那用Metal如何把YUV图像显示到指定的窗口上-Go服务器开发

在Metal中，可以使用纹理（texture）来显示YUV图像。下面是一个简单的示例代码，演示如何将YUV图像显示到指定窗口上：

创建Metal设备和命令队列：

import Metal

let device = MTLCreateSystemDefaultDevice()
let commandQueue = device?.makeCommandQueue()

创建渲染目标窗口：

import MetalKit

let view = MTKView(frame: frameRect, device: device)
view.framebufferOnly = false

加载YUV图像数据到Metal纹理中：

import CoreVideo.Metal

let textureLoader = MTKTextureLoader(device: device!)
let yuvFileURL = Bundle.main.url(forResource: "yuv_image", withExtension: "yuv")
let yuvData = try! Data(contentsOf: yuvFileURL!)

// 假设YUV图像格式为NV12或NV21
let width = 640 // 图像宽度
let height = 480 // 图像高度

// 创建Metal纹理描述符
let textureDescriptor = MTLTextureDescriptor.texture2DDescriptor(pixelFormat: .r8Unorm, width: width, height: height, mipmapped: false)

// 使用Core Video将YUV数据加载到Metal纹理中
guard let yuvTexture = CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, metalTextureCache!, pixelBuffer, nil, .r8Unorm, width, height, planeIndex, &yuvTextureOut) else {
    fatalError("Failed to create YUV texture")
}

// 将Core Video的Metal纹理转换为Metal纹理对象
let metalTexture = CVMetalTextureGetTexture(yuvTexture)

创建渲染管道：

import MetalKit

guard let library = device?.makeDefaultLibrary() else {
    fatalError("Failed to create Metal library")
}

let pipelineDescriptor = MTLRenderPipelineDescriptor()
pipelineDescriptor.vertexFunction = library.makeFunction(name: "vertexShader")
pipelineDescriptor.fragmentFunction = library.makeFunction(name: "fragmentShader")
pipelineDescriptor.colorAttachments[0].pixelFormat = view.colorPixelFormat

let pipelineState = try! device?.makeRenderPipelineState(descriptor: pipelineDescriptor)

实现渲染函数：

func render(in view: MTKView) {
    guard let drawable = view.currentDrawable, let descriptor = view.currentRenderPassDescriptor else {
        return
    }
    
    // 创建命令缓冲区和编码器
    guard let commandBuffer = commandQueue?.makeCommandBuffer(),
          let encoder = commandBuffer.makeRenderCommandEncoder(descriptor: descriptor) else {
        return
    }
    
    // 设置渲染管道状态和纹理
    encoder.setRenderPipelineState(pipelineState!)
    encoder.setTexture(metalTexture, index: 0)
    
    // 绘制一个全屏矩形（四个顶点）
    encoder.drawPrimitives(type: .triangleStrip, vertexStart: 0, vertexCount: 4)
    
    // 结束并提交绘制命令
    encoder.endEncoding()
    commandBuffer.present(drawable)
    commandBuffer.commit()
}

在合适的地方调用渲染函数来显示YUV图像到窗口上：

view.delegate = self

// 在需要显示图像时调用渲染函数
func view(_ view: MTKView, drawableSizeWillChange size: CGSize) {
    // ...
}

func draw(in view: MTKView) {
    render(in: view)
}

请注意，上述代码仅为示例，实际使用时还需要根据具体需求进行适当的修改和完善。

内容由零声教学AI助手提供，问题来源于学员提问