int main()
{
// Create Device
const D3D_FEATURE_LEVEL lvl[] = { D3D_FEATURE_LEVEL_11_1 };
UINT createDeviceFlags = 0;
#ifdef _DEBUG
createDeviceFlags |= D3D11_CREATE_DEVICE_DEBUG;
#endif
/* ================================== */
printf("Creating device...");
ID3D11Device* device = nullptr;
HRESULT hr = D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, createDeviceFlags, lvl, _countof(lvl), D3D11_SDK_VERSION, &device, nullptr, nullptr);
if (FAILED(hr))
{
printf("Failed creating Direct3D 11 device %08X\n", hr);
return returnDBG(-1);
}
/* ================================== */
printf("Compile Compute Shader...");
ID3DBlob *csBlob = nullptr;
hr = CompileComputeShader(L"ComputeShader.hlsl", "main", device, &csBlob);
if (FAILED(hr))
{
device->Release();
printf("Failed compiling shader %08X\n", hr);
return returnDBG(-1);
}
/* ================================== */
printf("Create Compute Shader...");
ID3D11ComputeShader* computeShader = nullptr;
hr = device->CreateComputeShader(csBlob->GetBufferPointer(), csBlob->GetBufferSize(), nullptr, &computeShader);
/* ================================== */
printf("Creating buffers and filling them with initial data...");
for (int i = 0; i < NUM_ELEMENTS; ++i)
{
g_vBuf0[i].i = i;
g_vBuf0[i].f = (float)i;
g_vBuf1[i].i = i;
g_vBuf1[i].f = (float)i;
}
CreateRawBuffer(g_pDevice, NUM_ELEMENTS * sizeof(BufType), &g_vBuf0[0], &g_pBuf0);
CreateRawBuffer(g_pDevice, NUM_ELEMENTS * sizeof(BufType), &g_vBuf1[0], &g_pBuf1);
CreateRawBuffer(g_pDevice, NUM_ELEMENTS * sizeof(BufType), nullptr, &g_pBufResult);
/* ================================== */
printf("Running Compute Shader...");
ID3D11ShaderResourceView* aRViews[2] = { g_pBuf0SRV, g_pBuf1SRV };
RunComputeShader(g_pContext, g_pCS, 2, aRViews, nullptr, nullptr, 0, g_pBufResultUAV, NUM_ELEMENTS, 1, 1);
printf("done\n");
csBlob->Release();
if (FAILED(hr))
{
device->Release();
}
printf("Success\n");
// Clean up
computeShader->Release();
device->Release();
return returnDBG(0);
}
int _tmain(int /*argc*/, _TCHAR* /*argv[]*/)
{
// GROUP_SIZE_X defined in kernel.hlsl must match the
// groupSize declared here.
size_t const groupSize = 512;
size_t const numGroups = 16;
size_t const dimension = numGroups*groupSize;
// Create a D3D11 device and immediate context.
// TODO: The code below uses the default video adapter, with the
// default set of feature levels. Please see the MSDN docs if
// you wish to control which adapter and feature level are used.
D3D_FEATURE_LEVEL featureLevel;
ID3D11Device* device = nullptr;
ID3D11DeviceContext* context = nullptr;
HRESULT hr = D3D11CreateDevice(NULL, D3D_DRIVER_TYPE_HARDWARE, NULL,
NULL, NULL, 0, D3D11_SDK_VERSION, &device,
&featureLevel, &context);
if (FAILED(hr))
{
printf("D3D11CreateDevice failed with return code %x\n", hr);
return hr;
}
// Create system memory and fill it with our initial data. Note that
// these data structures aren't really necessary , it's just a demonstration
// of how you can take existing data structures you might have and copy
// their data to/from GPU computations.
std::vector<float> x(dimension);
std::vector<float> y(dimension);
std::vector<float> z(dimension);
float const a = 2.0f;
for (size_t i = 0; i < dimension; ++ i)
{
x[i] = static_cast<float>(i);
y[i] = 100 - static_cast<float>(i);
}
// Create structured buffers for the "x" and "y" vectors.
D3D11_BUFFER_DESC inputBufferDesc;
inputBufferDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
// The buffers are read-only by the GPU, writeable by the CPU.
// TODO: If you will never again upate the data in a GPU buffer,
// you might want to look at using a D3D11_SUBRESOURCE_DATA here to
// provide the initialization data instead of doing the mapping
// and copying that happens below.
inputBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
inputBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
inputBufferDesc.MiscFlags = D3D11_RESOURCE_MISC_BUFFER_STRUCTURED;
inputBufferDesc.StructureByteStride = sizeof(float);
inputBufferDesc.ByteWidth = sizeof(float) * dimension;
ID3D11Buffer* xBuffer = nullptr;
hr = device->CreateBuffer(&inputBufferDesc, NULL, &xBuffer);
if (FAILED(hr))
{
printf("CreateBuffer failed for x buffer with return code %x\n", hr);
return hr;
}
// We can re-use inputBufferDesc here because the layout and usage of the x
// and y buffers is exactly the same.
