RealityKit Postprocess Filter

引入CoreImage

import CoreImage
import CoreImage.CIFilterBuiltins

确保输出材质采用设备支持的像素格式

extension RealityKit.ARView.PostProcessContext {
    /// Returns the output texture, ensuring that the pixel format is appropriate for the current device's GPU.
    var compatibleTargetTexture: MTLTexture! {
        if self.device.supportsFamily(.apple2) {
            return targetColorTexture
        } else {
            return targetColorTexture.makeTextureView(pixelFormat: .bgra8Unorm)!
        }
    }
}

声明一个CIContext

var ciContext: CIContext!

注册回调函数

    func setupPostprocess() {
        arView.renderCallbacks.prepareWithDevice = setupCoreImage(device:)
        arView.renderCallbacks.postProcess = postProcessWithCoreImage(context:)
    }

RealityKit加载完成在渲染第一帧前会调用prepareWithDevice一次, 可在此做耗时操作

    func setupCoreImage(device: MTLDevice) {
        // Create a CIContext and store it in a property.
        ciContext = CIContext(mtlDevice: device)

        // Do other expensive tasks, like loading images, here.
    }

展示到屏幕之前每帧都会调用, 拒绝耗时操作

    func postProcessWithCoreImage(context: ARView.PostProcessContext) {

        // Create and configure the Core Image filter.
        let filter = CIFilter.gammaAdjust()
        filter.power = 4

        // Convert the frame buffer from a Metal texture to a CIImage, and
        // set the CIImage as the filter's input image.
        guard let input = CIImage(mtlTexture: context.sourceColorTexture) else {
            fatalError("Unable to create a CIImage from sourceColorTexture.")
        }
        filter.setValue(input, forKey: kCIInputImageKey)

        // Get a reference to the filter's output image.
        guard let output = filter.outputImage else {
            fatalError("Error applying filter.")
        }

        // Create a render destination and render the filter to the context's command buffer.
        let destination = CIRenderDestination(mtlTexture: context.compatibleTargetTexture,
                                              commandBuffer: context.commandBuffer)
        destination.isFlipped = false
        _ = try? self.ciContext.startTask(toRender: output, to: destination)
    }

苹果提供了十分多的filter

@available(iOS 13.0, *)
extension CIFilter {

    
    // CICategoryGradient
    open class func gaussianGradient() -> CIFilter & CIGaussianGradient

    open class func hueSaturationValueGradient() -> CIFilter & CIHueSaturationValueGradient

    open class func linearGradient() -> CIFilter & CILinearGradient

    open class func radialGradient() -> CIFilter & CIRadialGradient

    open class func smoothLinearGradient() -> CIFilter & CISmoothLinearGradient

    
    // CICategorySharpen
    open class func sharpenLuminance() -> CIFilter & CISharpenLuminance

    open class func unsharpMask() -> CIFilter & CIUnsharpMask

    
    // CICategoryHalftoneEffect
    open class func circularScreen() -> CIFilter & CICircularScreen

    open class func cmykHalftone() -> CIFilter & CICMYKHalftone

    open class func dotScreen() -> CIFilter & CIDotScreen

    open class func hatchedScreen() -> CIFilter & CIHatchedScreen

    open class func lineScreen() -> CIFilter & CILineScreen

    
    // CICategoryGeometryAdjustment
    open class func bicubicScaleTransform() -> CIFilter & CIBicubicScaleTransform

    open class func edgePreserveUpsample() -> CIFilter & CIEdgePreserveUpsample

    open class func keystoneCorrectionCombined() -> CIFilter & CIKeystoneCorrectionCombined

    open class func keystoneCorrectionHorizontal() -> CIFilter & CIKeystoneCorrectionHorizontal

    open class func keystoneCorrectionVertical() -> CIFilter & CIKeystoneCorrectionVertical

    open class func lanczosScaleTransform() -> CIFilter & CILanczosScaleTransform

    open class func perspectiveCorrection() -> CIFilter & CIPerspectiveCorrection

    open class func perspectiveRotate() -> CIFilter & CIPerspectiveRotate

    open class func perspectiveTransform() -> CIFilter & CIPerspectiveTransform

    open class func perspectiveTransformWithExtent() -> CIFilter & CIPerspectiveTransformWithExtent

    open class func straighten() -> CIFilter & CIStraighten

    
    // CICategoryTransition
    open class func accordionFoldTransition() -> CIFilter & CIAccordionFoldTransition

    open class func barsSwipeTransition() -> CIFilter & CIBarsSwipeTransition

    open class func copyMachineTransition() -> CIFilter & CICopyMachineTransition

    open class func disintegrateWithMaskTransition() -> CIFilter & CIDisintegrateWithMaskTransition

    open class func dissolveTransition() -> CIFilter & CIDissolveTransition

    open class func flashTransition() -> CIFilter & CIFlashTransition

    open class func modTransition() -> CIFilter & CIModTransition

    open class func pageCurlTransition() -> CIFilter & CIPageCurlTransition

    open class func pageCurlWithShadowTransition() -> CIFilter & CIPageCurlWithShadowTransition

    open class func rippleTransition() -> CIFilter & CIRippleTransition

    open class func swipeTransition() -> CIFilter & CISwipeTransition

    
    // CICategoryCompositeOperation
    open class func additionCompositing() -> CIFilter & CICompositeOperation

    open class func colorBlendMode() -> CIFilter & CICompositeOperation

    open class func colorBurnBlendMode() -> CIFilter & CICompositeOperation

    open class func colorDodgeBlendMode() -> CIFilter & CICompositeOperation

    open class func darkenBlendMode() -> CIFilter & CICompositeOperation

    open class func differenceBlendMode() -> CIFilter & CICompositeOperation

    open class func divideBlendMode() -> CIFilter & CICompositeOperation

    open class func exclusionBlendMode() -> CIFilter & CICompositeOperation

    open class func hardLightBlendMode() -> CIFilter & CICompositeOperation

    open class func hueBlendMode() -> CIFilter & CICompositeOperation

    open class func lightenBlendMode() -> CIFilter & CICompositeOperation

    open class func linearBurnBlendMode() -> CIFilter & CICompositeOperation

    open class func linearDodgeBlendMode() -> CIFilter & CICompositeOperation

    @available(iOS 15.0, *)
    open class func linearLightBlendMode() -> CIFilter & CICompositeOperation

    open class func luminosityBlendMode() -> CIFilter & CICompositeOperation

    open class func maximumCompositing() -> CIFilter & CICompositeOperation

    open class func minimumCompositing() -> CIFilter & CICompositeOperation

    open class func multiplyBlendMode() -> CIFilter & CICompositeOperation

    open class func multiplyCompositing() -> CIFilter & CICompositeOperation

    open class func overlayBlendMode() -> CIFilter & CICompositeOperation

    open class func pinLightBlendMode() -> CIFilter & CICompositeOperation

    open class func saturationBlendMode() -> CIFilter & CICompositeOperation

    open class func screenBlendMode() -> CIFilter & CICompositeOperation

    open class func softLightBlendMode() -> CIFilter & CICompositeOperation

    open class func sourceAtopCompositing() -> CIFilter & CICompositeOperation

    open class func sourceInCompositing() -> CIFilter & CICompositeOperation

    open class func sourceOutCompositing() -> CIFilter & CICompositeOperation

    open class func sourceOverCompositing() -> CIFilter & CICompositeOperation

    open class func subtractBlendMode() -> CIFilter & CICompositeOperation

    @available(iOS 15.0, *)
    open class func vividLightBlendMode() -> CIFilter & CICompositeOperation

    
    // CICategoryColorAdjustment
    @available(iOS 14.0, *)
    open class func colorAbsoluteDifference() -> CIFilter & CIColorAbsoluteDifference

    open class func colorClamp() -> CIFilter & CIColorClamp

    open class func colorControls() -> CIFilter & CIColorControls

    open class func colorMatrix() -> CIFilter & CIColorMatrix

    open class func colorPolynomial() -> CIFilter & CIColorPolynomial

    @available(iOS 14.0, *)
    open class func colorThreshold() -> CIFilter & CIColorThreshold

