请参阅：Inverse3DAffine、determinant。