更新Metal中MTLBuffer的内容 [英] Update contents of MTLBuffer in Metal

问题描述

我需要帮助来替换 MTLBuffer 的内容，而无需创建新内容.两种情况下的内容都是浮点数组.

I need help to replace the contents of a MTLBuffer without creating a new one. Content in both cases are Float Arrays.

let vector:[Float] = [0,1,2,3,4,5,6,7,8,9]   
let byteLength = arr1.count*MemoryLayout<Float>.size
let buffer = metalDevice.makeBuffer(bytes: &vector, length: byteLength, options: MTLResourceOptions())

let vector2:[Float] = [10,20,30,40,50,60,70,80,90]

我了解 buffer.contents()给了我们 UnsafeMutableRawPointer .我想从 vector2 创建一个新的UnsafeMutableRawPointer并替换缓冲区的内容.

I understand buffer.contents() gives us a UnsafeMutableRawPointer. I would like to create a new UnsafeMutableRawPointer from vector2 and replace the contents of buffer.

提前谢谢！

推荐答案

您可以使用memcpy进行此操作，但是稍微快一点的方法是:

You can do this with memcpy, but the slightly Swiftier way is:

buffer.contents().copyBytes(from: vector2, count: vector2.count * MemoryLayout<Float>.stride)

通常，在计算以字节为单位的数组长度时，优先使用stride而不是size.如果该类型不是原始类型并且具有任何填充，则size不会解决此问题，并且您复制的字节将少于您的预期.

In general, prefer stride over size when calculating the length of an array in bytes. If the type is not primitive and has any padding, size will not account for this, and you'll copy fewer bytes than you intended.

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