ARKitCameraFeedFilter

This project is a basic example of applying a Black & White Filter to the camera feed on an ARSession.

Note that this does not render virtual content in Black & White, only the camera feed itself.

All the code is fully commented so the apps functionality should be clear to everyone.

Branches:

The Master Branch was originally compiled in XCode10 Beta using Swift 4.

An updated Branch called 'Swift4.2' contains the project built in XCode 10.5 Beta and uses Swift 4.2.

Requirements:

The project is setup for iPhone, and in Portait Orientation.

Core Functionality:

The demo project allows you to toggle the colour of the camera feed using a UISegmentedControl.

The way in which the camera feed is rendered in Black & White is achieved by manipulating the CVPixelBuffer within the sessions didUpdateFrame delegate callback:

func session(_ session: ARSession, didUpdate frame: ARFrame) {
    
    //Convert The Current Frame To Black & White
    guard let currentBackgroundFrameImage = augmentedRealityView.session.currentFrame?.capturedImage,
          let pixelBufferAddressOfPlane = CVPixelBufferGetBaseAddressOfPlane(currentBackgroundFrameImage, 1) else { return }
    
    let x: size_t = CVPixelBufferGetWidthOfPlane(currentBackgroundFrameImage, 1)
    let y: size_t = CVPixelBufferGetHeightOfPlane(currentBackgroundFrameImage, 1)
    memset(pixelBufferAddressOfPlane, 128, Int(x * y) * 2)
    
}

Considerations:

In order to render all SceneKit content in Black & White, you can look at using the following:

1. SCNTechnique: which is a specification for augmenting or postprocessing SceneKit's rendering of a scene using additional drawing passes with custom Metal or OpenGL shaders.
2. Using the filters property of an SCNNode which is simply an array of CoreImage filters to be applied to the rendered contents of the node.