ID3D11Buffer* yBuffer = nullptr;
hr = device->CreateBuffer(&inputBufferDesc, NULL, &yBuffer);
if (FAILED(hr))
{
printf("CreateBuffer failed for x buffer with return code %x\n", hr);
return hr;
}
// Create shader resource views for the "x" and "y" buffers.
// TODO: You can optionally provide a D3D11_SHADER_RESOURCE_VIEW_DESC
// as the second parameter if you need to use only part of the buffer
// inside the compute shader.
ID3D11ShaderResourceView* xSRV = nullptr;
hr = device->CreateShaderResourceView(xBuffer, NULL, &xSRV);
if (FAILED(hr))
{
printf("CreateShaderResourceView failed for x buffer with return code %x\n", hr);
return hr;
}
ID3D11ShaderResourceView* ySRV = nullptr;
hr = device->CreateShaderResourceView(yBuffer, NULL, &ySRV);
if (FAILED(hr))
{
printf("CreateShaderResourceView failed for y buffer with return code %x\n", hr);
return hr;
}
// Create a structured buffer for the "z" vector. This buffer needs to be
// writeable by the GPU, so we can't create it with CPU read/write access.
D3D11_BUFFER_DESC outputBufferDesc;
outputBufferDesc.BindFlags = D3D11_BIND_UNORDERED_ACCESS
| D3D11_BIND_SHADER_RESOURCE;
outputBufferDesc.Usage = D3D11_USAGE_DEFAULT;
outputBufferDesc.CPUAccessFlags = 0;
outputBufferDesc.MiscFlags = D3D11_RESOURCE_MISC_BUFFER_STRUCTURED;
outputBufferDesc.StructureByteStride = sizeof(float);
outputBufferDesc.ByteWidth = sizeof(float) * dimension;
ID3D11Buffer* zBuffer = nullptr;
hr = device->CreateBuffer(&outputBufferDesc, NULL, &zBuffer);
if (FAILED(hr))
{
printf("CreateBuffer failed for z buffer with return code %x\n", hr);
return hr;
}
// Create an unordered access view for the "z" vector.
D3D11_UNORDERED_ACCESS_VIEW_DESC outputUAVDesc;
outputUAVDesc.Buffer.FirstElement = 0;
outputUAVDesc.Buffer.Flags = 0;
outputUAVDesc.Buffer.NumElements = dimension;
outputUAVDesc.Format = DXGI_FORMAT_UNKNOWN;
outputUAVDesc.ViewDimension = D3D11_UAV_DIMENSION_BUFFER;
ID3D11UnorderedAccessView* zBufferUAV;
hr = device->CreateUnorderedAccessView(zBuffer,
&outputUAVDesc, &zBufferUAV);
if (FAILED(hr))
{
printf("CreateUnorderedAccessView failed for z buffer with return code %x\n", hr);
return hr;
}
// Create a staging buffer, which will be used to copy back from zBuffer.
D3D11_BUFFER_DESC stagingBufferDesc;
stagingBufferDesc.BindFlags = 0;
stagingBufferDesc.Usage = D3D11_USAGE_STAGING;
stagingBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
stagingBufferDesc.MiscFlags = D3D11_RESOURCE_MISC_BUFFER_STRUCTURED;
stagingBufferDesc.StructureByteStride = sizeof(float);
stagingBufferDesc.ByteWidth = sizeof(float) * dimension;
ID3D11Buffer* stagingBuffer;
hr = device->CreateBuffer(&stagingBufferDesc, NULL, &stagingBuffer);
if (FAILED(hr))
{
printf("CreateBuffer failed for staging buffer with return code %x\n", hr);
return hr;
}
// Create a constant buffer (this buffer is used to pass the constant
// value 'a' to the kernel as cbuffer Constants).
D3D11_BUFFER_DESC cbDesc;
cbDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
cbDesc.Usage = D3D11_USAGE_DYNAMIC;
cbDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
cbDesc.MiscFlags = 0;
// Even though the constant buffer only has one float, DX expects
// ByteWidth to be a multiple of 4 floats (i.e., one 128-bit register).
cbDesc.ByteWidth = sizeof(float)*4;
ID3D11Buffer* constantBuffer = nullptr;
hr = device->CreateBuffer( &cbDesc, NULL, &constantBuffer);
if (FAILED(hr))
{
printf("CreateBuffer failed for constant buffer with return code %x\n", hr);
return hr;
}
// Map the constant buffer and set the constant value 'a'.
