Question

我有一组Metal纹理，它们作为纹理集存储在Xcode Assets目录中。我使用MTKTextureLoader.newTexture(name:scaleFactor:bundle:options)加载这些内容。

然后我使用MTLArgumentEncoder将所有纹理编码为Metal 2参数缓冲区。

这很有效。然而，介绍金属2 WWDC 2017会议non-overlapping occurrences，我非常渴望尝试这一点。根据{{3}}，您不必在参数缓冲区中的每个纹理上调用MTLRenderCommandEncoder.useResource，而只需在堆上调用纹理分配的useHeap。

但是，我还没有找到一种直接使用MTKTextureLoader和MTLHeap的方式。它似乎没有一个加载选项来从堆中分配纹理。

我猜测方法是：

使用MTKTextureLoader
为每个纹理反向设计一组MTLTextureDescriptor个对象
使用纹理描述符创建适当大小的MTLHeap
从MTLHeap
使用某种方法复制纹理，可能是replaceBytes，甚至是MTLBlitCommandEncoder
取消分配使用MTKTextureLoader

这似乎是一个相当冗长的方法，而且我没有看到任何这方面的例子，所以我想我先问这里，以防我错过了一些明显的东西。

我应该放弃MTKTextureLoader，并在从资产目录中加载纹理时搜索一些前MetalKit艺术品吗？

我使用Swift，但很高兴接受Objective-C答案。

Answer 1

嗯，我上面概述的方法似乎有效。正如预测的那样，它非常啰嗦。我很想知道是否有人有更优雅的东西。

enum MetalError: Error {
    case anErrorOccured
}

extension MTLTexture {
    var descriptor: MTLTextureDescriptor {
        let descriptor = MTLTextureDescriptor()
        descriptor.width = width
        descriptor.height = height
        descriptor.depth = depth
        descriptor.textureType = textureType
        descriptor.cpuCacheMode = cpuCacheMode
        descriptor.storageMode = storageMode
        descriptor.pixelFormat = pixelFormat
        descriptor.arrayLength = arrayLength
        descriptor.mipmapLevelCount = mipmapLevelCount
        descriptor.sampleCount = sampleCount
        descriptor.usage = usage
        return descriptor
    }

    var size: MTLSize {
        return MTLSize(width: width, height: height, depth: depth)
    }
}

extension MTKTextureLoader {
    func newHeap(withTexturesNamed names: [String], queue: MTLCommandQueue, scaleFactor: CGFloat, bundle: Bundle?, options: [MTKTextureLoader.Option : Any]?, onCompletion: (([MTLTexture]) -> Void)?) throws -> MTLHeap {
        let device = queue.device
        let sourceTextures = try names.map { name in
            return try newTexture(name: name, scaleFactor: scaleFactor, bundle: bundle, options: options)
        }
        let storageMode: MTLStorageMode = .private
        let descriptors: [MTLTextureDescriptor] = sourceTextures.map { source in
            let desc = source.descriptor
            desc.storageMode = storageMode
            return desc
        }
        let sizeAligns = descriptors.map { device.heapTextureSizeAndAlign(descriptor: $0) }
        let heapDescriptor = MTLHeapDescriptor()
        heapDescriptor.size = sizeAligns.reduce(0) { $0 + $1.size }
        heapDescriptor.cpuCacheMode = descriptors[0].cpuCacheMode
        heapDescriptor.storageMode = storageMode
        guard let heap = device.makeHeap(descriptor: heapDescriptor),
            let buffer = queue.makeCommandBuffer(),
            let blit = buffer.makeBlitCommandEncoder()
            else {
            throw MetalError.anErrorOccured
        }
        let destTextures = descriptors.map { descriptor in
            return heap.makeTexture(descriptor: descriptor)
        }
        let origin = MTLOrigin()
        zip(sourceTextures, destTextures).forEach {(source, dest) in
            blit.copy(from: source, sourceSlice: 0, sourceLevel: 0, sourceOrigin: origin, sourceSize: source.size, to: dest, destinationSlice: 0, destinationLevel: 0, destinationOrigin: origin)
            blit.generateMipmaps(for: dest)
        }
        blit.endEncoding()
        buffer.addCompletedHandler { _ in
            onCompletion?(destTextures)
        }
        buffer.commit()
        return heap
    }
}

如何将MetalKit纹理加载器与Metal堆一起使用？

1 个答案: