How to apply MPSImageGuidedFilter in Swift - ios

Question

I applied OpenCV guided filter for my project in Python successfully and now I have to carry this function to my iOS application. I searched Apple developer website and found out a filter called MPSImageGuidedFilter. I suppose it works in a similar way as OpenCV guided filter. However, my limited knowledge of iOS programming does not let me figure out how to use it. Unfortunately, I could not find a sample code on the web too. Is there anyone who used this filter before? I really appreciate the help. Or a sample code using any filter under MPS would be helpful to figure out.

Answer 1

After a few days of hard work, I managed to make MPSImageGUidedFilter. Please see below the code who wants to work on:
import UIKit
import MetalPerformanceShaders
import MetalKit
class ViewController: UIViewController {
public var texIn: MTLTexture!
public var coefficient: MTLTexture!
public var context: CIContext!
let device = MTLCreateSystemDefaultDevice()!
var queue: MTLCommandQueue!
var Metalview: MTKView { return view as! MTKView }
override func viewDidLoad() {
super.viewDidLoad()
Metalview.drawableSize.height = 412
Metalview.drawableSize.width = 326
Metalview.framebufferOnly = false
Metalview.device = device
Metalview.delegate = self
queue = device.makeCommandQueue()
let textureLoader = MTKTextureLoader(device: device)
let urlCoeff = Bundle.main.url(forResource: "mask", withExtension: "png")
do {
coefficient = try textureLoader.newTexture(URL: urlCoeff!, options: [:])
} catch {
fatalError("coefficient file not uploaded")
}
let url = Bundle.main.url(forResource: "guide", withExtension: "png")
do {
texIn = try textureLoader.newTexture(URL: url!, options: [:])
} catch {
fatalError("resource file not uploaded")
}
}
}
extension ViewController: MTKViewDelegate {
func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {}
func draw(in view: MTKView) {
guard let commandBuffer = queue.makeCommandBuffer(),
let drawable = view.currentDrawable else {
return
}
let shader = MPSImageGuidedFilter(device: device, kernelDiameter: 5)
shader.epsilon = 0.001
let textOut = drawable.texture
shader.encodeReconstruction(to: commandBuffer, guidanceTexture: texIn, coefficientsTexture: coefficient, destinationTexture: textOut)
commandBuffer.present(drawable)
commandBuffer.commit()
}
}