ios - 从 MtlTexture 获取字节以创建 CVPixelBufferRef
问题描述
尝试在 SCNRender 对象的每个调用渲染上从 MTLTexture 创建 CVPixelBufferRef:
CVPixelBufferLockBaseAddress(pixelBuffer!, CVPixelBufferLockFlags(rawValue: 0))
let bytesPerRow = 4 * Int(textureSizeX)
let region = MTLRegionMake2D(0, 0, Int(textureSizeX), Int(textureSizeY))
var tmpBuffer = CVPixelBufferGetBaseAddress(pixelBuffer!);
offscreenTexture.getBytes(tmpBuffer!, bytesPerRow: bytesPerRow, from: region, mipmapLevel: 0)
CVPixelBufferUnlockBaseAddress(pixelBuffer!, CVPixelBufferLockFlags(rawValue: 0))
然后转换为 UIImage 显示在屏幕上
let ciImage = CIImage.init(cvPixelBuffer: pixelBuffer!)
let temporaryContext = CIContext(options: nil)
let tempImage = temporaryContext.createCGImage(ciImage, from: CGRect(x: 0, y: 0, width: textureSizeX, height: textureSizeY))
let uiImage = UIImage.init(cgImage: tempImage!)
但图像不显示
解决方案
我遇到了同样的问题并找到了以下解决方案。它就像一个魅力:)
func image(from texture: MTLTexture) -> UIImage? {
let bytesPerPixel = 4
// The total number of bytes of the texture
let imageByteCount = texture.width * texture.height * bytesPerPixel
// The number of bytes for each image row
let bytesPerRow = texture.width * bytesPerPixel
// An empty buffer that will contain the image
var src = [UInt8](repeating: 0, count: Int(imageByteCount))
// Gets the bytes from the texture
let region = MTLRegionMake2D(0, 0, texture.width, texture.height)
texture.getBytes(&src, bytesPerRow: bytesPerRow, from: region, mipmapLevel: 0)
// Creates an image context
let bitmapInfo = CGBitmapInfo(rawValue: (CGBitmapInfo.byteOrder32Big.rawValue | CGImageAlphaInfo.premultipliedLast.rawValue))
let bitsPerComponent = 8
let colorSpace = CGColorSpaceCreateDeviceRGB()
let context = CGContext(data: &src, width: texture.width, height: texture.height, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo.rawValue)
// Creates the image from the graphics context
guard let dstImage = context?.makeImage() else { return nil }
// Creates the final UIImage
return UIImage(cgImage: dstImage, scale: 0.0, orientation: .up)
}
来源:https ://www.invasivecode.com/weblog/metal-image-processing 您可能还感兴趣:https ://github.com/hollance/CoreMLHelpers/tree/master/CoreMLHelpers
推荐阅读
- python - 出现 Django 2.1.5 服务器错误。请联系管理员“错误:UnicodeDecodeError
- c++ - node.prev.next = ... 和 node = 之间的区别
- authentication - 将当前用户数据从本地存储存储到 vue 存储的最佳实践?
- javascript - Vue中缺少必需的道具
- python - Python中不同维度数组的向量化计算
- macos - 使用 CGDisplayStreamCreate 和 Metal
- c++ - 英特尔 SGX 将 c++ 类/结构作为 void* 传递给 enclave 并将其转换回
- matlab - 将级数求和的计算调整为在求和的每一步除以 n
- .net - 创建 WMI 实例(例如使用 InstrumentationManager.Publish)需要哪些权限?
- arrays - 迭代字典数组以获得最高 gpa