    @available(iOS 14.0, *)
    open class func colorThresholdOtsu() -> CIFilter & CIColorThresholdOtsu

    open class func depthToDisparity() -> CIFilter & CIDepthToDisparity

    open class func disparityToDepth() -> CIFilter & CIDisparityToDepth

    open class func exposureAdjust() -> CIFilter & CIExposureAdjust

    open class func gammaAdjust() -> CIFilter & CIGammaAdjust

    open class func hueAdjust() -> CIFilter & CIHueAdjust

    open class func linearToSRGBToneCurve() -> CIFilter & CILinearToSRGBToneCurve

    open class func sRGBToneCurveToLinear() -> CIFilter & CISRGBToneCurveToLinear

    open class func temperatureAndTint() -> CIFilter & CITemperatureAndTint

    open class func toneCurve() -> CIFilter & CIToneCurve

    open class func vibrance() -> CIFilter & CIVibrance

    open class func whitePointAdjust() -> CIFilter & CIWhitePointAdjust

    
    // CICategoryColorEffect
    open class func colorCrossPolynomial() -> CIFilter & CIColorCrossPolynomial

    open class func colorCube() -> CIFilter & CIColorCube

    open class func colorCubesMixedWithMask() -> CIFilter & CIColorCubesMixedWithMask

    open class func colorCubeWithColorSpace() -> CIFilter & CIColorCubeWithColorSpace

    open class func colorCurves() -> CIFilter & CIColorCurves

    open class func colorInvert() -> CIFilter & CIColorInvert

    open class func colorMap() -> CIFilter & CIColorMap

    open class func colorMonochrome() -> CIFilter & CIColorMonochrome

    open class func colorPosterize() -> CIFilter & CIColorPosterize

    @available(iOS 16.0, *)
    open class func convertLabToRGB() -> CIFilter & CIConvertLab

    @available(iOS 16.0, *)
    open class func convertRGBtoLab() -> CIFilter & CIConvertLab

    open class func dither() -> CIFilter & CIDither

    open class func documentEnhancer() -> CIFilter & CIDocumentEnhancer

    open class func falseColor() -> CIFilter & CIFalseColor

    open class func labDeltaE() -> CIFilter & CILabDeltaE

    open class func maskToAlpha() -> CIFilter & CIMaskToAlpha

    open class func maximumComponent() -> CIFilter & CIMaximumComponent

    open class func minimumComponent() -> CIFilter & CIMinimumComponent

    open class func paletteCentroid() -> CIFilter & CIPaletteCentroid

    open class func palettize() -> CIFilter & CIPalettize

    open class func photoEffectChrome() -> CIFilter & CIPhotoEffect

    open class func photoEffectFade() -> CIFilter & CIPhotoEffect

    open class func photoEffectInstant() -> CIFilter & CIPhotoEffect

    open class func photoEffectMono() -> CIFilter & CIPhotoEffect

    open class func photoEffectNoir() -> CIFilter & CIPhotoEffect

    open class func photoEffectProcess() -> CIFilter & CIPhotoEffect

    open class func photoEffectTonal() -> CIFilter & CIPhotoEffect

    open class func photoEffectTransfer() -> CIFilter & CIPhotoEffect

    open class func sepiaTone() -> CIFilter & CISepiaTone

    open class func thermal() -> CIFilter & CIThermal

    open class func vignette() -> CIFilter & CIVignette

    open class func vignetteEffect() -> CIFilter & CIVignetteEffect

    open class func xRay() -> CIFilter & CIXRay

    
    // CICategoryDistortionEffect
    @available(iOS 14.0, *)
    open class func bumpDistortion() -> CIFilter & CIBumpDistortion

    @available(iOS 14.0, *)
    open class func bumpDistortionLinear() -> CIFilter & CIBumpDistortionLinear

    @available(iOS 14.0, *)
    open class func circleSplashDistortion() -> CIFilter & CICircleSplashDistortion

    @available(iOS 14.0, *)
    open class func circularWrap() -> CIFilter & CICircularWrap

    @available(iOS 14.0, *)
    open class func displacementDistortion() -> CIFilter & CIDisplacementDistortion

    @available(iOS 14.0, *)
    open class func droste() -> CIFilter & CIDroste

    @available(iOS 14.0, *)
    open class func glassDistortion() -> CIFilter & CIGlassDistortion

    @available(iOS 14.0, *)
    open class func glassLozenge() -> CIFilter & CIGlassLozenge

    @available(iOS 14.0, *)
    open class func holeDistortion() -> CIFilter & CIHoleDistortion

    @available(iOS 14.0, *)
    open class func lightTunnel() -> CIFilter & CILightTunnel

    @available(iOS 14.0, *)
    open class func ninePartStretched() -> CIFilter & CINinePartStretched

