When I initialize my ID3D11UnorderedAccessView's buffer to be any larger than 16 bytes, my shader's output is blank. What could be causing this?

Question

I have the following function to create my UAV and initialize a buffer for it:

        template <typename T>
        static inline void CreateInitializedUnorderedAccessView(
            _In_ ID3D11Device* pDevice,
            UINT count,
            _In_ D3D11_SUBRESOURCE_DATA* pData,
            _Out_ ID3D11Buffer** ppBuffer,
            _Out_ ID3D11UnorderedAccessView** ppUav)
        {
            D3D11_BUFFER_DESC bufferDesc =
            {
                sizeof(T) * count, // ByteWidth
                D3D11_USAGE_DEFAULT, // Usage
                D3D11_BIND_UNORDERED_ACCESS, // BindFlags
                0, // CPUAccessFlags
                D3D11_RESOURCE_MISC_BUFFER_STRUCTURED, // MiscFlags
                sizeof(T), // StructureByteStride
            };

            CHR(pDevice->CreateBuffer(
                &bufferDesc,
                pData,
                ppBuffer));

            D3D11_UNORDERED_ACCESS_VIEW_DESC uaView =
            {
                DXGI_FORMAT_UNKNOWN, // Format
                D3D11_UAV_DIMENSION_BUFFER, // ViewDimension
            };

            uaView.Buffer.FirstElement = 0;
            uaView.Buffer.Flags = 0;
            uaView.Buffer.NumElements = count;

            CHR(pDevice->CreateUnorderedAccessView(
                *ppBuffer,
                &uaView,
                ppUav));
        }

Ignore CHR, that's a macro for handling exceptions. T is usually a 128 bit type, e.g. __m128i or __n128.

When I call this function:

::CreateInitializedUnorderedAccessView<simd_4>(
    this->device.Get(),
    1, //this->dataStruct.SysMemPitch / sizeof(simd_4),
    &this->dataStruct,
    this->outputBuffer.GetAddressOf(),
    this->outputView.GetAddressOf());

My shader does exactly what I expect it to do, and writes to the first 128 bits of the UAV's buffer which I verify later.

However, when I call CreateInitializedUnorderedAccessView with ANY number larger than 1 for count (e.g. 2,3,4, 16, or, ideally, this->dataStruct.SysMemPitch/sizeof(simd_4)), the UAV's buffer isn't written to at all which should be impossible from how I wrote the shader--although I'm not certain of that, so I'll include some of the relevant HLSL assembly here:

cs_5_0
dcl_globalFlags refactoringAllowed
dcl_constantbuffer cb0[2], immediateIndexed
dcl_constantbuffer cb1[1], immediateIndexed
dcl_uav_structured u0, 16
dcl_input vThreadID.xy
dcl_temps 25
dcl_thread_group 64, 1, 1
imad r24.w, vThreadID.y, l(0x003fffc0), vThreadID.x
if_z r24.w
mov r0.xyzw, l(0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff)
store_structured u0.xyzw, l(0), l(0), r0.xyzw
endif

...

which should, after running the shader, set the first 128 bits in the UAV to 1... but they are all 0 when I feed a count of anything other than 1 to my CreateInitializedUnorderedAccessView function. What could be causing this?

Have you enabled the debug device and looked for diagnostic output? — Chuck Walbourn, Jun 05 '17 at 17:48
This is a little unusual to create a gpu writable buffer (uav) while providing an initialdata at create buffer no ? — galop1n, Jun 05 '17 at 18:50

When I initialize my ID3D11UnorderedAccessView's buffer to be any larger than 16 bytes, my shader's output is blank. What could be causing this?

0 Answers0