GPUImage2 , Switching between Front and back Camera

Question

How to rotate or switch between front and back camera in GPUImage2(Switch version) using swift (toggle with a button). Any help would be highly appreciated.Thank you in advance.

Answer 1

Let's consider the main example of GPUImage2 :

do {
    camera = try Camera(sessionPreset:AVCaptureSessionPreset640x480)
    filter = SaturationAdjustment()
    camera --> filter --> renderView
    camera.startCapture()
} catch {
    fatalError("Could not initialize rendering pipeline: \(error)")
}

Once your camera started capturing, you can switch from back to front this way :

do {

    // Stop the capture of the current camera and remove its targets
    sharedImageProcessingContext.runOperationSynchronously{
        camera.stopCapture()
        camera.removeAllTargets()
    }

    // Build a new Camera object, using the back or front physical camera
    if camera.location == .frontFacing {
        camera = try Camera(sessionPreset:.vga640x480, location:.backFacing)
    } else {
        camear = try Camera(sessionPreset:.vga640x480, location:.frontFacing)
    }

    //Rebuild the pipeline
    camera --> filter --> renderView
    camera.startCapture()

} catch {
    print("Error switching camera : \(error)")
}

Side note #1 : The default camera used is the back one, as implied by the default values of Camera.init() :

public init(sessionPreset:AVCaptureSession.Preset, 
             cameraDevice:AVCaptureDevice? = nil, 
                 location:PhysicalCameraLocation = .backFacing, 
...

Side note #2 : the Camera object presents the location property. Unfortunately, its didSet accessor is still in "TODO" :

public var location:PhysicalCameraLocation {
    didSet {
        // TODO: Swap the camera locations, framebuffers as needed
    }
}