如何以编程方式将任何 MTLTexture 导出到 Swift 中的 KTX

Question

细节

我们可以通过帧捕获在捕获帧之后以KTX格式导出包括其他层或切片的原始纹理数据。

之后，我们可以使用MTKTextureLoader导入。

let texture = try! await loader.newTexture(URL: Bundle.main.url(forResource: "texture", withExtension: "ktx")!)

目标

但是如何以编程方式将 MTLTexture 导出为 Swift 中的 KTX 格式？

Answer 1

您可以检查ImageIO是否支持您要导出到的格式：

从ImageIO模块调用CGImageDestinationCopyTypeIdentifiers()以获取CGImageDestination支持的所有 UTI 的列表。

然后，使用CGImage到 output 吧：

let texture: MTLTexture = ... // input texture
let ciContext = CIContext(mtlDevice: texture.device)
let ciImage = CIImage(mtlTexture: texture, options: nil) // you might need to add `.oriented(.downMirrored)` here
let colorspace = CGColorSpace(name: CGColorSpace.sRGB)
let cgImage = ciContext.createCGImage(ciImage, from: .init(origin: .zero, size: .init(width: texture.width, height: texture.height)), format: .RGBA8, colorSpace: colorspace)!

let uniformType: UTType = ... // uniform type from CGImageDestinationCopyTypeIdentifiers
let outputURL: URL = ... // the url

try FileManager.default.createDirectory(at: outputURL.deletingLastPathComponent(), withIntermediateDirectories: true) // you might needs this to create intermediate directories

let destination = CGImageDestinationCreateWithURL(outputURL as CFURL, uniformType.identifier as CFString, 1, nil)!
CGImageDestinationAddImage(destination, cgImage, nil)
let imageOutputSuccessfully = CGImageDestinationFinalize(destination)