MasDennis

guard let computePipelineState = self.computePipelineState,
      let encoder = context.commandBuffer.makeComputeCommandEncoder()
else {
    return
}

encoder.setComputePipelineState(computePipelineState)
encoder.setTexture(context.sourceColorTexture, index: 0)
encoder.setTexture(context.targetColorTexture, index: 1)
encoder.dispatchThreadgroups(self.threadgroupsPerGrid, threadsPerThreadgroup: self.threadsPerThreadgroup)

MasDennis

private func setupComputePipeline(targetTexture: MTLTexture) {
    guard let device = MTLCreateSystemDefaultDevice(),
          let library = device.makeDefaultLibrary(),
          let postProcessingKernel = library.makeFunction(name: "inverseColorKernel"),
          let pipelineState = try? device.makeComputePipelineState(function: postProcessingKernel)
    else {
        assertionFailure()
        return
    }

MasDennis

let device = MTLCreateSystemDefaultDevice()
let library = device.makeDefaultLibrary()
let postProcessingKernel = library.makeFunction(name: "inverseColorKernel")
let pipelineState = try? device.makeComputePipelineState(function: postProcessingKernel)

MasDennis

#include <metal_stdlib>
using namespace metal;

[[kernel]]
void inverseColorKernel(texture2d<float, access::read> sourceTexture [[texture(0)]],
                        texture2d<float, access::write> targetTexture [[texture(1)]],
                        uint2 gridPosition [[thread_position_in_grid]])
{
    float4 sourceColor = sourceTexture.read(gridPosition);
    float4 inverseColor = float4(1.0 - sourceColor.rgb, sourceColor.a);

MasDennis

arView.renderCallbacks.postProcess = { [weak self] context in
  // ... post-processing code ...
}

MasDennis

//
//  LoopAndGestureViewController.swift
//  
//
//  Created by Dennis Ippel on 02/04/2021.
//

import UIKit
import RealityKit
import Combine

MasDennis

import UIKit
import RealityKit
import Combine

class GameViewController: UIViewController {
    
    var sceneEventsUpdateSubscription: Cancellable!
    
    override func viewDidLoad() {
        super.viewDidLoad()

MasDennis

struct FragmentOut {
    float4 color [[color(0)]];
    float depth [[depth(any)]];
};

fragment FragmentOut screenQuadFragment(ScreenQuadVertex inVertex [[stage_in]],
                                        texture2d<uint, access::sample> segmentationTexture [[texture(0)]],
                                        constant Uniforms& uniforms [[buffer(0)]])
{
    FragmentOut out;

MasDennis

constant float4x4 quadVertices = float4x4(float4( -1.0, -1.0, 0.0, 1.0 ),
                                          float4(  1.0, -1.0, 0.0, 1.0 ),
                                          float4( -1.0,  1.0, 0.0, 1.0 ),
                                          float4(  1.0,  1.0, 0.0, 1.0 ));

constant float4x2 quadTextureCoordinates = float4x2(float2( 1.0, 1.0 ),
                                                    float2( 0.0, 1.0 ),
                                                    float2( 1.0, 0.0 ),
                                                    float2( 0.0, 0.0 ));

MasDennis

let viewBoundingBox = viewSpaceBoundingBox(fromNormalizedImageBoundingBox: boundingBox,
                                           usingDisplayTransform: displayTransform)
        
let midPoint = CGPoint(x: viewBoundingBox.midX,
                       y: viewBoundingBox.midY)

// Get the feature point that is closed to our detected rectangle's center
let results = sceneView.hitTest(midPoint, types: .featurePoint)

let depthBufferZ = calculateFragmentDepth(usingCamera: camera,