Question

帮我弄清楚金属api，我想通过mtlView渲染普通图片，但这对我不起作用，这是我的代码，我在做什么错？接下来，我想使用UISlider和CIColorControls以60fps更改此图片的对比度，请说明。

import MetalKit

class ViewController: UIViewController, MTKViewDelegate {

    let device = MTLCreateSystemDefaultDevice()
    let colorSpace = CGColorSpaceCreateDeviceRGB()

    lazy var commandQueue: MTLCommandQueue = {
        [unowned self] in

        return self.device!.makeCommandQueue()
        }()!

    lazy var ciContext: CIContext = {
        [unowned self] in

        return CIContext(mtlDevice: self.device!)
        }()

    @IBOutlet weak var mtlView: MTKView!
    let filter = CIFilter(name: "CIPhotoEffectProcess" )
    let contrastFilter = CIFilter(name: "CIColorControls")
    var image = CIImage()

    @IBOutlet weak var slider: UISlider!


    override func viewDidLoad() {
        super.viewDidLoad()
        mtlView.delegate = self

        let img = UIImage(named: "picture")
        let ciImage = CIImage(image: img!)
        image = ciImage!
    }


    func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {

    }

    func draw(in view: MTKView) {
        guard let targetTexture = view.currentDrawable?.texture else {
            return
        }

        let commandBuffer = commandQueue.makeCommandBuffer()

        let bounds = CGRect(origin: CGPoint.zero, size: view.drawableSize)

        ciContext.render(image,
                         to: targetTexture,
                         commandBuffer: commandBuffer,
                         bounds: bounds,
                         colorSpace: colorSpace)

        commandBuffer?.present(view.currentDrawable!)
        commandBuffer?.commit()
    }
}

Answer 1

我看不到任何将device设置为MTKView的代码。没有MTKView的{{1}}将返回空的device。我建议将其添加到drawable：

viewDidLoad

使用Metal Api在mtlView中渲染图像

1 个答案: