Camera.projectionMatrix

# [Camera](https://docs.unity3d.com/cn/2019.4/ScriptReference/Camera.html).projectionMatrix

public [Matrix4x4](https://docs.unity3d.com/cn/2019.4/ScriptReference/Matrix4x4.html) **projectionMatrix** ;

## 描述

设置自定义投影矩阵。

如果更改该矩阵，摄像机将不再根据其 [fieldOfView](https://docs.unity3d.com/cn/2019.4/ScriptReference/Camera-fieldOfView.html) 更新渲染。 在调用 [ResetProjectionMatrix](https://docs.unity3d.com/cn/2019.4/ScriptReference/Camera.ResetProjectionMatrix.html) 之前，该设置持续有效。

仅在您确实需要非标准投影时，才使用自定义投影。 Unity 的水渲染使用该属性设置一个 *倾斜投影*矩阵。要使用自定义投影，您必须具备良好的 变换和投影矩阵知识。

注意，可以根据平台和其他状态修改 传递给着色器的投影矩阵。如果需要从摄像机投影计算 供着色器使用的投影矩阵，请使用 [GL.GetGPUProjectionMatrix](https://docs.unity3d.com/cn/2019.4/ScriptReference/GL.GetGPUProjectionMatrix.html)。

另请参阅：[Camera.nonJitteredProjectionMatrix](https://docs.unity3d.com/cn/2019.4/ScriptReference/Camera-nonJitteredProjectionMatrix.html)

```
// Make camera wobble in a funky way!
using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    public Matrix4x4 originalProjection;
    Camera cam;

void Start()
    {
        cam = GetComponent<Camera>();
        originalProjection = cam.projectionMatrix;
    }

void Update()
    {
        Matrix4x4 p = originalProjection;
        p.m01 += Mathf.Sin(Time.time * 1.2F) * 0.1F;
        p.m10 += Mathf.Sin(Time.time * 1.5F) * 0.1F;
        cam.projectionMatrix = p;
    }
}
```

```
// Set an off-center projection, where perspective's vanishing
// point is not necessarily in the center of the screen.
//
// left/right/top/bottom define near plane size, i.e.
// how offset are corners of camera's near plane.
// Tweak the values and you can see camera's frustum change.

using UnityEngine;
using System.Collections;

[ExecuteInEditMode]
public class ExampleClass : MonoBehaviour
{
    public float left = -0.2F;
    public float right = 0.2F;
    public float top = 0.2F;
    public float bottom = -0.2F;
    void LateUpdate()
    {
        Camera cam = Camera.main;
        Matrix4x4 m = PerspectiveOffCenter(left, right, bottom, top, cam.nearClipPlane, cam.farClipPlane);
        cam.projectionMatrix = m;
    }

static Matrix4x4 PerspectiveOffCenter(float left, float right, float bottom, float top, float near, float far)
    {
        float x = 2.0F * near / (right - left);
        float y = 2.0F * near / (top - bottom);
        float a = (right + left) / (right - left);
        float b = (top + bottom) / (top - bottom);
        float c = -(far + near) / (far - near);
        float d = -(2.0F * far * near) / (far - near);
        float e = -1.0F;
        Matrix4x4 m = new Matrix4x4();
        m[0, 0] = x;
        m[0, 1] = 0;
        m[0, 2] = a;
        m[0, 3] = 0;
        m[1, 0] = 0;
        m[1, 1] = y;
        m[1, 2] = b;
        m[1, 3] = 0;
        m[2, 0] = 0;
        m[2, 1] = 0;
        m[2, 2] = c;
        m[2, 3] = d;
        m[3, 0] = 0;
        m[3, 1] = 0;
        m[3, 2] = e;
        m[3, 3] = 0;
        return m;
    }
}
```