    @available(iOS 14.0, *)
    open class func ninePartTiled() -> CIFilter & CINinePartTiled

    @available(iOS 14.0, *)
    open class func pinchDistortion() -> CIFilter & CIPinchDistortion

    @available(iOS 14.0, *)
    open class func stretchCrop() -> CIFilter & CIStretchCrop

    @available(iOS 14.0, *)
    open class func torusLensDistortion() -> CIFilter & CITorusLensDistortion

    @available(iOS 14.0, *)
    open class func twirlDistortion() -> CIFilter & CITwirlDistortion

    @available(iOS 14.0, *)
    open class func vortexDistortion() -> CIFilter & CIVortexDistortion

    
    // CICategoryTileEffect
    open class func affineClamp() -> CIFilter & CIAffineClamp

    open class func affineTile() -> CIFilter & CIAffineTile

    open class func eightfoldReflectedTile() -> CIFilter & CIEightfoldReflectedTile

    open class func fourfoldReflectedTile() -> CIFilter & CIFourfoldReflectedTile

    open class func fourfoldRotatedTile() -> CIFilter & CIFourfoldRotatedTile

    open class func fourfoldTranslatedTile() -> CIFilter & CIFourfoldTranslatedTile

    open class func glideReflectedTile() -> CIFilter & CIGlideReflectedTile

    open class func kaleidoscope() -> CIFilter & CIKaleidoscope

    open class func opTile() -> CIFilter & CIOpTile

    open class func parallelogramTile() -> CIFilter & CIParallelogramTile

    open class func perspectiveTile() -> CIFilter & CIPerspectiveTile

    open class func sixfoldReflectedTile() -> CIFilter & CISixfoldReflectedTile

    open class func sixfoldRotatedTile() -> CIFilter & CISixfoldRotatedTile

    open class func triangleKaleidoscope() -> CIFilter & CITriangleKaleidoscope

    open class func triangleTile() -> CIFilter & CITriangleTile

    open class func twelvefoldReflectedTile() -> CIFilter & CITwelvefoldReflectedTile

    
    // CICategoryGenerator
    open class func attributedTextImageGenerator() -> CIFilter & CIAttributedTextImageGenerator

    open class func aztecCodeGenerator() -> CIFilter & CIAztecCodeGenerator

    open class func barcodeGenerator() -> CIFilter & CIBarcodeGenerator

    open class func checkerboardGenerator() -> CIFilter & CICheckerboardGenerator

    open class func code128BarcodeGenerator() -> CIFilter & CICode128BarcodeGenerator

    open class func lenticularHaloGenerator() -> CIFilter & CILenticularHaloGenerator

    open class func meshGenerator() -> CIFilter & CIMeshGenerator

    open class func pdf417BarcodeGenerator() -> CIFilter & CIPDF417BarcodeGenerator

    open class func qrCodeGenerator() -> CIFilter & CIQRCodeGenerator

    open class func randomGenerator() -> CIFilter & CIRandomGenerator

    open class func roundedRectangleGenerator() -> CIFilter & CIRoundedRectangleGenerator

    open class func starShineGenerator() -> CIFilter & CIStarShineGenerator

    open class func stripesGenerator() -> CIFilter & CIStripesGenerator

    open class func sunbeamsGenerator() -> CIFilter & CISunbeamsGenerator

    open class func textImageGenerator() -> CIFilter & CITextImageGenerator

    
    // CICategoryStylize
    open class func blendWithAlphaMask() -> CIFilter & CIBlendWithMask

    open class func blendWithBlueMask() -> CIFilter & CIBlendWithMask

    open class func blendWithMask() -> CIFilter & CIBlendWithMask

    open class func blendWithRedMask() -> CIFilter & CIBlendWithMask

    open class func bloom() -> CIFilter & CIBloom

    open class func comicEffect() -> CIFilter & CIComicEffect

    open class func convolution3X3() -> CIFilter & CIConvolution

    open class func convolution5X5() -> CIFilter & CIConvolution

    open class func convolution7X7() -> CIFilter & CIConvolution

    open class func convolution9Horizontal() -> CIFilter & CIConvolution

    open class func convolution9Vertical() -> CIFilter & CIConvolution

    @available(iOS 15.0, *)
    open class func convolutionRGB3X3() -> CIFilter & CIConvolution

    @available(iOS 15.0, *)
    open class func convolutionRGB5X5() -> CIFilter & CIConvolution

    @available(iOS 15.0, *)
    open class func convolutionRGB7X7() -> CIFilter & CIConvolution

    @available(iOS 15.0, *)
    open class func convolutionRGB9Horizontal() -> CIFilter & CIConvolution

    @available(iOS 15.0, *)
    open class func convolutionRGB9Vertical() -> CIFilter & CIConvolution

    open class func coreMLModel() -> CIFilter & CICoreMLModel

    open class func crystallize() -> CIFilter & CICrystallize

    open class func depthOfField() -> CIFilter & CIDepthOfField

    open class func edges() -> CIFilter & CIEdges

    open class func edgeWork() -> CIFilter & CIEdgeWork

    open class func gaborGradients() -> CIFilter & CIGaborGradients

    open class func gloom() -> CIFilter & CIGloom

    open class func heightFieldFromMask() -> CIFilter & CIHeightFieldFromMask

    open class func hexagonalPixellate() -> CIFilter & CIHexagonalPixellate

    open class func highlightShadowAdjust() -> CIFilter & CIHighlightShadowAdjust

    open class func lineOverlay() -> CIFilter & CILineOverlay

    open class func mix() -> CIFilter & CIMix

    @available(iOS 15.0, *)
    open class func personSegmentation() -> CIFilter & CIPersonSegmentation

    open class func pixellate() -> CIFilter & CIPixellate

    open class func pointillize() -> CIFilter & CIPointillize

    open class func saliencyMap() -> CIFilter & CISaliencyMap

    open class func shadedMaterial() -> CIFilter & CIShadedMaterial

    open class func spotColor() -> CIFilter & CISpotColor

    open class func spotLight() -> CIFilter & CISpotLight

    
    // CICategoryBlur
    open class func bokehBlur() -> CIFilter & CIBokehBlur

    open class func boxBlur() -> CIFilter & CIBoxBlur

    open class func discBlur() -> CIFilter & CIDiscBlur

    open class func gaussianBlur() -> CIFilter & CIGaussianBlur

    open class func maskedVariableBlur() -> CIFilter & CIMaskedVariableBlur

    open class func median() -> CIFilter & CIMedian

    open class func morphologyGradient() -> CIFilter & CIMorphologyGradient

    open class func morphologyMaximum() -> CIFilter & CIMorphologyMaximum

    open class func morphologyMinimum() -> CIFilter & CIMorphologyMinimum

    open class func morphologyRectangleMaximum() -> CIFilter & CIMorphologyRectangleMaximum

    open class func morphologyRectangleMinimum() -> CIFilter & CIMorphologyRectangleMinimum

    open class func motionBlur() -> CIFilter & CIMotionBlur

    open class func noiseReduction() -> CIFilter & CINoiseReduction

    open class func zoomBlur() -> CIFilter & CIZoomBlur

    
    // CICategoryReduction
    @available(iOS 14.0, *)
    open class func areaAverage() -> CIFilter & CIAreaAverage

    @available(iOS 14.0, *)
    open class func areaHistogram() -> CIFilter & CIAreaHistogram

    @available(iOS 16.0, *)
    open class func areaLogarithmicHistogram() -> CIFilter & CIAreaLogarithmicHistogram

    @available(iOS 14.0, *)
    open class func areaMaximum() -> CIFilter & CIAreaMaximum

    @available(iOS 14.0, *)
    open class func areaMaximumAlpha() -> CIFilter & CIAreaMaximumAlpha

    @available(iOS 14.0, *)
    open class func areaMinimum() -> CIFilter & CIAreaMinimum

    @available(iOS 14.0, *)
    open class func areaMinimumAlpha() -> CIFilter & CIAreaMinimumAlpha

    @available(iOS 14.0, *)
    open class func areaMinMax() -> CIFilter & CIAreaMinMax

    @available(iOS 14.0, *)
    open class func areaMinMaxRed() -> CIFilter & CIAreaMinMaxRed

    @available(iOS 14.0, *)
    open class func columnAverage() -> CIFilter & CIColumnAverage

    @available(iOS 14.0, *)
    open class func histogramDisplay() -> CIFilter & CIHistogramDisplay

    @available(iOS 14.0, *)
    open class func kMeans() -> CIFilter & CIKMeans

    @available(iOS 14.0, *)
    open class func rowAverage() -> CIFilter & CIRowAverage
}