我可以使用控制台输出调试我的金属着色语言代码(比如在
Swift中打印)吗？
如果有,怎么样？
如果不是,有没有其他方法从我的.Metal文件输出变量？ (也许通过使用commandEncoder-buffer将数据从.Metal文件传递到我的.swift文件？)
我没有成功尝试通过commandEncoder传递对Int变量(在我的.swift文件中)的引用到我的.Metal文件.在.Metal文件中,我为int变量赋值,但是如果我在swift文件中打印Int,则指定的值不存在.
.swift文件：
... var myMetalOutput: Int = 0 ... let printBuffer = device.newBufferWithBytes(&myMetalOutput,length: sizeof(Int),options: MTLResourceOptions.cpuCacheModeDefaultCache) commandEncoder.setBuffer(printBuffer,offset: 0,atIndex: 8) ... commandBuffer.commit() drawable.present() print("myMetalOutput: \(myMetalOutput)") ...
...
kernel void shader(...,device int &printBuffer [[8]],...) {
...
printBuffer = 123;
...
}
解决方法
如果有人需要,这是一个有效的解决方案：
let device = MTLCreateSystemDefaultDevice()!
let commandQueue = device.newCommandQueue()
let defaultLibrary = device.newDefaultLibrary()!
let commandBuffer = commandQueue.commandBuffer()
let computeCommandEncoder = commandBuffer.computeCommandEncoder()
let program = defaultLibrary.newFunctionWithName("shader")
do
{
let computePipelineFilter = try device.newComputePipelineStateWithFunction(program!)
computeCommandEncoder.setComputePipelineState(computePipelineFilter)
var resultdata = [Int](count: 1,repeatedValue: 0)
let outVectorBuffer = device.newBufferWithBytes(&resultdata,length: sizeofValue(1),options: MTLResourceOptions.cpuCacheModeDefaultCache)
computeCommandEncoder.setBuffer(outVectorBuffer,atIndex: 0)
let threadsPerGroup = MTLSize(width:1,height:1,depth:1)
let numThreadgroups = MTLSize(width:1,depth:1)
computeCommandEncoder.dispatchThreadgroups(numThreadgroups,threadsPerThreadgroup: threadsPerGroup)
computeCommandEncoder.endEncoding()
commandBuffer.addCompletedHandler {commandBuffer in
let data = NSData(bytes: outVectorBuffer.contents(),length: sizeof(NSInteger))
var out: NSInteger = 0
data.getBytes(&out,length: sizeof(NSInteger))
print("data: \(out)")
}
commandBuffer.commit()
}
catch
{
fatalError("newComputePipelineStateWithFunction Failed ")
}
着色器：
kernel void shader(device int &printBuffer [[buffer(0)]],uint id [[ thread_position_in_grid ]]) {
printBuffer = 123;
}