D3D11_MAPPED_SUBRESOURCE mappedResource;
context->Map(constantBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
float* constants = reinterpret_cast<float*>(mappedResource.pData);
constants[0] = a;
constants = nullptr;
context->Unmap(constantBuffer, 0);
// Map the x buffer and copy our data into it.
context->Map(xBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
float* xvalues = reinterpret_cast<float*>(mappedResource.pData);
memcpy(xvalues, &x[0], sizeof(float)*x.size());
xvalues = nullptr;
context->Unmap(xBuffer, 0);
// Map the y buffer and copy our data into it.
context->Map(yBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
float* yvalues = reinterpret_cast<float*>(mappedResource.pData);
memcpy(yvalues, &y[0], sizeof(float)*y.size());
yvalues = nullptr;
context->Unmap(yBuffer, 0);
// Compile the compute shader into a blob.
ID3DBlob* errorBlob = nullptr;
ID3DBlob* shaderBlob = nullptr;
hr = D3DX11CompileFromFile(L"kernel.hlsl", NULL, NULL, "saxpy", "cs_4_0",
D3D10_SHADER_ENABLE_STRICTNESS, 0, NULL, &shaderBlob, &errorBlob, NULL);
if (FAILED(hr))
{
// Print out the error message if there is one.
if (errorBlob)
{
char const* message = (char*)errorBlob->GetBufferPointer();
printf("kernel.hlsl failed to compile; error message:\n");
printf("%s\n", message);
errorBlob->Release();
}
return hr;
}
// Create a shader object from the compiled blob.
ID3D11ComputeShader* computeShader;
hr = device->CreateComputeShader(shaderBlob->GetBufferPointer(),
shaderBlob->GetBufferSize(), NULL, &computeShader);
if (FAILED(hr))
{
printf("CreateComputeShader failed with return code %x\n", hr);
return hr;
}
// Make the shader active.
context->CSSetShader(computeShader, NULL, 0);
// Attach the z buffer to the output via its unordered access view.
UINT initCounts = 0xFFFFFFFF;
context->CSSetUnorderedAccessViews(0, 1, &zBufferUAV, &initCounts);
// Attach the input buffers via their shader resource views.
context->CSSetShaderResources(0, 1, &xSRV);
context->CSSetShaderResources(1, 1, &ySRV);
// Attach the constant buffer
context->CSSetConstantBuffers(0, 1, &constantBuffer);
// Execute the shader, in 'numGroups' groups of 'groupSize' threads each.
context->Dispatch(numGroups, 1, 1);
// Copy the z buffer to the staging buffer so that we can
// retrieve the data for accesss by the CPU.
context->CopyResource(stagingBuffer, zBuffer);
// Map the staging buffer for reading.
context->Map(stagingBuffer, 0, D3D11_MAP_READ, 0, &mappedResource);
float* zData = reinterpret_cast<float*>(mappedResource.pData);
memcpy(&z[0], zData, sizeof(float)*z.size());
zData = nullptr;
context->Unmap(stagingBuffer, 0);
// Now compare the GPU results against expected values.
bool resultOK = true;
for (size_t i = 0; i < x.size(); ++ i)
{
// NOTE: This comparison assumes the GPU produces *exactly* the
// same result as the CPU. In general, this will not be the case
// with floating-point calculations.
float const expected = a*x[i] + y[i];
if (z[i] != expected)
{
printf("Unexpected result at position %lu: expected %.7e, got %.7e\n",
i, expected, z[i]);
resultOK = false;
}
}
if (!resultOK)
{
printf("GPU results differed from the CPU results.\n");
OutputDebugStringA("GPU results differed from the CPU results.\n");
return 1;
}
printf("GPU output matched the CPU results.\n");
OutputDebugStringA("GPU output matched the CPU results.\n");
// Disconnect everything from the pipeline.
ID3D11UnorderedAccessView* nullUAV = nullptr;
context->CSSetUnorderedAccessViews( 0, 1, &nullUAV, &initCounts);
ID3D11ShaderResourceView* nullSRV = nullptr;
context->CSSetShaderResources(0, 1, &nullSRV);
context->CSSetShaderResources(1, 1, &nullSRV);
ID3D11Buffer* nullBuffer = nullptr;
context->CSSetConstantBuffers(0, 1, &nullBuffer);
// Release resources. Again, note that none of the error checks above
// release resources that have been allocated up to this point, so the
// sample doesn't clean up after itself correctly unless everything succeeds.
computeShader->Release();
shaderBlob->Release();
constantBuffer->Release();
stagingBuffer->Release();
zBufferUAV->Release();
zBuffer->Release();
xSRV->Release();
xBuffer->Release();
ySRV->Release();
yBuffer->Release();
context->Release();
device->Release();
return 0;
}