# Perspective(float, float, float, float)

> Create a perspective projection matrix.

## Definition

* **Type:** Method
* **Namespace:** [UnityEngine](/engine/6000.0/script-reference/unityengine.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
public static Matrix4x4 Perspective(float fov, float aspect, float zNear, float zFar)
```

### Parameters

**** (\[float]\(https\://learn.microsoft.com/dotnet/api/system.single)): Vertical field-of-view in degrees.**** (\[float]\(https\://learn.microsoft.com/dotnet/api/system.single)): Aspect ratio (width divided by height).**** (\[float]\(https\://learn.microsoft.com/dotnet/api/system.single)): Near depth clipping plane value.**** (\[float]\(https\://learn.microsoft.com/dotnet/api/system.single)): Far depth clipping plane value.

### Returns

| Type                                                                  | Description            |
| --------------------------------------------------------------------- | ---------------------- |
| [Matrix4x4](/engine/6000.0/script-reference/unityengine/matrix4x4.md) | The projection matrix. |

### Remarks

Projection matrices in Unity follow [OpenGL](https://en.wikipedia.org/wiki/OpenGL) convention, i.e. clip space near plane is at `z=-1`, and far plane is at `z=1`.

The returned matrix embeds a z-flip operation whose purpose is to cancel the z-flip performed by the camera view matrix. If the view matrix is an identity or some custom matrix that doesn't perform a z-flip, consider multiplying the third column of the projection matrix (i.e. m02, m12, m22 and m32) by -1.

Note that depending on the graphics API used, projection matrices in shaders can follow different convention, for example the D3D-style clip space has near plane at zero and far plane at one; and "reversed Z" projection has near plane at one and far plane at zero. To calculate projection matrix value suitable for passing to shader variables, use [GL.GetGPUProjectionMatrix](/engine/6000.0/script-reference/unityengine/gl/getgpuprojectionmatrix.md).

```csharp
using UnityEngine;

public class ExampleScript : MonoBehaviour
{
    void Start()
    {
        // create projection matrix: 60 FOV, square aspect,
        // near plane 1, far plane 100
        var matrix = Matrix4x4.Perspective(60, 1, 1, 100);
        // will print:
        // 0.20000 0.00000  0.00000  0.00000
        // 0.00000 0.20000  0.00000  0.00000
        // 0.00000 0.00000 -0.02020 -1.02020
        // 0.00000 0.00000  0.00000  1.00000
        Debug.Log("projection matrix\n" + matrix);

        // get shader-compatible projection matrix value
        var shaderMatrix = GL.GetGPUProjectionMatrix(matrix, false);
        // on a Direct3D-like graphics API, will print:
        // 0.20000 0.00000 0.00000 0.00000
        // 0.00000 0.20000 0.00000 0.00000
        // 0.00000 0.00000 0.01010 1.01010
        // 0.00000 0.00000 0.00000 1.00000
        Debug.Log("shader projection matrix\n" + shaderMatrix);
    }
}
```

Additional Resources: [Matrix4x4.Ortho](/engine/6000.0/script-reference/unityengine/matrix4x4/ortho.md), [Camera.projectionMatrix](/engine/6000.0/script-reference/unityengine/camera/projectionmatrix.md), [GL.LoadPixelMatrix](/engine/6000.0/script-reference/unityengine/gl/loadpixelmatrix.md), [GL.LoadProjectionMatrix](/engine/6000.0/script-reference/unityengine/gl/loadprojectionmatrix.md), [GL.GetGPUProjectionMatrix](/engine/6000.0/script-reference/unityengine/gl/getgpuprojectionmatrix.md).