如何在不使用CAMetalDrawable的情况下获得渲染纹理？

import Metal
import MetalKit

// 获取Metal设备
guard let device = MTLCreateSystemDefaultDevice() else {
    fatalError("Metal is not supported on this device")
}

// 创建一个命令队列
let commandQueue = device.makeCommandQueue()!

// 创建一个纹理描述符
let textureDescriptor = MTLTextureDescriptor.texture2DDescriptor(
    pixelFormat: .rgba8Unorm,
    width: 512,
    height: 512,
    mipmapped: false)

// 创建纹理
guard let texture = device.makeTexture(descriptor: textureDescriptor) else {
    fatalError("Failed to create texture")
}

// 创建一个渲染通道描述符
let renderPassDescriptor = MTLRenderPassDescriptor()
renderPassDescriptor.colorAttachments[0].texture = texture
renderPassDescriptor.colorAttachments[0].loadAction = .clear
renderPassDescriptor.colorAttachments[0].storeAction = .store
renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColor(red: 0.0, green: 0.0, blue: 0.0, alpha: 1.0)

// 创建一个命令缓冲区
guard let commandBuffer = commandQueue.makeCommandBuffer() else {
    fatalError("Failed to create command buffer")
}

// 创建一个渲染管道状态（假设已经创建）
guard let renderPipelineState = createRenderPipelineState(device: device) else {
    fatalError("Failed to create render pipeline state")
}

// 创建一个渲染编码器
let renderEncoder = commandBuffer.makeRenderCommandEncoder(descriptor: renderPassDescriptor)!
renderEncoder.setRenderPipelineState(renderPipelineState)
renderEncoder.drawPrimitives(type: .triangle, vertexStart: 0, vertexCount: 3)
renderEncoder.endEncoding()

// 提交命令缓冲区
commandBuffer.commit()

// 辅助函数：创建渲染管道状态
func createRenderPipelineState(device: MTLDevice) -> MTLRenderPipelineState? {
    // 这里省略了创建渲染管道状态的详细步骤
    // 参考链接：https://developer.apple.com/documentation/metal/creating_a_render_pipeline_state_object
    return nil
}