# OnPostRender()

> Event function that Unity calls after a Camera renders the scene.

## Definition

* **Type:** Method
* **Namespace:** [UnityEngine](/engine/6000.7/script-reference/unityengine.md)

```csharp
public void OnPostRender()
```

### Remarks

In the Built-in Render Pipeline, Unity calls `OnPostRender` on MonoBehaviours that are attached to the same GameObject as an enabled [Camera](/engine/6000.7/script-reference/unityengine/camera.md) component, just after that Camera renders the scene. Use `OnPostRender` to execute your own code at this point in the render loop; for example, if you changed a visual effect in [MonoBehaviour.OnPreRender()](/engine/6000.7/script-reference/unityengine/monobehaviour/onprerender.md), you can change it back here. `OnPostRender` can be a coroutine. For similar functionality that does not require the script to be on the same GameObject as a Camera component, see [Camera.onPostRender](/engine/6000.7/script-reference/unityengine/camera/onpostrender-1.md). **Note**: `OnPostRender` depends on the Built-in Render Pipeline and won't be called in projects using the Scriptable or Universal Render Pieplines. For similar functionality in the Scriptable Render Pipeline, refer to [RenderPipelineManager](/engine/6000.7/script-reference/unityengine/rendering/renderpipelinemanager.md). To execute code after Unity renders all Cameras and GUI, use [WaitForEndOfFrame](/engine/6000.7/script-reference/unityengine/waitforendofframe.md) or a [CommandBuffer](/engine/6000.7/script-reference/unityengine/rendering/commandbuffer.md).

```csharp
using UnityEngine;

// A script that when attached to the camera, makes the resulting
// colors inverted. See its effect in play mode.
public class ExampleClass : MonoBehaviour
{
    private Material mat;

    // Will be called from camera after regular rendering is done.
    public void OnPostRender()
    {
        if (!mat)
        {
            // Unity has a built-in shader that is useful for drawing
            // simple colored things. In this case, we just want to use
            // a blend mode that inverts destination colors.
            var shader = Shader.Find("Hidden/Internal-Colored");
            mat = new Material(shader);
            mat.hideFlags = HideFlags.HideAndDontSave;
            // Set blend mode to invert destination colors.
            mat.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusDstColor);
            mat.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
            // Turn off backface culling, depth writes, depth test.
            mat.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
            mat.SetInt("_ZWrite", 0);
            mat.SetInt("_ZTest", (int)UnityEngine.Rendering.CompareFunction.Always);
        }

        GL.PushMatrix();
        GL.LoadOrtho();

        // activate the first shader pass (in this case we know it is the only pass)
        mat.SetPass(0);
        // draw a quad over whole screen
        GL.Begin(GL.QUADS);
        GL.Vertex3(0, 0, 0);
        GL.Vertex3(1, 0, 0);
        GL.Vertex3(1, 1, 0);
        GL.Vertex3(0, 1, 0);
        GL.End();

        GL.PopMatrix();
    }
}
```

Additional Resources: [Camera.onPostRender](/engine/6000.7/script-reference/unityengine/camera/onpostrender-1.md), [MonoBehaviour.OnPreRender()](/engine/6000.7/script-reference/unityengine/monobehaviour/onprerender.md), [MonoBehaviour.OnPreCull()](/engine/6000.7/script-reference/unityengine/monobehaviour/onprecull.md), [CommandBuffer](/engine/6000.7/script-reference/unityengine/rendering/commandbuffer.md), [Extending the Built-in Render Pipeline using CommandBuffers](/engine/6000.7/manual/render-pipelines/built-in-render-pipeline/graphics-command-buffers/buffers.md), [WaitForEndOfFrame](/engine/6000.7/script-reference/unityengine/waitforendofframe.md).