# postProcess A callback function for implementing postprocess effects. ``` var postProcess: ((ARView.PostProcessContext) -> Void)? ``` ## Discussion Assign a function or closure to this property to implement postprocessing effects for a RealityKit scene. If this value is non-`nil`, RealityKit calls the assigned function or closure once every frame before it displays the scene. If you register a postprocess render callback, the callback function needs to encode the modified frame buffer to the context’s [`targetColorTexture`](/documentation/RealityKit/ARView/PostProcessContext/targetColorTexture), or nothing renders. A postprocess callback looks like this: ```swift func myPostProcessCallback(context:ARView.PostProcessContext) { // Handle postprocessing here. } ``` To register the function so RealityKit begins calling it, assign it to the [`postProcess`](/documentation/RealityKit/ARView/RenderCallbacks-swift.struct/postProcess) property of the view’s [`renderCallbacks`](/documentation/RealityKit/ARView/renderCallbacks-swift.property) property. ```swift arView.renderCallbacks.postProcess = myPostProcessCallback ``` To stop RealityKit from calling your function, assign `nil`: ```swift arView.renderCallbacks.postProcess = nil ``` If your app turns postprocessing on and off frequently, another option for disabling postprocess effects is to keep your callback registered, but use an to encode the unmodified frame directly to the output texture whenever postprocess effects aren’t active. ```swift func myPostProcessCallback(context:ARView.PostProcessContext) { if (usePostProcessEffects) { handlePostProcessing(context: ARView.PostProcessContext) return } // If postprocess effects are disabled, copy sourceColorTexture // directly to targetColorTexture. let blitEncoder = context.commandBuffer.makeBlitCommandEncoder() blitEncoder?.copy(from: context.sourceColorTexture, to: context.targetColorTexture) blitEncoder?.endEncoding() } ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)